All Enso objects are hasheable (#3878)

* Hash codes prototype

* Remove Any.hash_code

* Improve caching of hashcode in atoms

* [WIP] Add Hash_Map type

* Implement Any.hash_code builtin for primitives and vectors

* Add some values to ValuesGenerator

* Fix example docs on Time_Zone.new

* [WIP] QuickFix for HashCodeTest before PR #3956 is merged

* Fix hash code contract in HashCodeTest

* Add times and dates values to HashCodeTest

* Fix docs

* Remove hashCodeForMetaInterop specialization

* Introduce snapshoting of HashMapBuilder

* Add unit tests for EnsoHashMap

* Remove duplicate test in Map_Spec.enso

* Hash_Map.to_vector caches result

* Hash_Map_Spec is a copy of Map_Spec

* Implement some methods in Hash_Map

* Add equalsHashMaps specialization to EqualsAnyNode

* get and insert operations are able to work with polyglot values

* Implement rest of Hash_Map API

* Add test that inserts elements with keys with same hash code

* EnsoHashMap.toDisplayString use builder storage directly

* Add separate specialization for host objects in EqualsAnyNode

* Fix specialization for host objects in EqualsAnyNode

* Add polyglot hash map tests

* EconomicMap keeps reference to EqualsNode and HashCodeNode.

Rather than passing these nodes to `get` and `insert` methods.

* HashMapTest run in polyglot context

* Fix containsKey index handling in snapshots

* Remove snapshots field from EnsoHashMapBuilder

* Prepare polyglot hash map handling.

- Hash_Map builtin methods are separate nodes

* Some bug fixes

* Remove ForeignMapWrapper.

We would have to wrap foreign maps in assignments for this to be efficient.

* Improve performance of Hash_Map.get_builtin

Also, if_nothing parameter is suspended

* Remove to_flat_vector.

Interop API requires nested vector (our previous to_vector implementation). Seems that I have misunderstood the docs  the first time I read it.

- to_vector does not sort the vector by keys by default

* Fix polyglot hash maps method dispatch

* Add tests that effectively test hash code implementation.

Via hash map that behaves like a hash set.

* Remove Hashcode_Spec

* Add some polyglot tests

* Add Text.== tests for NFD normalization

* Fix NFD normalization bug in Text.java

* Improve performance of EqualsAnyNode.equalsTexts specialization

* Properly compute hash code for Atom and cache it

* Fix Text specialization in HashCodeAnyNode

* Add Hash_Map_Spec as part of all tests

* Remove HashMapTest.java

Providing all the infrastructure for all the needed Truffle nodes is no longer manageable.

* Remove rest of identityHashCode message implementations

* Replace old Map with Hash_Map

* Add some docs

* Add TruffleBoundaries

* Formatting

* Fix some tests to accept unsorted vector from Map.to_vector

* Delete Map.first and Map.last methods

* Add specialization for big integer hash

* Introduce proper HashCodeTest and EqualsTest.

- Use jUnit theories.
- Call nodes directly

* Fix some specializations for primitives in HashCodeAnyNode

* Fix host object specialization

* Remove Any.hash_code

* Fix import in Map.enso

* Update changelog

* Reformat

* Add truffle boundary to BigInteger.hashCode

* Fix performance of HashCodeTest - initialize DataPoints just once

* Fix MetaIsATest

* Fix ValuesGenerator.textual - Java's char is not Text

* Fix indent in Map_Spec.enso

* Add maps to datapoints in HashCodeTest

* Add specialization for maps in HashCodeAnyNode

* Add multiLevelAtoms to ValuesGenerator

* Provide a workaround for non-linear key inserts

* Fix specializations for double and BigInteger

* Cosmetics

* Add truffle boundaries

* Add allowInlining=true to some truffle boundaries.

Increases performance a lot.

* Increase the size of vectors, and warmup time for Vector.Distinct benchmark

* Various small performance fixes.

* Fix Geo_Spec tests to accept unsorted Map.to_vector

* Implement Map.remove

* FIx Visualization tests to accept unsorted Map.to_vector

* Treat java.util.Properties as Map

* Add truffle boundaries

* Invoke polyglot methods on java.util.Properties

* Ignore python tests if python lang is missing

CHANGELOG.md

@@ -429,6 +429,7 @@
 [3964]: https://github.com/enso-org/enso/pull/3964
 [3967]: https://github.com/enso-org/enso/pull/3967
 [3987]: https://github.com/enso-org/enso/pull/3987
+[3878]: https://github.com/enso-org/enso/pull/3878
 [3997]: https://github.com/enso-org/enso/pull/3997
 [4013]: https://github.com/enso-org/enso/pull/4013
 [4026]: https://github.com/enso-org/enso/pull/4026
@@ -514,6 +515,7 @@
 - [Sync language server with file system after VCS restore][4020]
 - [`ArrayOverBuffer` behaves like an `Array` and `Array.sort` no longer sorts in
   place][4022]
+- [Implement hashing functionality for all objects][3878]
 - [Introducing Meta.atom_with_hole][4023]
 - [Report failures in name resolution in type signatures][4030]
 - [Attach visualizations to sub-expressions][4048]

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Map.enso

@@ -1,181 +1,89 @@
-import project.Any.Any
 import project.Data.Numbers.Integer
-import project.Data.Ordering.Ordering
+import project.Data.Vector.Vector
-import project.Data.Map.Internal
 import project.Data.Pair.Pair
 import project.Data.Text.Text
-import project.Data.Vector.Vector
-import project.Error.Error
-import project.Error.No_Such_Key.No_Such_Key
-import project.Nothing.Nothing
 
 from project.Data.Boolean import Boolean, True, False
+from project import Error, Nothing, Any, Panic
+from project.Error.No_Such_Key import No_Such_Key
 
-## A key-value store. This type assumes all keys are pairwise comparable,
+
-   using the `<`, `>` and `==` operators.
+## A key-value store. It is possible to use any type as keys and values and mix them in
-type Map
+   one Map. Keys are checked for equality based on their hash code and `==` operator, which
+   is both an internal part of Enso. Enso is capable of computing a hash code, and checking
+   for equality any objects that can appear in Enso - primitives, Atoms, values coming from
+   different languages, etc.
+
+   A single key-value pair is called an *entry*.
+
+   It is possible to pass a Map created in Enso to foreign functions, where it will be treated
+   as appropriate map structures - in Python that is a dictionary, and in JavaScript, it is
+   a `Map`. And likewise, it is possible to pass a foreign map into Enso, where it will be
+   treated as a Map.
+@Builtin_Type
+type Map key value
     ## Returns an empty map.
-
-       > Example
-         Create an empty map.
-
-             import Standard.Base.Data.Map.Map
-
-             example_empty = Map.empty
     empty : Map
-    empty = Map.Tip
+    empty = @Builtin_Method "Map.empty"
 
-    ## Returns a single-element map with the given key and value present.
+    ## Returns a single-element map with the given key and value.
+       A Call to `Map.singleton key value` is the same as a call to
+       `Map.empty.insert key value`.
 
        Arguments:
-       - key: The key to update in the map.
+       - key: The key to to use for `value` in the map.
-       - value: The value to store against 'key' in the map.
+       - value: The value to store under 'key' in the map.
 
        > Example
-         Create a single element map storing the key 1 and the value 2.
+         Create a single element map storing the key "my_key" and the value 2.
 
              import Standard.Base.Data.Map.Map
 
-             example_singleton = Map.singleton 1 2
+             example_singleton = Map.singleton "my_key" 2
     singleton : Any -> Any -> Map
-    singleton key value = Map.Bin 1 key value Map.Tip Map.Tip
+    singleton key value = Map.empty.insert key value
 
-    ## Builds a map from a vector of key-value pairs.
+    ## Builds a map from a vector of key-value pairs, with each key-value pair
+       represented as a 2 element vector.
 
        Arguments:
-       - vec: A vector of key-value pairs.
+       - vec: A vector of key-value pairs (2 element vectors).
 
        > Example
          Building a map containing two key-value pairs.
 
              import Standard.Base.Data.Map.Map
 
-             example_from_vector = Map.from_vector [[1, 2], [3, 4]]
+             example_from_vector = Map.from_vector [["A", 1], ["B", 2]]
     from_vector : Vector Any -> Map
     from_vector vec = vec.fold Map.empty (m -> el -> m.insert (el.at 0) (el.at 1))
 
-    ## PRIVATE
+    ## Returns True iff the Map is empty, i.e., does not have any entries.
-       A key-value store. This type assumes all keys are pairwise comparable,
-       using the `<`, `>` and `==` operators.
-    Tip
-
-    ## PRIVATE
-       A key-value store. This type assumes all keys are pairwise comparable,
-       using the `<`, `>` and `==` operators.
-
-       Arguments:
-       - s: The size of the tree at this node.
-       - key: The key stored at this node.
-       - value: The value stored at this node.
-       - left: The left subtree.
-       - right: The right subtree.
-    Bin s key value left right
-
-    ## Checks if the map is empty.
-
-       > Example
-         Check if a map is empty.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_is_empty = Examples.map.is_empty
     is_empty : Boolean
-    is_empty self = case self of
+    is_empty self = self.size == 0
-        Map.Bin _ _ _ _ _ -> False
-        Map.Tip -> True
 
-    ## Checks if the map is not empty.
+    ## Returns True iff the Map is not empty, i.e., has at least one entry.
-
-       > Example
-         Check if a map is not empty.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_not_empty = Examples.map.not_empty
     not_empty : Boolean
     not_empty self = self.is_empty.not
 
     ## Returns the number of entries in this map.
-
-       > Example
-         Get the size of a map.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_size = Examples.map.size
     size : Integer
-    size self = case self of
+    size self = @Builtin_Method "Map.size"
-        Map.Bin s _ _ _ _ -> s
-        Map.Tip -> 0
-
-    ## Converts the map into a vector of `[key, value]` pairs.
-
-       The returned vector is sorted in the increasing order of keys.
-
-       > Example
-         Convert a map to a vector.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_to_vector = Examples.map.to_vector
-    to_vector : Vector Any
-    to_vector self =
-        builder = Vector.new_builder
-        to_vector_with_builder m = case m of
-            Map.Bin _ k v l r ->
-                to_vector_with_builder l
-                builder.append [k, v]
-                to_vector_with_builder r
-                Nothing
-            Map.Tip -> Nothing
-        to_vector_with_builder self
-        result = builder.to_vector
-        result
-
-    ## Returns a text representation of this map.
-
-       > Example
-         Convert a map to text.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_to_text = Examples.map.to_text
-    to_text : Text
-    to_text self = self.to_vector.to_text
-
-    ## Checks if this map is equal to another map.
-
-       Arguments:
-       - that: The map to compare `self` to.
-
-       Maps are equal when they contained the same keys and the values
-       associated with each key are pairwise equal.
-
-       > Example
-         Checking two maps for equality.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_equals =
-                other = Map.empty . insert 1 "one" . insert 3 "three" . insert 5 "five"
-                Examples.map == other
-    == : Map -> Boolean
-    == self that = case that of
-        _ : Map -> self.to_vector == that.to_vector
-        _ -> False
 
     ## Inserts a key-value mapping into this map, overriding any existing
        instance of `key` with the new `value`.
 
+       Note that since the return type is also a `Map`, multiple `insert`
+       calls can be chained, e.g., `map.insert "A" 1 . insert "B" 2`.
+
+       Due to the limitation of the current implementation, inserts with a
+       key that is already contained in the map, or insert on a map instance that
+       is re-used in other computations, have a linear time complexity.
+       For all the other cases, the time complexity of this method is constant.
+
        Arguments:
        - key: The key to insert the value for.
-       - value: The value to associate with `key`.
+       - value: The value to associate with the `key`.
 
        > Example
          Insert the value "seven" into the map for the key 7.
@@ -185,27 +93,50 @@ type Map
 
              example_insert = Examples.map.insert 7 "seven"
     insert : Any -> Any -> Map
-    insert self key value = Internal.insert self key value
+    insert self key value = @Builtin_Method "Map.insert"
 
-    ## Gets the value associated with `key` in this map, or throws a
+    ## Removes an entry specified by the given key from this map, and
-       `No_Such_Key.Error` if `key` is not present.
+       returns a new map without this entry. Throw `No_Such_Key.Error`
+       if `key` is not present.
 
        Arguments:
        - key: The key to look up in the map.
 
        > Example
-         Get the value for the key 1 in a map.
+         Remove key "A" from a map
+
+             import Standard.Data.Map.Map
+
+             Examples.map.remove "A"
+
+    remove : Any -> Map ! No_Such_Key
+    remove self key =
+        Panic.catch Any (self.remove_builtin key) _->
+            Error.throw No_Such_Key.Error self key
+
+    ## Gets the value associated with `key` in this map, or throws a
+       `No_Such_Key.Error` if `key` is not present.
+
+       This method has a constant time complexity.
+
+       Arguments:
+       - key: The key to look up in the map.
+
+       > Example
+         Looks up the value for the key "A" in a map.
 
              import Standard.Base.Data.Map.Map
              import Standard.Examples
 
-             example_at = Examples.map.at 1
+             example_at = Examples.map.at "A"
     at : Any -> Any ! No_Such_Key
     at self key = self.get key (Error.throw (No_Such_Key.Error self key))
 
     ## Gets the value associated with `key` in this map, or returns
        `if_missing` if it isn't present.
 
+       This method has a constant time complexity.
+
        Arguments:
        - key: The key to look up in the map.
        - if_missing: The value to use if the key isn't present.
@@ -219,57 +150,19 @@ type Map
 
              example_get = Examples.map.get 2 "zero"
     get : Any -> Any -> Any
-    get self key ~if_missing=Nothing =
+    get self key ~if_missing=Nothing = self.get_builtin key if_missing
-        go map = case map of
-            Map.Tip -> if_missing
-            Map.Bin _ k v l r -> case Internal.compare_allow_nothing key k of
-                Ordering.Equal -> v
-                Ordering.Less -> @Tail_Call go l
-                Ordering.Greater -> @Tail_Call go r
-        result = go self
-        result
 
-    ## Checks if a key is in the map.
+    ## Returns True iff the Map contains the given `key`.
-
-       Arguments:
-       - key: The key to look up in the map.
-
-       > Example
-         Checks the key 2 is in a map.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_contains = Examples.map.contains_key 2
     contains_key : Any -> Boolean
-    contains_key self key =
+    contains_key self key = @Builtin_Method "Map.contains_key"
-        go map = case map of
-            Map.Tip -> False
-            Map.Bin _ k _ l r -> case Internal.compare_allow_nothing key k of
-                Ordering.Equal -> True
-                Ordering.Less -> @Tail_Call go l
-                Ordering.Greater -> @Tail_Call go r
-        go self
 
-    ## Transforms the map's keys and values to create a new map.
+    ## Returns an unsorted vector of all the keys in this Map.
+    keys : Vector Any
+    keys self = self.to_vector.map pair-> pair.at 0
 
-       Arguments:
+    ## Returns an unsorted vector of all the values in this Map.
-       - function: The function used to transform the map, taking a key and a
+    values : Vector Any
-         value and returning a pair of `[key, value]`.
+    values self = self.to_vector.map pair-> pair.at 1
-
-       > Example
-         Turn all keys into `Text` and append "_word" to the values in the map.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_transform =
-                Examples.map.transform (k -> v -> [k.to_text, v + "_word"])
-    transform : (Any -> Any -> [Any, Any]) -> Map
-    transform self function =
-        func_pairs = p -> function (p.at 0) (p.at 1)
-        vec_transformed = self.to_vector.map func_pairs
-        Map.from_vector vec_transformed
 
     ## Maps a function over each value in this map.
 
@@ -306,11 +199,10 @@ type Map
                 Examples.map.map_with_key (k -> v -> k.to_text + "-" + v)
     map_with_key : (Any -> Any -> Any) -> Map
     map_with_key self function =
-        go map = case map of
+        Map.from_vector <| self.to_vector.map pair->
-            Map.Bin s k v l r ->
+            key = pair.first
-                Map.Bin s k (function k v) (go l) (go r)
+            value = pair.last
-            Map.Tip -> Map.Tip
+            [key, (function key value)]
-        go self
 
     ## Maps a function over each key in this map.
 
@@ -330,6 +222,62 @@ type Map
         trans_function = k -> v -> [function k, v]
         self.transform trans_function
 
+    ## Transforms the map's keys and values to create a new map.
+
+       Arguments:
+       - function: The function used to transform the map, taking a key and a
+         value and returning a pair of `[key, value]`.
+
+       > Example
+         Turn all keys into `Text` and append "_word" to the values in the map.
+
+             import Standard.Base.Data.Map.Map
+             import Standard.Examples
+
+             example_transform =
+                Examples.map.transform (k -> v -> [k.to_text, v + "_word"])
+    transform : (Any -> Any -> [Any, Any]) -> Map
+    transform self function =
+        func_pairs = p -> function (p.at 0) (p.at 1)
+        vec_transformed = self.to_vector.map func_pairs
+        Map.from_vector vec_transformed
+
+    ## Combines the values in the map.
+
+       Arguments:
+       - init: The initial value for the fold.
+       - function: A binary function to apply to pairs of values in the map.
+
+       > Example
+         Find the length of the longest word in the map.
+
+             import Standard.Base.Data.Map.Map
+             import Standard.Examples
+
+             example_fold = Examples.map.fold 0 (l -> r -> Math.max l r.length)
+    fold : Any -> (Any -> Any -> Any) -> Any
+    fold self init function = self.values.fold init function
+
+    ## Combines the key-value pairs in the map.
+
+       Arguments:
+       - init: The initial value for the fold.
+       - function: A function taking the left value, the current key, and the
+         current value, and combining them to yield a single value.
+
+       > Example
+         Glue the values in the map together with the keys.
+
+             import Standard.Base.Data.Map.Map
+             import Standard.Examples
+
+             example_fold_with_key =
+                Examples.map.fold_with_key "" (l -> k -> v -> l + k.to_text + v)
+    fold_with_key : Any -> (Any -> Any -> Any -> Any) -> Any
+    fold_with_key self init function =
+        self.to_vector.fold init acc-> pair->
+            function acc pair.first pair.last
+
     ## Applies a function to each value in the map.
 
        Arguments:
@@ -371,121 +319,20 @@ type Map
                 IO.println v
     each_with_key : (Any -> Any -> Any) -> Nothing
     each_with_key self function =
-        go map = case map of
+        self.to_vector.each pair->
-            Map.Bin _ k v l r ->
+            function pair.first pair.last
-                go l
-                function k v
-                go r
-                Nothing
-            Map.Tip -> Nothing
-        go self
 
-    ## Combines the values in the map.
+    ## Returns an unsorted vector of key-value pairs (nested 2 element vectors).
+       `Map.from_vector` method is an inverse method, so the following expression
+       is true for all maps: `Map.from_vector map.to_vector == map`.
+    to_vector : Vector Any
+    to_vector self = @Builtin_Method "Map.to_vector"
 
-       Arguments:
+    ## Returns a text representation of this Map.
-       - init: The initial value for the fold.
+    to_text : Text
-       - function: A binary function to apply to pairs of values in the map.
+    to_text self = @Builtin_Method "Map.to_text"
 
-       > Example
+    ## PRIVATE
-         Find the length of the longest word in the map.
+    get_builtin : Any -> Any -> Any
+    get_builtin self key ~if_missing = @Builtin_Method "Map.get_builtin"
 
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_fold = Examples.map.fold 0 (l -> r -> Math.max l r.length)
-    fold : Any -> (Any -> Any -> Any) -> Any
-    fold self init function =
-        go map init = case map of
-            Map.Bin _ _ v l r ->
-                y = go l init
-                z = function y v
-                go r z
-            Map.Tip -> init
-        go self init
-
-    ## Combines the key-value pairs in the map.
-
-       Arguments:
-       - init: The initial value for the fold.
-       - function: A function taking the left value, the current key, and the
-         current value, and combining them to yield a single value.
-
-       > Example
-         Glue the values in the map together with the keys.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_fold_with_key =
-                Examples.map.fold_with_key "" (l -> k -> v -> l + k.to_text + v)
-    fold_with_key : Any -> (Any -> Any -> Any -> Any) -> Any
-    fold_with_key self init function =
-        go map init = case map of
-            Map.Bin _ k v l r ->
-                y = go l init
-                z = function y k v
-                go r z
-            Map.Tip -> init
-        go self init
-
-    ## Get a vector containing the keys in the map.
-
-       > Example
-         Get the keys from the map `m`.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_keys = Examples.map.keys
-    keys : Vector
-    keys self =
-        builder = Vector.new_builder
-        to_vector_with_builder m = case m of
-            Map.Bin _ k _ l r ->
-                to_vector_with_builder l
-                builder.append k
-                to_vector_with_builder r
-                Nothing
-            Map.Tip -> Nothing
-        to_vector_with_builder self
-        builder.to_vector
-
-    ## Get a vector containing the values in the map.
-
-       > Example
-         Get the values from the map `m`.
-
-             import Standard.Base.Data.Map.Map
-             import Standard.Examples
-
-             example_values = Examples.map.values
-    values : Vector
-    values self =
-        builder = Vector.new_builder
-        to_vector_with_builder m = case m of
-            Map.Bin _ _ v l r ->
-                to_vector_with_builder l
-                builder.append v
-                to_vector_with_builder r
-                Nothing
-            Map.Tip -> Nothing
-        to_vector_with_builder self
-        builder.to_vector
-
-    ## Get a key value pair of the lowest key in the map.
-       If the map is empty, returns Nothing.
-    first : Pair
-    first self =
-        first p m = case m of
-            Map.Bin _ k v l _ -> @Tail_Call first (Pair.new k v) l
-            Map.Tip -> p
-        first Nothing self
-
-    ## Get a key value pair of the highest key in the map.
-       If the map is empty, returns Nothing.
-    last : Pair
-    last self =
-        last p m = case m of
-            Map.Bin _ k v _ r -> @Tail_Call last (Pair.new k v) r
-            Map.Tip -> p
-        last Nothing self

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Map/Internal.enso

@@ -1,164 +0,0 @@
-import project.Any.Any
-import project.Data.Map.Map
-import project.Data.Numbers.Integer
-import project.Data.Ordering.Ordering
-
-## PRIVATE
-   Compares keys allowing for the possibility that one or both keys are Nothing.
-compare_allow_nothing : Any -> Any -> Ordering
-compare_allow_nothing x y = if x == y then Ordering.Equal else
-    if x.is_nothing then Ordering.Less else
-        if y.is_nothing then Ordering.Greater else
-            x.compare_to y
-
-## PRIVATE
-
-   A helper used in the insert operation to insert into the left subtree.
-
-   Arguments:
-   - key: The key to insert.
-   - value: The value to insert.
-   - k: The previous top key of the left subtree.
-   - v: The previous top value of the left subtree.
-   - l: The left subtree.
-   - r: The right subtree.
-insert_l : Any -> Any -> Any -> Any -> Map -> Map -> Map
-insert_l key value k v l r =
-    new_left = insert l key value
-    balance_left k v new_left r
-
-## PRIVATE
-
-   A helper used in the insert operation to insert into the right subtree.
-
-   Arguments:
-   - key: The key to insert.
-   - value: The value to insert.
-   - k: The previous top key of the right subtree.
-   - v: The previous top value of the right subtree.
-   - l: The left subtree.
-   - r: The right subtree.
-insert_r : Any -> Any -> Any -> Any -> Map -> Map -> Map
-insert_r key value k v l r =
-    new_right = insert r key value
-    balance_right k v l new_right
-
-## PRIVATE
-
-   Helper for inserting a new key-value pair into a map.
-
-   Arguments:
-   - map: The map into which the insertion is performed.
-   - key: The key for which to insert the value into the map.
-   - value: The value to insert into the map at the given key.
-
-   The algorithm used here is based on the paper "Implementing Sets Efficiently
-   in a Functional Language" by Stephen Adams.  The implementation is based on
-   Haskell's `Data.Map.Strict` as implemented in the `containers` package.
-insert : Map -> Any -> Any -> Map
-insert map key value = case map of
-    Map.Bin s k v l r -> case compare_allow_nothing key k of
-        Ordering.Less -> @Tail_Call insert_l key value k v l r
-        Ordering.Greater -> @Tail_Call insert_r key value k v l r
-        Ordering.Equal -> Map.Bin s key value l r
-    _ -> Map.Bin 1 key value Map.Tip Map.Tip
-
-## PRIVATE
-
-   Re-balances the map after the left subtree grows.
-
-   Arguments:
-   - k: The old top key of the left subtree.
-   - x: The old top value of the left subtree.
-   - l: The left subtree.
-   - r: The right subtree.
-balance_left : Any -> Any -> Map -> Map -> Map
-balance_left k x l r = case r of
-    Map.Bin rs _ _ _ _ -> case l of
-        Map.Bin ls lk lx ll lr ->
-            if ls <= delta*rs then Map.Bin 1+ls+rs k x l r else
-                lls = size ll
-                case lr of
-                    Map.Bin lrs lrk lrx lrl lrr ->
-                        if lrs < ratio*lls then Map.Bin 1+ls+rs lk lx ll (Map.Bin 1+rs+lrs k x lr r) else
-                            lrls = size lrl
-                            lrrs = size lrr
-                            Map.Bin 1+ls+rs lrk lrx (Map.Bin 1+lls+lrls lk lx ll lrl) (Map.Bin 1+rs+lrrs k x lrr r)
-        _ -> Map.Bin 1+rs k x Map.Tip r
-    _ -> case l of
-        Map.Tip -> Map.Bin 1 k x Map.Tip Map.Tip
-        Map.Bin _ _ _ Map.Tip Map.Tip -> Map.Bin 2 k x l Map.Tip
-        Map.Bin _ lk lx Map.Tip (Map.Bin _ lrk lrx _ _) -> Map.Bin 3 lrk lrx (Map.Bin 1 lk lx Map.Tip Map.Tip) (Map.Bin 1 k x Map.Tip Map.Tip)
-        Map.Bin _ lk lx ll Map.Tip -> Map.Bin 3 lk lx ll (Map.Bin 1 k x Map.Tip Map.Tip)
-        Map.Bin ls lk lx ll lr -> case lr of
-            Map.Bin lrs lrk lrx lrl lrr ->
-                lls = size ll
-                if lrs < ratio*lls then Map.Bin 1+ls lk lx ll (Map.Bin 1+lrs k x lr Map.Tip) else
-                    lrls = size lrl
-                    lrrs = size lrr
-                    Map.Bin 1+ls lrk lrx (Map.Bin 1+lls+lrls lk lx ll lrl) (Map.Bin 1+lrrs k x lrr Map.Tip)
-
-## PRIVATE
-
-   Re-balances the map after the right subtree grows.
-
-   Arguments:
-   - k: The old top key of the right subtree.
-   - x: The old top value of the right subtree.
-   - l: The left subtree.
-   - r: The right subtree.
-balance_right : Any -> Any -> Map -> Map -> Map
-balance_right k x l r = case l of
-    Map.Bin ls _ _ _ _ -> case r of
-        Map.Bin rs rk rx rl rr ->
-            if rs <= delta*ls then Map.Bin 1+ls+rs k x l r else
-                case rl of
-                    Map.Bin rls rlk rlx rll rlr ->
-                        rrs = size rr
-                        if rls < ratio*rrs then Map.Bin 1+ls+rs rk rx (Map.Bin 1+ls+rls k x l rl) rr else
-                            rlls = size rll
-                            rlrs = size rlr
-                            Map.Bin 1+ls+rs rlk rlx (Map.Bin 1+ls+rlls k x l rll) (Map.Bin 1+rrs+rlrs rk rx rlr rr)
-        _ -> Map.Bin 1+ls k x l Map.Tip
-    _ -> case r of
-        Map.Tip -> Map.Bin 1 k x Map.Tip Map.Tip
-        Map.Bin _ _ _ Map.Tip Map.Tip -> Map.Bin 2 k x Map.Tip r
-        Map.Bin _ rk rx Map.Tip rr -> Map.Bin 3 rk rx (Map.Bin 1 k x Map.Tip Map.Tip) rr
-        Map.Bin _ rk rx (Map.Bin _ rlk rlx _ _) Map.Tip -> Map.Bin 3 rlk rlx (Map.Bin 1 k x Map.Tip Map.Tip) (Map.Bin 1 rk rx Map.Tip Map.Tip)
-        Map.Bin rs rk rx rl rr -> case rl of
-            Map.Bin rls rlk rlx rll rlr -> case rr of
-                Map.Bin rrs _ _ _ _ ->
-                    if rls < ratio*rrs then Map.Bin 1+rs rk rx (Map.Bin 1+rls k x Map.Tip rl) rr else
-                        srll = size rll
-                        srlr = size rlr
-                        Map.Bin 1+rs rlk rlx (Map.Bin 1+srll k x Map.Tip rll) (Map.Bin 1+rrs+srlr rk rx rlr rr)
-
-## PRIVATE
-
-   Controls the difference between inner and outer siblings of a heavy subtree.
-   Used to decide between a double and a single rotation.
-
-   The choice of values for `ratio` and `delta` is taken from the Haskell
-   implementation.
-ratio : Integer
-ratio = 2
-
-## PRIVATE
-
-   Controls the maximum size difference between subtrees.
-
-   The choice of values for `ratio` and `delta` is taken from the Haskell
-   implementation.
-delta : Integer
-delta = 3
-
-## PRIVATE
-
-   Gets the size of a map.
-
-   Arguments:
-   - m: The map to get the size of.
-size : Map -> Integer
-size m = case m of
-    Map.Bin s _ _ _ _ -> s
-    _ -> 0

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Text/Encoding.enso

@@ -15,8 +15,7 @@ type Encoding
        Used to provide auto completion in the UI.
     all_character_sets : Vector Text
     all_character_sets =
-        java_array = Charset.availableCharsets.keySet.toArray
+        Charset.availableCharsets.keys
-        Vector.from_polyglot_array java_array
 
     ## Get all available Encodings.
     all_encodings : Vector Encoding

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Text/Text_Ordering.enso

@@ -27,7 +27,7 @@ type Text_Ordering
          this to `True` results in a "Natural" ordering.
     Case_Sensitive (sort_digits_as_numbers:Boolean=False)
 
-    ## Case sensitive ordering of values.
+    ## Case insensitive ordering of values.
 
        It will ensure case-insensitive ordering regardless of backend defaults.
        This may make database queries more complicated and may result in being

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Time/Time_Zone.enso

@@ -99,9 +99,9 @@ type Time_Zone
        > Example
          Get time zone 1 hour 1 minute and 50 seconds from UTC.
 
-             from Standard.Base import Zone
+             from Standard.Base.Time.Time_Zone import Time_Zone
 
-             example_new = Zone.new 1 1 50
+             example_new = Time_Zone.new 1 1 50
     new : Integer -> Integer -> Integer -> Time_Zone
     new (hours = 0) (minutes = 0) (seconds = 0) =
         new_builtin hours minutes seconds

distribution/lib/Standard/Database/0.0.0-dev/src/Internal/JDBC_Connection.enso

@@ -138,8 +138,9 @@ create : Text -> Vector -> JDBC_Connection
 create url properties = handle_sql_errors <|
     java_props = Properties.new
     properties.each pair->
-        if pair.second.is_nothing.not then java_props.setProperty pair.first pair.second else
+        case pair.second of
-            java_props.remove pair.first
+            Nothing -> Polyglot.invoke java_props "remove" [pair.first]
+            _ -> Polyglot.invoke java_props "setProperty" [pair.first, pair.second]
     java_connection = JDBCProxy.getConnection url java_props
 
     resource = Managed_Resource.register java_connection close_connection

engine/runtime-language-epb/src/main/java/org/enso/interpreter/epb/runtime/PolyglotProxy.java

@@ -9,6 +9,7 @@ import com.oracle.truffle.api.interop.InteropLibrary;
 import com.oracle.truffle.api.interop.InvalidArrayIndexException;
 import com.oracle.truffle.api.interop.TruffleObject;
 import com.oracle.truffle.api.interop.UnknownIdentifierException;
+import com.oracle.truffle.api.interop.UnknownKeyException;
 import com.oracle.truffle.api.interop.UnsupportedMessageException;
 import com.oracle.truffle.api.interop.UnsupportedTypeException;
 import com.oracle.truffle.api.library.CachedLibrary;
@@ -422,6 +423,131 @@ public final class PolyglotProxy implements TruffleObject {
     }
   }
 
+  @ExportMessage
+  public boolean hasHashEntries(
+      @CachedLibrary("this.delegate") InteropLibrary hashMaps,
+      @CachedLibrary("this") InteropLibrary node,
+      @CachedLibrary(limit = "5") InteropLibrary errors,
+      @Cached @Cached.Exclusive ContextRewrapExceptionNode contextRewrapExceptionNode,
+      @Cached @Cached.Exclusive BranchProfile profile) {
+    Object p = enterOrigin(node);
+    try {
+      return hashMaps.hasHashEntries(this.delegate);
+    } catch (Throwable e) {
+      profile.enter();
+      if (errors.isException(e)) {
+        // `isException` means this must be AbstractTruffleException
+        //noinspection ConstantConditions
+        throw contextRewrapExceptionNode.execute((AbstractTruffleException) e, origin, target);
+      } else {
+        throw e;
+      }
+    } finally {
+      leaveOrigin(node, p);
+    }
+  }
+
+  @ExportMessage
+  public long getHashSize(
+      @CachedLibrary("this.delegate") InteropLibrary hashes,
+      @CachedLibrary("this") InteropLibrary node,
+      @CachedLibrary(limit = "5") InteropLibrary errors,
+      @Cached @Cached.Exclusive ContextRewrapExceptionNode contextRewrapExceptionNode,
+      @Cached @Cached.Exclusive BranchProfile profile)
+      throws UnsupportedMessageException {
+    Object p = enterOrigin(node);
+    try {
+      return hashes.getHashSize(this.delegate);
+    } catch (Throwable e) {
+      profile.enter();
+      if (errors.isException(e)) {
+        // `isException` means this must be AbstractTruffleException
+        //noinspection ConstantConditions
+        throw contextRewrapExceptionNode.execute((AbstractTruffleException) e, origin, target);
+      } else {
+        throw e;
+      }
+    } finally {
+      leaveOrigin(node, p);
+    }
+  }
+
+  @ExportMessage
+  public boolean isHashEntryReadable(
+      Object key,
+      @CachedLibrary("this.delegate") InteropLibrary hashes,
+      @CachedLibrary("this") InteropLibrary node,
+      @CachedLibrary(limit = "5") InteropLibrary errors,
+      @Cached @Cached.Exclusive ContextRewrapExceptionNode contextRewrapExceptionNode,
+      @Cached @Cached.Exclusive BranchProfile profile) {
+    Object p = enterOrigin(node);
+    try {
+      return hashes.isHashEntryReadable(this.delegate, key);
+    } catch (Throwable e) {
+      profile.enter();
+      if (errors.isException(e)) {
+        // `isException` means this must be AbstractTruffleException
+        //noinspection ConstantConditions
+        throw contextRewrapExceptionNode.execute((AbstractTruffleException) e, origin, target);
+      } else {
+        throw e;
+      }
+    } finally {
+      leaveOrigin(node, p);
+    }
+  }
+
+  @ExportMessage
+  public Object readHashValue(
+      Object key,
+      @CachedLibrary("this.delegate") InteropLibrary hashes,
+      @CachedLibrary("this") InteropLibrary node,
+      @CachedLibrary(limit = "5") InteropLibrary errors,
+      @Cached @Cached.Exclusive ContextRewrapExceptionNode contextRewrapExceptionNode,
+      @Cached @Cached.Exclusive BranchProfile profile)
+      throws UnsupportedMessageException, UnknownKeyException {
+    Object p = enterOrigin(node);
+    try {
+      return hashes.readHashValue(this.delegate, key);
+    } catch (Throwable e) {
+      profile.enter();
+      if (errors.isException(e)) {
+        // `isException` means this must be AbstractTruffleException
+        //noinspection ConstantConditions
+        throw contextRewrapExceptionNode.execute((AbstractTruffleException) e, origin, target);
+      } else {
+        throw e;
+      }
+    } finally {
+      leaveOrigin(node, p);
+    }
+  }
+
+  @ExportMessage
+  public Object getHashEntriesIterator(
+      @CachedLibrary("this.delegate") InteropLibrary hashes,
+      @CachedLibrary("this") InteropLibrary node,
+      @CachedLibrary(limit = "5") InteropLibrary errors,
+      @Cached @Cached.Exclusive ContextRewrapExceptionNode contextRewrapExceptionNode,
+      @Cached @Cached.Exclusive BranchProfile profile)
+      throws UnsupportedMessageException {
+    Object p = enterOrigin(node);
+    try {
+      return hashes.getHashEntriesIterator(this.delegate);
+    } catch (Throwable e) {
+      profile.enter();
+      if (errors.isException(e)) {
+        // `isException` means this must be AbstractTruffleException
+        //noinspection ConstantConditions
+        throw contextRewrapExceptionNode.execute((AbstractTruffleException) e, origin, target);
+      } else {
+        throw e;
+      }
+    } finally {
+      leaveOrigin(node, p);
+    }
+  }
+
   @ExportMessage
   public boolean isString(
       @CachedLibrary("this.delegate") InteropLibrary strings,

engine/runtime/src/main/java/org/enso/interpreter/node/callable/InvokeMethodNode.java

@@ -272,6 +272,28 @@ public abstract class InvokeMethodNode extends BaseNode {
     return invokeFunctionNode.execute(function, frame, state, arguments);
   }
 
+  @Specialization(
+      guards = {
+        "!types.hasType(self)",
+        "!types.hasSpecialDispatch(self)",
+        "getPolyglotCallType(self, symbol, interop, methodResolverNode) == CONVERT_TO_HASH_MAP",
+      })
+  Object doConvertHashMap(
+      VirtualFrame frame,
+      State state,
+      UnresolvedSymbol symbol,
+      Object self,
+      Object[] arguments,
+      @CachedLibrary(limit = "10") InteropLibrary interop,
+      @CachedLibrary(limit = "10") TypesLibrary types,
+      @Cached MethodResolverNode methodResolverNode) {
+    var ctx = EnsoContext.get(this);
+    var hashMapType = ctx.getBuiltins().map();
+    var function = methodResolverNode.expectNonNull(self, hashMapType, symbol);
+    arguments[0] = self;
+    return invokeFunctionNode.execute(function, frame, state, arguments);
+  }
+
   @Specialization(
       guards = {
         "!types.hasType(self)",

engine/runtime/src/main/java/org/enso/interpreter/node/callable/resolver/HostMethodCallNode.java

@@ -80,6 +80,11 @@ public abstract class HostMethodCallNode extends Node {
      * Standard.Base.Data.Time.Time_Zone} and dispatching natively.
      */
     CONVERT_TO_TIME_ZONE,
+    /**
+     * The method call should be handled by converting {@code self} to a {@code
+     * Standard.Base.Data.Map} and dispatching natively.
+     */
+    CONVERT_TO_HASH_MAP,
     /** The method call should be handled by dispatching through the {@code Any} type. */
     NOT_SUPPORTED;
 
@@ -99,7 +104,8 @@ public abstract class HostMethodCallNode extends Node {
           && this != CONVERT_TO_DURATION
           && this != CONVERT_TO_ZONED_DATE_TIME
           && this != CONVERT_TO_TIME_OF_DAY
-          && this != CONVERT_TO_TIME_ZONE;
+          && this != CONVERT_TO_TIME_ZONE
+          && this != CONVERT_TO_HASH_MAP;
     }
   }
 
@@ -163,6 +169,8 @@ public abstract class HostMethodCallNode extends Node {
           return PolyglotCallType.CONVERT_TO_ARRAY;
         }
       }
+    } else if (library.hasHashEntries(self)) {
+      return PolyglotCallType.CONVERT_TO_HASH_MAP;
     }
 
     String methodName = symbol.getName();

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/meta/EqualsAnyNode.java

@@ -1,6 +1,7 @@
 package org.enso.interpreter.node.expression.builtin.meta;
 
 import com.ibm.icu.text.Normalizer;
+import com.ibm.icu.text.Normalizer2;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Fallback;
@@ -9,7 +10,9 @@ import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.interop.ArityException;
 import com.oracle.truffle.api.interop.InteropLibrary;
 import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.StopIterationException;
 import com.oracle.truffle.api.interop.UnknownIdentifierException;
+import com.oracle.truffle.api.interop.UnknownKeyException;
 import com.oracle.truffle.api.interop.UnsupportedMessageException;
 import com.oracle.truffle.api.interop.UnsupportedTypeException;
 import com.oracle.truffle.api.library.CachedLibrary;
@@ -31,6 +34,7 @@ import org.enso.interpreter.runtime.callable.atom.Atom;
 import org.enso.interpreter.runtime.callable.atom.AtomConstructor;
 import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.data.Type;
+import org.enso.interpreter.runtime.data.text.Text;
 import org.enso.interpreter.runtime.error.WarningsLibrary;
 import org.enso.interpreter.runtime.number.EnsoBigInteger;
 import org.enso.interpreter.runtime.state.State;
@@ -157,18 +161,46 @@ public abstract class EqualsAnyNode extends Node {
     }
   }
 
+  @Specialization(limit = "3")
+  boolean equalsTexts(Text selfText, Text otherText,
+      @CachedLibrary("selfText") InteropLibrary selfInterop,
+      @CachedLibrary("otherText") InteropLibrary otherInterop) {
+    if (selfText.is_normalized() && otherText.is_normalized()) {
+      return selfText.toString().compareTo(otherText.toString()) == 0;
+    } else {
+      return equalsStrings(selfText, otherText, selfInterop, otherInterop);
+    }
+  }
+
   /** Interop libraries **/
 
   @Specialization(guards = {
-      "selfInterop.isNull(selfNull)",
+      "selfInterop.isNull(selfNull) || otherInterop.isNull(otherNull)",
-      "otherInterop.isNull(otherNull)"
   }, limit = "3")
   boolean equalsNull(
       Object selfNull, Object otherNull,
       @CachedLibrary("selfNull") InteropLibrary selfInterop,
       @CachedLibrary("otherNull") InteropLibrary otherInterop
   ) {
-    return true;
+    return selfInterop.isNull(selfNull) && otherInterop.isNull(otherNull);
+  }
+
+  @Specialization(guards = {
+      "isHostObject(selfHostObject)",
+      "isHostObject(otherHostObject)",
+  })
+  boolean equalsHostObjects(
+      Object selfHostObject, Object otherHostObject,
+      @CachedLibrary(limit = "5") InteropLibrary interop
+  ) {
+    try {
+      return interop.asBoolean(
+          interop.invokeMember(selfHostObject, "equals", otherHostObject)
+      );
+    } catch (UnsupportedMessageException | ArityException | UnknownIdentifierException |
+             UnsupportedTypeException e) {
+      throw new IllegalStateException(e);
+    }
   }
 
   @Specialization(guards = {
@@ -373,6 +405,43 @@ public abstract class EqualsAnyNode extends Node {
     }
   }
 
+  @Specialization(guards = {
+      "selfInterop.hasHashEntries(selfHashMap)",
+      "otherInterop.hasHashEntries(otherHashMap)"
+  }, limit = "3")
+  boolean equalsHashMaps(Object selfHashMap, Object otherHashMap,
+      @CachedLibrary("selfHashMap") InteropLibrary selfInterop,
+      @CachedLibrary("otherHashMap") InteropLibrary otherInterop,
+      @CachedLibrary(limit = "5") InteropLibrary entriesInterop,
+      @Cached EqualsAnyNode equalsNode) {
+    try {
+      int selfHashSize = (int) selfInterop.getHashSize(selfHashMap);
+      int otherHashSize = (int) otherInterop.getHashSize(otherHashMap);
+      if (selfHashSize != otherHashSize) {
+        return false;
+      }
+      Object selfEntriesIter = selfInterop.getHashEntriesIterator(selfHashMap);
+      while (entriesInterop.hasIteratorNextElement(selfEntriesIter)) {
+        Object selfKeyValue = entriesInterop.getIteratorNextElement(selfEntriesIter);
+        Object key = entriesInterop.readArrayElement(selfKeyValue, 0);
+        Object selfValue = entriesInterop.readArrayElement(selfKeyValue, 1);
+        if (otherInterop.isHashEntryExisting(otherHashMap, key)
+            && otherInterop.isHashEntryReadable(otherHashMap, key)) {
+          Object otherValue = otherInterop.readHashValue(otherHashMap, key);
+          if (!equalsNode.execute(selfValue, otherValue)) {
+            return false;
+          }
+        } else {
+          return false;
+        }
+      }
+      return true;
+    } catch (UnsupportedMessageException | StopIterationException | UnknownKeyException |
+             InvalidArrayIndexException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
   /** Equals for Atoms and AtomConstructors */
 
   @Specialization
@@ -534,24 +603,13 @@ public abstract class EqualsAnyNode extends Node {
   @TruffleBoundary
   boolean equalsGeneric(Object left, Object right,
       @CachedLibrary(limit = "5") InteropLibrary interop) {
-    EnsoContext ctx = EnsoContext.get(interop);
-    if (isHostObject(ctx, left) && isHostObject(ctx, right)) {
-      try {
-        return interop.asBoolean(
-            interop.invokeMember(left, "equals", right)
-        );
-      } catch (UnsupportedMessageException | ArityException | UnknownIdentifierException |
-               UnsupportedTypeException e) {
-        throw new IllegalStateException(e);
-      }
-    } else {
       return left == right
-          || left.equals(right)
+          || interop.isIdentical(left, right, interop)
-          || interop.isIdentical(left, right, interop);
+          || left.equals(right);
-    }
   }
 
-  private static boolean isHostObject(EnsoContext context, Object object) {
+  @TruffleBoundary
-    return context.getEnvironment().isHostObject(object);
+  boolean isHostObject(Object object) {
+    return EnsoContext.get(this).getEnvironment().isHostObject(object);
   }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/meta/HashCodeAnyNode.java

@@ -0,0 +1,393 @@
+package org.enso.interpreter.node.expression.builtin.meta;
+
+import com.ibm.icu.text.Normalizer2;
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.GenerateUncached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.ArityException;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.StopIterationException;
+import com.oracle.truffle.api.interop.UnknownIdentifierException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.interop.UnsupportedTypeException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import com.oracle.truffle.api.profiles.ConditionProfile;
+import com.oracle.truffle.api.profiles.LoopConditionProfile;
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.time.ZonedDateTime;
+import java.util.Arrays;
+import org.enso.interpreter.dsl.AcceptsError;
+import org.enso.interpreter.node.expression.builtin.number.utils.BigIntegerOps;
+import org.enso.interpreter.runtime.EnsoContext;
+import org.enso.interpreter.runtime.callable.atom.Atom;
+import org.enso.interpreter.runtime.callable.atom.AtomConstructor;
+import org.enso.interpreter.runtime.data.text.Text;
+import org.enso.interpreter.runtime.error.WarningsLibrary;
+import org.enso.interpreter.runtime.number.EnsoBigInteger;
+
+/**
+ * Implements {@code hash_code} functionality.
+ *
+ * <p>Make sure that the hashing contract is retained after any modification.
+ *
+ * <h3>Hashing contract:</h3>
+ *
+ * <ul>
+ *   <li>Whenever two objects are equal ({@code EqualsAnyNode} returns {@code true}), their hashcode
+ *       should equal. More formally: {@code For all objects o1, o2: if o1 == o2 then hash(o1) ==
+ *       hash(o2)}
+ *   <li>Whenever two hash codes are different, their associated objects are different: {@code For all objects
+ *       o1, o2: if hash(o1) != hash(o2) then o1 != o2.
+ * </ul>
+ */
+@GenerateUncached
+public abstract class HashCodeAnyNode extends Node {
+
+  public static HashCodeAnyNode build() {
+    return HashCodeAnyNodeGen.create();
+  }
+
+  public abstract long execute(@AcceptsError Object self);
+
+  /** Specializations for primitive values * */
+  @Specialization
+  long hashCodeForShort(short s) {
+    return s;
+  }
+
+  @Specialization
+  long hashCodeForByte(byte b) {
+    return b;
+  }
+
+  @Specialization
+  long hashCodeForLong(long l) {
+    return Long.hashCode(l);
+  }
+
+  @Specialization
+  long hashCodeForInt(int i) {
+    return i;
+  }
+
+  @Specialization
+  long hashCodeForFloat(float f) {
+    return Float.hashCode(f);
+  }
+
+  @Specialization
+  @TruffleBoundary
+  long hashCodeForDouble(double d) {
+    if (d % 1.0 != 0.0) {
+      return Double.hashCode(d);
+    } else {
+      if (BigIntegerOps.fitsInLong(d)) {
+        return hashCodeForLong(Double.valueOf(d).longValue());
+      } else {
+        try {
+          return BigDecimal.valueOf(d).toBigIntegerExact().hashCode();
+        } catch (ArithmeticException e) {
+          throw new IllegalStateException(e);
+        }
+      }
+    }
+  }
+
+  @Specialization
+  @TruffleBoundary
+  long hashCodeForBigInteger(EnsoBigInteger bigInteger) {
+    return bigInteger.getValue().hashCode();
+  }
+
+  @Specialization
+  long hashCodeForAtomConstructor(AtomConstructor atomConstructor) {
+    return System.identityHashCode(atomConstructor);
+  }
+
+  /** How many {@link HashCodeAnyNode} nodes should be created for fields in atoms. */
+  static final int hashCodeNodeCountForFields = 10;
+
+  static HashCodeAnyNode[] createHashCodeNodes(int size) {
+    HashCodeAnyNode[] nodes = new HashCodeAnyNode[size];
+    Arrays.fill(nodes, HashCodeAnyNode.build());
+    return nodes;
+  }
+
+  @Specialization
+  long hashCodeForAtom(
+      Atom atom,
+      @Cached(value = "createHashCodeNodes(hashCodeNodeCountForFields)", allowUncached = true)
+          HashCodeAnyNode[] fieldHashCodeNodes,
+      @Cached ConditionProfile isHashCodeCached,
+      @Cached ConditionProfile enoughHashCodeNodesForFields,
+      @Cached LoopConditionProfile loopProfile) {
+    if (isHashCodeCached.profile(atom.getHashCode() != null)) {
+      return atom.getHashCode();
+    }
+    // TODO[PM]: If atom overrides hash_code, call that method (Will be done in a follow-up PR for
+    // https://www.pivotaltracker.com/story/show/183945328)
+    int fieldsCount = atom.getFields().length;
+    Object[] fields = atom.getFields();
+    // hashes stores hash codes for all fields, and for constructor.
+    int[] hashes = new int[fieldsCount + 1];
+    if (enoughHashCodeNodesForFields.profile(fieldsCount <= hashCodeNodeCountForFields)) {
+      loopProfile.profileCounted(fieldsCount);
+      for (int i = 0; loopProfile.inject(i < fieldsCount); i++) {
+        hashes[i] = (int) fieldHashCodeNodes[i].execute(fields[i]);
+      }
+    } else {
+      hashCodeForAtomFieldsUncached(fields, hashes);
+    }
+
+    int ctorHashCode = System.identityHashCode(atom.getConstructor());
+    hashes[hashes.length - 1] = ctorHashCode;
+
+    int atomHashCode = Arrays.hashCode(hashes);
+    atom.setHashCode(atomHashCode);
+    return atomHashCode;
+  }
+
+  @TruffleBoundary
+  private void hashCodeForAtomFieldsUncached(Object[] fields, int[] fieldHashes) {
+    for (int i = 0; i < fields.length; i++) {
+      fieldHashes[i] = (int) HashCodeAnyNodeGen.getUncached().execute(fields[i]);
+    }
+  }
+
+  @Specialization(
+      guards = {"warnLib.hasWarnings(selfWithWarning)"},
+      limit = "3")
+  long hashCodeForWarning(
+      Object selfWithWarning,
+      @CachedLibrary("selfWithWarning") WarningsLibrary warnLib,
+      @Cached HashCodeAnyNode hashCodeNode) {
+    try {
+      return hashCodeNode.execute(warnLib.removeWarnings(selfWithWarning));
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  /** Specializations for interop values * */
+  @Specialization(
+      guards = {"interop.isBoolean(selfBool)"},
+      limit = "3")
+  long hashCodeForBooleanInterop(
+      Object selfBool, @CachedLibrary("selfBool") InteropLibrary interop) {
+    try {
+      return Boolean.hashCode(interop.asBoolean(selfBool));
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @TruffleBoundary
+  @Specialization(
+      guards = {
+        "!interop.isDate(selfTimeZone)",
+        "!interop.isTime(selfTimeZone)",
+        "interop.isTimeZone(selfTimeZone)",
+      },
+      limit = "3")
+  long hashCodeForTimeZoneInterop(
+      Object selfTimeZone, @CachedLibrary("selfTimeZone") InteropLibrary interop) {
+    try {
+      return interop.asTimeZone(selfTimeZone).hashCode();
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @TruffleBoundary
+  @Specialization(
+      guards = {
+        "interop.isDate(selfZonedDateTime)",
+        "interop.isTime(selfZonedDateTime)",
+        "interop.isTimeZone(selfZonedDateTime)",
+      },
+      limit = "3")
+  long hashCodeForZonedDateTimeInterop(
+      Object selfZonedDateTime, @CachedLibrary("selfZonedDateTime") InteropLibrary interop) {
+    try {
+      return ZonedDateTime.of(
+              interop.asDate(selfZonedDateTime),
+              interop.asTime(selfZonedDateTime),
+              interop.asTimeZone(selfZonedDateTime))
+          .hashCode();
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Specialization(
+      guards = {
+        "interop.isDate(selfDateTime)",
+        "interop.isTime(selfDateTime)",
+        "!interop.isTimeZone(selfDateTime)",
+      },
+      limit = "3")
+  long hashCodeForDateTimeInterop(
+      Object selfDateTime, @CachedLibrary("selfDateTime") InteropLibrary interop) {
+    try {
+      return LocalDateTime.of(interop.asDate(selfDateTime), interop.asTime(selfDateTime))
+          .hashCode();
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Specialization(
+      guards = {
+        "!interop.isDate(selfTime)",
+        "interop.isTime(selfTime)",
+        "!interop.isTimeZone(selfTime)",
+      },
+      limit = "3")
+  long hashCodeForTimeInterop(Object selfTime, @CachedLibrary("selfTime") InteropLibrary interop) {
+    try {
+      return interop.asTime(selfTime).hashCode();
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Specialization(
+      guards = {
+        "interop.isDate(selfDate)",
+        "!interop.isTime(selfDate)",
+        "!interop.isTimeZone(selfDate)",
+      },
+      limit = "3")
+  long hashCodeForDateInterop(Object selfDate, @CachedLibrary("selfDate") InteropLibrary interop) {
+    try {
+      return interop.asDate(selfDate).hashCode();
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Specialization(
+      guards = {
+        "interop.isDuration(selfDuration)",
+      },
+      limit = "3")
+  long hashCodeForDurationInterop(
+      Object selfDuration, @CachedLibrary("selfDuration") InteropLibrary interop) {
+    try {
+      return interop.asDuration(selfDuration).hashCode();
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Specialization
+  long hashCodeForText(Text text, @CachedLibrary(limit = "3") InteropLibrary interop) {
+    if (text.is_normalized()) {
+      return text.toString().hashCode();
+    } else {
+      return hashCodeForString(text, interop);
+    }
+  }
+
+  @TruffleBoundary
+  @Specialization(
+      guards = {"interop.isString(selfStr)"},
+      limit = "3")
+  long hashCodeForString(Object selfStr, @CachedLibrary("selfStr") InteropLibrary interop) {
+    String str;
+    try {
+      str = interop.asString(selfStr);
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+    Normalizer2 normalizer = Normalizer2.getNFDInstance();
+    if (normalizer.isNormalized(str)) {
+      return str.hashCode();
+    } else {
+      return normalizer.normalize(str).hashCode();
+    }
+  }
+
+  @Specialization(
+      guards = {"interop.hasArrayElements(selfArray)"},
+      limit = "3")
+  long hashCodeForArray(
+      Object selfArray,
+      @CachedLibrary("selfArray") InteropLibrary interop,
+      @Cached HashCodeAnyNode hashCodeNode,
+      @Cached("createCountingProfile()") LoopConditionProfile loopProfile) {
+    try {
+      long arraySize = interop.getArraySize(selfArray);
+      loopProfile.profileCounted(arraySize);
+      int[] elemHashCodes = new int[(int) arraySize];
+      for (int i = 0; loopProfile.inject(i < arraySize); i++) {
+        if (interop.isArrayElementReadable(selfArray, i)) {
+          elemHashCodes[i] = (int) hashCodeNode.execute(interop.readArrayElement(selfArray, i));
+        }
+      }
+      return Arrays.hashCode(elemHashCodes);
+    } catch (UnsupportedMessageException | InvalidArrayIndexException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  /**
+   * Two maps are considered equal, if they have the same entries. Note that we do not care about
+   * ordering.
+   */
+  @Specialization(guards = "interop.hasHashEntries(selfMap)")
+  long hashCodeForMap(
+      Object selfMap,
+      @CachedLibrary(limit = "5") InteropLibrary interop,
+      @Cached HashCodeAnyNode hashCodeNode) {
+    int mapSize;
+    long keysHashCode = 0;
+    long valuesHashCode = 0;
+    try {
+      mapSize = (int) interop.getHashSize(selfMap);
+      Object entriesIterator = interop.getHashEntriesIterator(selfMap);
+      while (interop.hasIteratorNextElement(entriesIterator)) {
+        Object entry = interop.getIteratorNextElement(entriesIterator);
+        Object key = interop.readArrayElement(entry, 0);
+        Object value = interop.readArrayElement(entry, 1);
+        // We don't care about the order of keys and values, so we just sum all their hash codes.
+        keysHashCode += hashCodeNode.execute(key);
+        valuesHashCode += hashCodeNode.execute(value);
+      }
+    } catch (UnsupportedMessageException | StopIterationException | InvalidArrayIndexException e) {
+      throw new IllegalStateException(e);
+    }
+    return Arrays.hashCode(new long[] {keysHashCode, valuesHashCode, mapSize});
+  }
+
+  @Specialization(
+      guards = {"interop.isNull(selfNull)"},
+      limit = "3")
+  long hashCodeForNull(Object selfNull, @CachedLibrary("selfNull") InteropLibrary interop) {
+    return 0;
+  }
+
+  @Specialization(guards = "isHostObject(hostObject)")
+  long hashCodeForHostObject(
+      Object hostObject, @CachedLibrary(limit = "3") InteropLibrary interop) {
+    try {
+      Object hashCodeRes = interop.invokeMember(hostObject, "hashCode");
+      assert interop.fitsInInt(hashCodeRes);
+      return interop.asInt(hashCodeRes);
+    } catch (UnsupportedMessageException
+        | ArityException
+        | UnknownIdentifierException
+        | UnsupportedTypeException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @TruffleBoundary
+  boolean isHostObject(Object object) {
+    return EnsoContext.get(this).getEnvironment().isHostObject(object);
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/number/smallInteger/AbsNode.java

@@ -6,7 +6,7 @@ import org.enso.interpreter.dsl.BuiltinMethod;
 import org.enso.interpreter.node.expression.builtin.number.utils.BigIntegerOps;
 import org.enso.interpreter.node.expression.builtin.number.utils.ToEnsoNumberNode;
 
-@BuiltinMethod(type = "Small_Integer", name = "abs", description = "Negation for numbers.")
+@BuiltinMethod(type = "Small_Integer", name = "abs", description = "Absolute value of a number")
 public abstract class AbsNode extends Node {
   private @Child ToEnsoNumberNode toEnsoNumberNode = ToEnsoNumberNode.build();
 

engine/runtime/src/main/java/org/enso/interpreter/runtime/builtin/Builtins.java

@@ -92,6 +92,7 @@ public class Builtins {
   private final Builtin text;
   private final Builtin array;
   private final Builtin vector;
+  private final Builtin map;
   private final Builtin dataflowError;
   private final Builtin ref;
   private final Builtin managedResource;
@@ -137,6 +138,7 @@ public class Builtins {
     text = builtins.get(Text.class);
     array = builtins.get(Array.class);
     vector = builtins.get(Vector.class);
+    map = builtins.get(org.enso.interpreter.node.expression.builtin.Map.class);
     dataflowError = builtins.get(org.enso.interpreter.node.expression.builtin.Error.class);
     ref = builtins.get(Ref.class);
     managedResource = builtins.get(ManagedResource.class);
@@ -552,6 +554,10 @@ public class Builtins {
     return vector.getType();
   }
 
+  public Type map() {
+    return map.getType();
+  }
+
   /** @return the Ref constructor. */
   public Type ref() {
     return ref.getType();

engine/runtime/src/main/java/org/enso/interpreter/runtime/callable/atom/Atom.java

@@ -1,7 +1,15 @@
 package org.enso.interpreter.runtime.callable.atom;
 
 
+import com.oracle.truffle.api.Assumption;
 import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.Truffle;
+import com.oracle.truffle.api.dsl.Cached.Shared;
+import com.oracle.truffle.api.dsl.Fallback;
+import com.oracle.truffle.api.profiles.ConditionProfile;
+import com.oracle.truffle.api.profiles.ValueProfile;
+import com.oracle.truffle.api.utilities.TriState;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.exception.AbstractTruffleException;
@@ -12,11 +20,16 @@ import com.oracle.truffle.api.library.ExportMessage;
 import com.oracle.truffle.api.nodes.ExplodeLoop;
 import com.oracle.truffle.api.nodes.UnexpectedResultException;
 import com.oracle.truffle.api.profiles.BranchProfile;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
 import org.enso.interpreter.runtime.callable.UnresolvedSymbol;
 import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.data.Array;
 import org.enso.interpreter.runtime.data.Type;
 import org.enso.interpreter.runtime.data.text.Text;
+import org.enso.interpreter.runtime.error.PanicException;
 import org.enso.interpreter.runtime.library.dispatch.TypesLibrary;
 import org.enso.interpreter.runtime.type.TypesGen;
 
@@ -30,6 +43,7 @@ import org.enso.interpreter.runtime.error.WarningsLibrary;
 public final class Atom implements TruffleObject {
   final AtomConstructor constructor;
   private final Object[] fields;
+  private Integer hashCode;
 
   /**
    * Creates a new Atom for a given constructor.
@@ -60,6 +74,15 @@ public final class Atom implements TruffleObject {
     return fields;
   }
 
+  public void setHashCode(int hashCode) {
+    assert this.hashCode == null : "setHashCode must be called at most once";
+    this.hashCode = hashCode;
+  }
+
+  public Integer getHashCode() {
+    return hashCode;
+  }
+
   private void toString(StringBuilder builder, boolean shouldParen, int depth) {
     if (depth <= 0) {
       builder.append("...");

engine/runtime/src/main/java/org/enso/interpreter/runtime/callable/atom/AtomConstructor.java

@@ -10,6 +10,7 @@ import com.oracle.truffle.api.library.CachedLibrary;
 import com.oracle.truffle.api.library.ExportLibrary;
 import com.oracle.truffle.api.library.ExportMessage;
 import com.oracle.truffle.api.nodes.RootNode;
+import com.oracle.truffle.api.utilities.TriState;
 import org.enso.interpreter.node.ClosureRootNode;
 import org.enso.interpreter.node.ExpressionNode;
 import org.enso.interpreter.node.callable.argument.ReadArgumentNode;

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/EnsoHashMap.java

@@ -0,0 +1,194 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.TruffleObject;
+import com.oracle.truffle.api.interop.UnknownKeyException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.library.ExportLibrary;
+import com.oracle.truffle.api.library.ExportMessage;
+import com.oracle.truffle.api.profiles.ConditionProfile;
+import org.enso.interpreter.dsl.Builtin;
+import org.enso.interpreter.node.expression.builtin.meta.EqualsAnyNode;
+import org.enso.interpreter.node.expression.builtin.meta.HashCodeAnyNode;
+import org.enso.interpreter.runtime.EnsoContext;
+import org.enso.interpreter.runtime.data.Type;
+import org.enso.interpreter.runtime.data.Vector;
+import org.enso.interpreter.runtime.data.hash.EnsoHashMapBuilder.StorageEntry;
+import org.enso.interpreter.runtime.library.dispatch.TypesLibrary;
+
+/**
+ * Implementation of a hash map structure, capable of holding any types of keys and values. The
+ * actual hash map storage is implemented in {@link EnsoHashMapBuilder}, and every {@link
+ * EnsoHashMap} has just a reference to the builder and its size, which allows us to implement
+ * {@code insert} operation in constant time. In other words, every map is just a snapshot of its
+ * builder.
+ *
+ * <p>Users should not use Enso objects as keys to Java maps, because equals won't work the same way
+ * as it works in Enso.
+ */
+@ExportLibrary(TypesLibrary.class)
+@ExportLibrary(InteropLibrary.class)
+@Builtin(stdlibName = "Standard.Base.Data.Map.Map", name = "Map")
+public final class EnsoHashMap implements TruffleObject {
+  private final EnsoHashMapBuilder mapBuilder;
+  /**
+   * Size of this Map. Basically an index into {@link EnsoHashMapBuilder}'s storage. See {@link
+   * #isEntryInThisMap(StorageEntry)}.
+   */
+  private final int snapshotSize;
+  /**
+   * True iff {@code insert} method was already called. If insert was already called, and we are
+   * calling {@code insert} again, the {@link #mapBuilder} should be duplicated for the newly
+   * created Map.
+   */
+  private boolean insertCalled;
+
+  private Object cachedVectorRepresentation;
+
+  private EnsoHashMap(EnsoHashMapBuilder mapBuilder, int snapshotSize) {
+    this.mapBuilder = mapBuilder;
+    this.snapshotSize = snapshotSize;
+    assert snapshotSize <= mapBuilder.getSize();
+  }
+
+  static EnsoHashMap createWithBuilder(EnsoHashMapBuilder mapBuilder, int snapshotSize) {
+    return new EnsoHashMap(mapBuilder, snapshotSize);
+  }
+
+  static EnsoHashMap createEmpty(HashCodeAnyNode hashCodeAnyNode, EqualsAnyNode equalsNode) {
+    return new EnsoHashMap(EnsoHashMapBuilder.create(hashCodeAnyNode, equalsNode), 0);
+  }
+
+  EnsoHashMapBuilder getMapBuilder() {
+    return mapBuilder;
+  }
+
+  Object getCachedVectorRepresentation() {
+    return getCachedVectorRepresentation(ConditionProfile.getUncached());
+  }
+
+  Object getCachedVectorRepresentation(ConditionProfile isNotCachedProfile) {
+    if (isNotCachedProfile.profile(cachedVectorRepresentation == null)) {
+      Object[] keys = new Object[snapshotSize];
+      Object[] values = new Object[snapshotSize];
+      int arrIdx = 0;
+      for (StorageEntry entry : mapBuilder.getStorage().getValues()) {
+        if (entry.index() < snapshotSize) {
+          keys[arrIdx] = entry.key();
+          values[arrIdx] = entry.value();
+          arrIdx++;
+        }
+      }
+      cachedVectorRepresentation =
+          Vector.fromArray(HashEntriesVector.createFromKeysAndValues(keys, values));
+    }
+    return cachedVectorRepresentation;
+  }
+
+  public boolean isInsertCalled() {
+    return insertCalled;
+  }
+
+  public void setInsertCalled() {
+    assert !insertCalled : "setInsertCalled should be called at most once";
+    insertCalled = true;
+  }
+
+  @Builtin.Method
+  @Builtin.Specialize
+  public static EnsoHashMap empty(
+      @Cached HashCodeAnyNode hashCodeNode, @Cached EqualsAnyNode equalsNode) {
+    return createEmpty(hashCodeNode, equalsNode);
+  }
+
+  @ExportMessage
+  boolean hasHashEntries() {
+    return true;
+  }
+
+  @ExportMessage
+  int getHashSize() {
+    return snapshotSize;
+  }
+
+  @ExportMessage
+  boolean isHashEntryExisting(Object key) {
+    return isEntryInThisMap(mapBuilder.get(key));
+  }
+
+  @ExportMessage
+  boolean isHashEntryReadable(Object key) {
+    return isHashEntryExisting(key);
+  }
+
+  @ExportMessage
+  Object readHashValue(Object key) throws UnknownKeyException {
+    StorageEntry entry = mapBuilder.get(key);
+    if (isEntryInThisMap(entry)) {
+      return entry.value();
+    } else {
+      throw UnknownKeyException.create(key);
+    }
+  }
+
+  @ExportMessage
+  Object getHashEntriesIterator(@CachedLibrary(limit = "3") InteropLibrary interop) {
+    try {
+      return interop.getIterator(getCachedVectorRepresentation());
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @ExportMessage(library = TypesLibrary.class)
+  boolean hasType() {
+    return true;
+  }
+
+  @ExportMessage(library = TypesLibrary.class)
+  Type getType(@CachedLibrary("this") TypesLibrary thisLib) {
+    return EnsoContext.get(thisLib).getBuiltins().map();
+  }
+
+  @ExportMessage
+  boolean hasMetaObject() {
+    return true;
+  }
+
+  @ExportMessage
+  Type getMetaObject(@CachedLibrary("this") InteropLibrary thisLib) {
+    return EnsoContext.get(thisLib).getBuiltins().map();
+  }
+
+  @ExportMessage
+  @TruffleBoundary
+  Object toDisplayString(boolean allowSideEffects) {
+    var sb = new StringBuilder();
+    sb.append("{");
+    boolean empty = true;
+    for (StorageEntry entry : mapBuilder.getStorage().getValues()) {
+      if (isEntryInThisMap(entry)) {
+        empty = false;
+        sb.append(entry.key()).append("=").append(entry.value()).append(", ");
+      }
+    }
+    if (!empty) {
+      // Delete last comma
+      sb.delete(sb.length() - 2, sb.length());
+    }
+    sb.append("}");
+    return sb.toString();
+  }
+
+  @Override
+  public String toString() {
+    return (String) toDisplayString(true);
+  }
+
+  private boolean isEntryInThisMap(StorageEntry entry) {
+    return entry != null && entry.index() < snapshotSize;
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/EnsoHashMapBuilder.java

@@ -0,0 +1,188 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import java.util.ArrayList;
+import java.util.List;
+import org.enso.interpreter.node.expression.builtin.meta.EqualsAnyNode;
+import org.enso.interpreter.node.expression.builtin.meta.HashCodeAnyNode;
+import org.graalvm.collections.EconomicMap;
+import org.graalvm.collections.Equivalence;
+
+/**
+ * A storage for a {@link EnsoHashMap}. For one builder, there may be many snapshots ({@link
+ * EnsoHashMap}). There should be at most one snapshot for a given size. All the snapshots should
+ * have size smaller than this builder size.
+ */
+public final class EnsoHashMapBuilder {
+  private final EconomicMap<Object, StorageEntry> storage;
+  /** All entries stored by their sequential index. */
+  private final List<StorageEntry> sequentialEntries;
+
+  private final HashCodeAnyNode hashCodeNode;
+  private final EqualsAnyNode equalsNode;
+  private int size;
+
+  private EnsoHashMapBuilder(HashCodeAnyNode hashCodeAnyNode, EqualsAnyNode equalsNode) {
+    this.storage = EconomicMap.create(new StorageStrategy(equalsNode, hashCodeAnyNode));
+    this.sequentialEntries = new ArrayList<>();
+    this.hashCodeNode = hashCodeAnyNode;
+    this.equalsNode = equalsNode;
+  }
+
+  private EnsoHashMapBuilder(EnsoHashMapBuilder other, int numEntries) {
+    assert 0 < numEntries && numEntries <= other.size;
+    this.storage = EconomicMap.create(new StorageStrategy(other.equalsNode, other.hashCodeNode));
+    var entriesToBeDuplicated = other.sequentialEntries.subList(0, numEntries);
+    this.sequentialEntries = new ArrayList<>(entriesToBeDuplicated);
+    entriesToBeDuplicated.forEach(entry -> this.storage.put(entry.key, entry));
+    this.hashCodeNode = other.hashCodeNode;
+    this.equalsNode = other.equalsNode;
+    this.size = numEntries;
+  }
+
+  private EnsoHashMapBuilder(EnsoHashMapBuilder other) {
+    this.storage =
+        EconomicMap.create(
+            new StorageStrategy(other.equalsNode, other.hashCodeNode), other.storage);
+    this.sequentialEntries = new ArrayList<>(other.sequentialEntries);
+    this.hashCodeNode = other.hashCodeNode;
+    this.equalsNode = other.equalsNode;
+    this.size = other.size;
+  }
+
+  /**
+   * Create a new builder with stored nodes.
+   *
+   * @param hashCodeNode Node that will be stored in the storage for invoking `hash_code` on keys.
+   * @param equalsNode Node that will be stored in the storage for invoking `==` on keys.
+   */
+  public static EnsoHashMapBuilder create(HashCodeAnyNode hashCodeNode, EqualsAnyNode equalsNode) {
+    return new EnsoHashMapBuilder(hashCodeNode, equalsNode);
+  }
+
+  /** Returns count of elements in the storage. */
+  public int getSize() {
+    return size;
+  }
+
+  public EconomicMap<Object, StorageEntry> getStorage() {
+    return storage;
+  }
+
+  /**
+   * Duplicates the MapBuilder with just first {@code numEntries} number of entries.
+   *
+   * @param numEntries Number of entries to take from this MapBuilder.
+   */
+  public EnsoHashMapBuilder duplicatePartial(int numEntries) {
+    return new EnsoHashMapBuilder(this, numEntries);
+  }
+
+  /** Duplicates this builder with all its entries. */
+  @TruffleBoundary
+  public EnsoHashMapBuilder duplicate() {
+    return new EnsoHashMapBuilder(this);
+  }
+
+  /** Adds a key-value mapping, overriding any existing value. */
+  @TruffleBoundary(allowInlining = true)
+  public void add(Object key, Object value) {
+    var oldEntry = storage.get(key);
+    int newEntryIndex = oldEntry != null ? oldEntry.index : size;
+    var newEntry = new StorageEntry(key, value, newEntryIndex);
+    storage.put(key, newEntry);
+    if (oldEntry == null) {
+      assert newEntry.index == size;
+      sequentialEntries.add(newEntry);
+      size++;
+    } else {
+      sequentialEntries.set(newEntryIndex, newEntry);
+    }
+  }
+
+  @TruffleBoundary(allowInlining = true)
+  public StorageEntry get(Object key) {
+    return storage.get(key);
+  }
+
+  /**
+   * Removes an entry denoted by the given key.
+   *
+   * @return true if the removal was successful, i.e., the key was in the map and was removed, false
+   *     otherwise.
+   */
+  @TruffleBoundary
+  public boolean remove(Object key) {
+    var oldEntry = storage.removeKey(key);
+    if (oldEntry == null) {
+      return false;
+    } else {
+      sequentialEntries.remove(oldEntry.index);
+      // Rewrite rest of the sequentialEntries list and repair indexes in storage
+      for (int i = oldEntry.index; i < sequentialEntries.size(); i++) {
+        var entry = sequentialEntries.get(i);
+        StorageEntry newEntry = new StorageEntry(entry.key, entry.value, i);
+        sequentialEntries.set(i, newEntry);
+        storage.put(newEntry.key, newEntry);
+      }
+      size--;
+      return true;
+    }
+  }
+
+  @TruffleBoundary(allowInlining = true)
+  public boolean containsKey(Object key) {
+    return storage.containsKey(key);
+  }
+
+  /**
+   * Creates a snapshot with the current size. The created snapshot contains all the entries that
+   * are in the storage as of this moment, i.e., all the entries with their indexes lesser than
+   * {@code size}.
+   *
+   * <p>Should be called at most once for a particular {@code size}.
+   *
+   * @return A new hash map snapshot.
+   */
+  public EnsoHashMap build() {
+    return EnsoHashMap.createWithBuilder(this, size);
+  }
+
+  @Override
+  public String toString() {
+    return "EnsoHashMapBuilder{size = " + size + ", storage = " + storage + "}";
+  }
+
+  record StorageEntry(
+      Object key,
+      Object value,
+      /**
+       * A sequential index of the entry within this map. {@link EnsoHashMap} uses it for checking
+       * whether a certain key belongs in that map.
+       */
+      int index) {}
+
+  /**
+   * Custom {@link Equivalence} used for the {@link EconomicMap} that delegates {@code equals} to
+   * {@link EqualsAnyNode} and {@code hash_code} to {@link HashCodeAnyNode}.
+   */
+  private static final class StorageStrategy extends Equivalence {
+    private final EqualsAnyNode equalsNode;
+    private final HashCodeAnyNode hashCodeNode;
+
+    private StorageStrategy(EqualsAnyNode equalsNode, HashCodeAnyNode hashCodeNode) {
+      this.equalsNode = equalsNode;
+      this.hashCodeNode = hashCodeNode;
+    }
+
+    @Override
+    public boolean equals(Object a, Object b) {
+      return equalsNode.execute(a, b);
+    }
+
+    @Override
+    public int hashCode(Object o) {
+      return (int) hashCodeNode.execute(o);
+    }
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashEntriesVector.java

@@ -0,0 +1,133 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.TruffleObject;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.ExportLibrary;
+import com.oracle.truffle.api.library.ExportMessage;
+import org.enso.interpreter.runtime.data.Vector;
+
+/**
+ * A vector used to hold hash map entries, where each entry is represented as a 2-element vector.
+ * Used for both Truffle interop, where {@code getHashEntriesIterator} expects this form of vector
+ * (array), and for Enso {@code Map.to_vector} method. May be empty.
+ */
+@ExportLibrary(InteropLibrary.class)
+final class HashEntriesVector implements TruffleObject {
+  private final Vector[] entryPairs;
+
+  private HashEntriesVector(Object[] keys, Object[] values) {
+    assert keys.length == values.length;
+    this.entryPairs = new Vector[keys.length];
+    for (int i = 0; i < keys.length; i++) {
+      entryPairs[i] = Vector.fromArray(new EntryPair(keys[i], values[i]));
+    }
+  }
+
+  static HashEntriesVector createFromKeysAndValues(Object[] keys, Object[] values) {
+    return new HashEntriesVector(keys, values);
+  }
+
+  static HashEntriesVector createEmpty() {
+    return new HashEntriesVector(new Object[] {}, new Object[] {});
+  }
+
+  @ExportMessage
+  boolean hasArrayElements() {
+    return true;
+  }
+
+  @ExportMessage
+  long getArraySize() {
+    return entryPairs.length;
+  }
+
+  @ExportMessage
+  boolean isArrayElementReadable(long idx) {
+    return idx < entryPairs.length;
+  }
+
+  @ExportMessage
+  boolean isArrayElementModifiable(long idx) {
+    return false;
+  }
+
+  @ExportMessage
+  boolean isArrayElementInsertable(long idx) {
+    return false;
+  }
+
+  @ExportMessage
+  Object readArrayElement(long idx) throws InvalidArrayIndexException {
+    if (idx < entryPairs.length) {
+      return entryPairs[(int) idx];
+    } else {
+      throw InvalidArrayIndexException.create(idx);
+    }
+  }
+
+  @ExportMessage
+  void writeArrayElement(long index, Object value) throws UnsupportedMessageException {
+    throw UnsupportedMessageException.create();
+  }
+
+  @ExportLibrary(InteropLibrary.class)
+  static final class EntryPair implements TruffleObject {
+    private final Object key;
+    private final Object value;
+
+    EntryPair(Object key, Object value) {
+      this.key = key;
+      this.value = value;
+    }
+
+    @ExportMessage
+    boolean hasArrayElements() {
+      return true;
+    }
+
+    @ExportMessage
+    long getArraySize() {
+      return 2;
+    }
+
+    @ExportMessage
+    boolean isArrayElementReadable(long idx) {
+      return idx < 2;
+    }
+
+    @ExportMessage
+    Object readArrayElement(long idx) throws InvalidArrayIndexException {
+      if (idx == 0) {
+        return key;
+      } else if (idx == 1) {
+        return value;
+      } else {
+        throw InvalidArrayIndexException.create(idx);
+      }
+    }
+
+    @ExportMessage
+    boolean isArrayElementModifiable(long idx) {
+      return false;
+    }
+
+    @ExportMessage
+    boolean isArrayElementInsertable(long idx) {
+      return false;
+    }
+
+    @ExportMessage
+    void writeArrayElement(long index, Object value) throws UnsupportedMessageException {
+      throw UnsupportedMessageException.create();
+    }
+
+    @TruffleBoundary
+    @ExportMessage
+    Object toDisplayString(boolean sideEffectsAllowed) {
+      return "(" + key + ", " + value + ")";
+    }
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashMapContainsKeyNode.java

@@ -0,0 +1,40 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.dsl.Fallback;
+import com.oracle.truffle.api.dsl.GenerateUncached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.BuiltinMethod;
+
+@BuiltinMethod(
+    type = "Map",
+    name = "contains_key",
+    description = """
+        Returns True if the hash map contains mapping with the given key, False otherwise.
+        """,
+    autoRegister = false
+)
+@GenerateUncached
+public abstract class HashMapContainsKeyNode extends Node {
+
+  public static HashMapContainsKeyNode build() {
+    return HashMapContainsKeyNodeGen.create();
+  }
+
+  public abstract boolean execute(Object self, Object key);
+
+  @Specialization(guards = {
+      "interop.hasHashEntries(foreignMap)"
+  }, limit = "3")
+  boolean doForeignHashMap(Object foreignMap, Object key,
+      @CachedLibrary("foreignMap") InteropLibrary interop) {
+    return interop.isHashEntryExisting(foreignMap, key);
+  }
+
+  @Fallback
+  boolean fallback(Object map, Object key) {
+    return false;
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashMapGetNode.java

@@ -0,0 +1,55 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.Fallback;
+import com.oracle.truffle.api.dsl.GenerateUncached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.UnknownKeyException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.dsl.Suspend;
+import org.enso.interpreter.node.BaseNode.TailStatus;
+import org.enso.interpreter.node.callable.thunk.ThunkExecutorNode;
+import org.enso.interpreter.runtime.state.State;
+
+@BuiltinMethod(
+    type = "Map",
+    name = "get_builtin",
+    description = """
+        Gets a value from the map on the specified key, or the given default.
+        """,
+    autoRegister = false
+)
+@GenerateUncached
+public abstract class HashMapGetNode extends Node {
+
+  public static HashMapGetNode build() {
+    return HashMapGetNodeGen.create();
+  }
+
+  public abstract Object execute(State state, Object self, Object key, @Suspend Object defaultValue);
+
+  @Specialization(guards = "interop.hasHashEntries(self)", limit = "3")
+  Object hashMapGet(State state, Object self, Object key, Object defaultValue,
+      @CachedLibrary("self") InteropLibrary interop,
+      @Cached("build()") ThunkExecutorNode thunkExecutorNode) {
+    if (interop.isHashEntryReadable(self, key)) {
+      try {
+        return interop.readHashValue(self, key);
+      } catch (UnsupportedMessageException | UnknownKeyException e) {
+        throw new IllegalStateException(e);
+      }
+    } else {
+      return thunkExecutorNode.executeThunk(defaultValue, state, TailStatus.NOT_TAIL);
+    }
+  }
+
+  @Fallback
+  Object fallback(State state, Object self, Object key, Object defaultValue,
+      @Cached("build()") ThunkExecutorNode thunkExecutorNode) {
+    return thunkExecutorNode.executeThunk(defaultValue, state, TailStatus.NOT_TAIL);
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashMapInsertNode.java

@@ -0,0 +1,84 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.StopIterationException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.node.expression.builtin.meta.EqualsAnyNode;
+import org.enso.interpreter.node.expression.builtin.meta.HashCodeAnyNode;
+
+@BuiltinMethod(
+    type = "Map",
+    name = "insert",
+    description = """
+        Returns newly created hash map with the given key value mapping.
+        """,
+    autoRegister = false
+)
+public abstract class HashMapInsertNode extends Node {
+
+  public static HashMapInsertNode build() {
+    return HashMapInsertNodeGen.create();
+  }
+
+  public abstract EnsoHashMap execute(Object self, Object key, Object value);
+
+  @Specialization
+  @TruffleBoundary
+  EnsoHashMap doEnsoHashMap(EnsoHashMap hashMap, Object key, Object value) {
+    EnsoHashMapBuilder mapBuilder = hashMap.getMapBuilder();
+    boolean containsKey = mapBuilder.get(key) != null;
+    boolean insertCalledOnMap = hashMap.isInsertCalled();
+    if (insertCalledOnMap || containsKey) {
+      // insert was already called on this map => We need to duplicate MapBuilder
+      // If a key is already contained in the Map there is no way telling whether there is another
+      // binding pointing to the Map, and we do not want to mutate this older binding.
+      var newMapBuilder = hashMap.getHashSize() < mapBuilder.getSize() ?
+          mapBuilder.duplicatePartial(hashMap.getHashSize()) :
+          mapBuilder.duplicate();
+      newMapBuilder.add(key, value);
+      return newMapBuilder.build();
+    } else {
+      // Do not duplicate the builder, just create a snapshot.
+      mapBuilder.add(key, value);
+      var newMap = mapBuilder.build();
+      hashMap.setInsertCalled();
+      return newMap;
+    }
+  }
+
+  /**
+   * Creates a new {@link EnsoHashMapBuilder} for the given {@code foreignMap} - iterates through
+   * all the entries of the foreign map. The returned map is {@link EnsoHashMap}.
+   */
+  @Specialization(guards = "mapInterop.hasHashEntries(foreignMap)", limit = "3")
+  EnsoHashMap doForeign(Object foreignMap, Object keyToInsert, Object valueToInsert,
+      @CachedLibrary("foreignMap") InteropLibrary mapInterop,
+      @CachedLibrary(limit = "3") InteropLibrary iteratorInterop,
+      @Cached HashCodeAnyNode hashCodeNode,
+      @Cached EqualsAnyNode equalsNode) {
+    var mapBuilder = EnsoHashMapBuilder.create(hashCodeNode, equalsNode);
+    try {
+      Object entriesIterator = mapInterop.getHashEntriesIterator(foreignMap);
+      while (iteratorInterop.hasIteratorNextElement(entriesIterator)) {
+        Object keyValueArr = iteratorInterop.getIteratorNextElement(entriesIterator);
+        Object key = iteratorInterop.readArrayElement(keyValueArr, 0);
+        Object value = iteratorInterop.readArrayElement(keyValueArr, 1);
+        mapBuilder.add(key, value);
+      }
+    } catch (UnsupportedMessageException | StopIterationException | InvalidArrayIndexException e) {
+      throw new IllegalStateException(
+          "Polyglot hash map " + foreignMap + " has wrongly specified Interop API (hash entries iterator)",
+          e
+      );
+    }
+    mapBuilder.add(keyToInsert, valueToInsert);
+    return EnsoHashMap.createWithBuilder(mapBuilder, mapBuilder.getSize());
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashMapRemoveNode.java

@@ -0,0 +1,88 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.GenerateUncached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.StopIterationException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.node.expression.builtin.meta.EqualsAnyNode;
+import org.enso.interpreter.node.expression.builtin.meta.HashCodeAnyNode;
+import org.enso.interpreter.runtime.error.DataflowError;
+
+@BuiltinMethod(
+    type = "Map",
+    name = "remove_builtin",
+    description = """
+        Removes an entry from this map specified with the key.
+        """
+)
+@GenerateUncached
+public abstract class HashMapRemoveNode extends Node {
+  public static HashMapRemoveNode build() {
+    return HashMapRemoveNodeGen.create();
+  }
+
+  public abstract EnsoHashMap execute(Object self, Object key);
+
+  @Specialization
+  EnsoHashMap removeFromEnsoMap(EnsoHashMap ensoMap, Object key) {
+    var oldEntry = ensoMap.getMapBuilder().get(key);
+    if (oldEntry == null) {
+      throw DataflowError.withoutTrace("No such key", null);
+    } else {
+      var newBuilder = ensoMap.getMapBuilder().duplicate();
+      if (!newBuilder.remove(key)) {
+        throw new IllegalStateException("Key '" + key + "' should be in the map");
+      }
+      return EnsoHashMap.createWithBuilder(newBuilder, newBuilder.getSize());
+    }
+  }
+
+  @Specialization(
+      guards = "interop.hasHashEntries(map)"
+  )
+  EnsoHashMap removeFromInteropMap(Object map, Object keyToRemove,
+      @CachedLibrary(limit = "5") InteropLibrary interop,
+      @Cached HashCodeAnyNode hashCodeNode,
+      @Cached EqualsAnyNode equalsNode) {
+    // We cannot simply call interop.isHashEntryExisting, because it would, most likely
+    // use the default `hashCode` and `equals` Java methods. But we need to use our
+    // EqualsAnyNode, so we do the check for non-existing key inside the while loop.
+    boolean keyToRemoveFound = false;
+    var mapBuilder = EnsoHashMapBuilder.create(hashCodeNode, equalsNode);
+    try {
+      Object entriesIterator = interop.getHashEntriesIterator(map);
+      while (interop.hasIteratorNextElement(entriesIterator)) {
+        Object keyValueArr = interop.getIteratorNextElement(entriesIterator);
+        Object key = interop.readArrayElement(keyValueArr, 0);
+        if (equalsNode.execute(keyToRemove, key)) {
+          if (keyToRemoveFound) {
+            throw new IllegalStateException("Key " + key + " found twice");
+          } else {
+            keyToRemoveFound = true;
+          }
+        } else {
+          Object value = interop.readArrayElement(keyValueArr, 1);
+          mapBuilder.add(key, value);
+        }
+      }
+    } catch (UnsupportedMessageException | StopIterationException | InvalidArrayIndexException e) {
+      throw new IllegalStateException(
+          "Polyglot hash map " + map + " has wrongly specified Interop API (hash entries iterator)",
+          e
+      );
+    }
+    if (keyToRemoveFound) {
+      return EnsoHashMap.createWithBuilder(mapBuilder, mapBuilder.getSize());
+    } else {
+      CompilerDirectives.transferToInterpreter();
+      throw DataflowError.withoutTrace("No such key " + keyToRemove, interop);
+    }
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashMapSizeNode.java

@@ -0,0 +1,39 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.dsl.Fallback;
+import com.oracle.truffle.api.dsl.GenerateUncached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.BuiltinMethod;
+
+@BuiltinMethod(
+    type = "Map",
+    name = "size",
+    description = "Returns the number of entries in this hash map",
+    autoRegister = false)
+@GenerateUncached
+public abstract class HashMapSizeNode extends Node {
+
+  public static HashMapSizeNode build() {
+    return HashMapSizeNodeGen.create();
+  }
+
+  public abstract long execute(Object self);
+
+  @Specialization(guards = "interop.hasHashEntries(hashMap)", limit = "3")
+  long getHashMapSize(Object hashMap, @CachedLibrary("hashMap") InteropLibrary interop) {
+    try {
+      return interop.getHashSize(hashMap);
+    } catch (UnsupportedMessageException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Fallback
+  long fallback(Object hashMap) {
+    return 0;
+  }
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashMapToTextNode.java

@@ -0,0 +1,57 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.StopIterationException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.dsl.BuiltinMethod;
+
+@BuiltinMethod(
+    type = "Map",
+    name = "to_text",
+    description = """
+        Returns text representation of this hash map
+        """,
+    autoRegister = false
+)
+public abstract class HashMapToTextNode extends Node {
+
+  public static HashMapToTextNode build() {
+    return HashMapToTextNodeGen.create();
+  }
+
+  public abstract Object execute(Object self);
+
+  @TruffleBoundary
+  @Specialization(guards = "interop.hasHashEntries(hashMap)")
+  Object hashMapToText(Object hashMap,
+      @CachedLibrary(limit = "5") InteropLibrary interop) {
+    var sb = new StringBuilder();
+    sb.append("{");
+    try {
+      Object entryIterator = interop.getHashEntriesIterator(hashMap);
+      while (interop.hasIteratorNextElement(entryIterator)) {
+        Object keyValuePair = interop.getIteratorNextElement(entryIterator);
+        Object key = interop.readArrayElement(keyValuePair, 0);
+        Object value = interop.readArrayElement(keyValuePair, 1);
+        sb.append(key).append("=").append(value).append(", ");
+      }
+      if (interop.getHashSize(hashMap) > 0) {
+        // Delete last comma
+        sb.delete(sb.length() - 2, sb.length());
+      }
+    } catch (UnsupportedMessageException | StopIterationException | InvalidArrayIndexException e) {
+      throw new IllegalStateException(
+          "hashMap " + hashMap + " probably implements interop API incorrectly",
+          e
+      );
+    }
+    sb.append("}");
+    return sb.toString();
+  }
+}
+

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/hash/HashMapToVectorNode.java

@@ -0,0 +1,78 @@
+package org.enso.interpreter.runtime.data.hash;
+
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.Fallback;
+import com.oracle.truffle.api.dsl.GenerateUncached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.InvalidArrayIndexException;
+import com.oracle.truffle.api.interop.StopIterationException;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.nodes.Node;
+import com.oracle.truffle.api.profiles.ConditionProfile;
+import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.runtime.data.Vector;
+
+
+@BuiltinMethod(
+    type = "Map",
+    name = "to_vector",
+    description = """
+        Transforms the hash map into a vector of key value pairs. If possible, caches
+        the result. Key value pairs are represented as nested 2 element vectors.
+        """,
+    autoRegister = false
+)
+@GenerateUncached
+public abstract class HashMapToVectorNode extends Node {
+
+  public static HashMapToVectorNode build() {
+    return HashMapToVectorNodeGen.create();
+  }
+
+  public abstract Object execute(Object self);
+
+  @Specialization
+  Object ensoMapToVector(EnsoHashMap hashMap,
+      @Cached ConditionProfile vectorReprNotCachedProfile) {
+    return hashMap.getCachedVectorRepresentation(vectorReprNotCachedProfile);
+  }
+
+  @Specialization(guards = "mapInterop.hasHashEntries(hashMap)", limit = "3")
+  Object foreignMapToVector(Object hashMap,
+      @CachedLibrary("hashMap") InteropLibrary mapInterop,
+      @CachedLibrary(limit = "3") InteropLibrary iteratorInterop) {
+    return createEntriesVectorFromForeignMap(hashMap, mapInterop, iteratorInterop);
+  }
+
+  @Fallback
+  Object fallback(Object object) {
+    return Vector.fromArray(HashEntriesVector.createEmpty());
+  }
+
+  private static Object createEntriesVectorFromForeignMap(
+      Object hashMap,
+      InteropLibrary mapInterop,
+      InteropLibrary iteratorInterop) {
+    try {
+      int hashSize = (int) mapInterop.getHashSize(hashMap);
+      Object[] keys = new Object[hashSize];
+      Object[] values = new Object[hashSize];
+      Object entryIterator = mapInterop.getHashEntriesIterator(hashMap);
+      int arrIdx = 0;
+      while (iteratorInterop.hasIteratorNextElement(entryIterator)) {
+        Object keyValueArr = iteratorInterop.getIteratorNextElement(entryIterator);
+        keys[arrIdx] = iteratorInterop.readArrayElement(keyValueArr, 0);
+        values[arrIdx] = iteratorInterop.readArrayElement(keyValueArr, 1);
+        arrIdx++;
+      }
+      return Vector.fromArray(
+          HashEntriesVector.createFromKeysAndValues(keys, values)
+      );
+    } catch (UnsupportedMessageException | StopIterationException | InvalidArrayIndexException e) {
+      throw new IllegalStateException("hashMap: " + hashMap + " has probably wrong hash interop API", e);
+    }
+  }
+
+}

engine/runtime/src/main/java/org/enso/interpreter/runtime/data/text/Text.java

@@ -3,7 +3,9 @@ package org.enso.interpreter.runtime.data.text;
 import com.ibm.icu.text.BreakIterator;
 import com.ibm.icu.text.Normalizer2;
 import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.utilities.TriState;
 import com.oracle.truffle.api.interop.InteropLibrary;
 import com.oracle.truffle.api.interop.TruffleObject;
 import com.oracle.truffle.api.library.CachedLibrary;
@@ -83,7 +85,7 @@ public final class Text implements TruffleObject {
         return false;
       }
       case UNKNOWN -> {
-        Normalizer2 normalizer = Normalizer2.getInstance(null, "nfc", Normalizer2.Mode.FCD);
+        Normalizer2 normalizer = Normalizer2.getNFDInstance();
         boolean isNormalized = normalizer.isNormalized(toString());
         setFcdNormalized(isNormalized);
         return isNormalized;

engine/runtime/src/main/java/org/enso/interpreter/runtime/type/Types.java

@@ -9,6 +9,7 @@ import org.enso.interpreter.runtime.callable.atom.Atom;
 import org.enso.interpreter.runtime.callable.atom.AtomConstructor;
 import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.data.*;
+import org.enso.interpreter.runtime.data.hash.EnsoHashMap;
 import org.enso.interpreter.runtime.data.text.Text;
 import org.enso.interpreter.runtime.error.*;
 import org.enso.interpreter.runtime.number.EnsoBigInteger;
@@ -47,6 +48,7 @@ import org.enso.polyglot.data.TypeGraph;
   PanicException.class,
   PanicSentinel.class,
   Vector.class,
+  EnsoHashMap.class,
   Warning.class,
   EnsoFile.class,
   EnsoDate.class,

engine/runtime/src/test/java/org/enso/interpreter/test/EqualsTest.java

@@ -0,0 +1,101 @@
+package org.enso.interpreter.test;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+import org.enso.interpreter.node.expression.builtin.meta.EqualsAnyNode;
+import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.Value;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.experimental.theories.DataPoints;
+import org.junit.experimental.theories.Theories;
+import org.junit.experimental.theories.Theory;
+import org.junit.runner.RunWith;
+
+@RunWith(Theories.class)
+public class EqualsTest extends TestBase {
+  private static Context context;
+  private EqualsAnyNode equalsNode;
+
+  @BeforeClass
+  public static void initContextAndData() {
+    context = createDefaultContext();
+    unwrappedValues = fetchAllUnwrappedValues();
+  }
+
+  @Before
+  public void initNodes() {
+    executeInContext(
+        context,
+        () -> {
+          equalsNode = EqualsAnyNode.build();
+          return null;
+        });
+  }
+
+  @AfterClass
+  public static void disposeContext() {
+    context.close();
+  }
+
+  @DataPoints public static Object[] unwrappedValues;
+
+  private static Object[] fetchAllUnwrappedValues() {
+    var valGenerator =
+        ValuesGenerator.create(
+            context,
+            ValuesGenerator.Language.ENSO,
+            ValuesGenerator.Language.JAVA,
+            ValuesGenerator.Language.JAVASCRIPT,
+            ValuesGenerator.Language.PYTHON);
+    List<Value> values = new ArrayList<>();
+    values.addAll(valGenerator.numbers());
+    values.addAll(valGenerator.booleans());
+    values.addAll(valGenerator.textual());
+    values.addAll(valGenerator.arrayLike());
+    values.addAll(valGenerator.vectors());
+    values.addAll(valGenerator.maps());
+    values.addAll(valGenerator.multiLevelAtoms());
+    values.addAll(valGenerator.timesAndDates());
+    values.addAll(valGenerator.timeZones());
+    values.addAll(valGenerator.durations());
+    values.addAll(valGenerator.periods());
+    values.addAll(valGenerator.warnings());
+    try {
+      return values.stream()
+          .map(value -> unwrapValue(context, value))
+          .collect(Collectors.toList())
+          .toArray(new Object[] {});
+    } catch (Exception e) {
+      throw new AssertionError(e);
+    }
+  }
+
+  @Theory
+  public void equalsOperatorShouldBeSymmetric(Object firstValue, Object secondValue) {
+    executeInContext(
+        context,
+        () -> {
+          boolean firstResult = equalsNode.execute(firstValue, secondValue);
+          boolean secondResult = equalsNode.execute(firstValue, secondValue);
+          assertEquals("equals should be symmetric", firstResult, secondResult);
+          return null;
+        });
+  }
+
+  @Theory
+  public void equalsOperatorShouldBeConsistent(Object value) {
+    executeInContext(
+        context,
+        () -> {
+          boolean firstResult = equalsNode.execute(value, value);
+          boolean secondResult = equalsNode.execute(value, value);
+          assertEquals("equals should be consistent", firstResult, secondResult);
+          return null;
+        });
+  }
+}

engine/runtime/src/test/java/org/enso/interpreter/test/HashCodeTest.java

@@ -0,0 +1,136 @@
+package org.enso.interpreter.test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+
+import com.oracle.truffle.api.interop.InteropLibrary;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+import org.enso.interpreter.node.expression.builtin.meta.EqualsAnyNode;
+import org.enso.interpreter.node.expression.builtin.meta.HashCodeAnyNode;
+import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.Value;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.experimental.theories.DataPoints;
+import org.junit.experimental.theories.Theories;
+import org.junit.experimental.theories.Theory;
+import org.junit.runner.RunWith;
+
+@RunWith(Theories.class)
+public class HashCodeTest extends TestBase {
+  private static Context context;
+  private static final InteropLibrary interop = InteropLibrary.getUncached();
+
+  private HashCodeAnyNode hashCodeNode;
+  private EqualsAnyNode equalsNode;
+
+  @BeforeClass
+  public static void initContextAndData() {
+    context = createDefaultContext();
+    // Initialize datapoints here, to make sure that it is initialized just once.
+    unwrappedValues = fetchAllUnwrappedValues();
+  }
+
+  @Before
+  public void initNodes() {
+    executeInContext(context, () -> {
+      hashCodeNode = HashCodeAnyNode.build();
+      equalsNode = EqualsAnyNode.build();
+      return null;
+    });
+  }
+
+  @AfterClass
+  public static void disposeContext() {
+    context.close();
+  }
+
+  /**
+   * All values are static field, instead of method. Methods annotated with {@code DataPoints}
+   * may be called multiple times, therefore, we should avoid this annotation for expensive methods.
+   */
+  @DataPoints
+  public static Object[] unwrappedValues;
+
+  private static Object[] fetchAllUnwrappedValues() {
+    var valGenerator = ValuesGenerator.create(
+        context,
+        ValuesGenerator.Language.ENSO,
+        ValuesGenerator.Language.JAVA,
+        ValuesGenerator.Language.JAVASCRIPT,
+        ValuesGenerator.Language.PYTHON
+    );
+    List<Value> values = new ArrayList<>();
+    values.addAll(valGenerator.numbers());
+    values.addAll(valGenerator.booleans());
+    values.addAll(valGenerator.textual());
+    values.addAll(valGenerator.arrayLike());
+    values.addAll(valGenerator.vectors());
+    values.addAll(valGenerator.maps());
+    values.addAll(valGenerator.multiLevelAtoms());
+    values.addAll(valGenerator.timesAndDates());
+    values.addAll(valGenerator.timeZones());
+    values.addAll(valGenerator.durations());
+    values.addAll(valGenerator.periods());
+    values.addAll(valGenerator.warnings());
+    try {
+      return values
+          .stream()
+          .map(value -> unwrapValue(context, value))
+          .collect(Collectors.toList())
+          .toArray(new Object[]{});
+    } catch (Exception e) {
+      throw new AssertionError(e);
+    }
+  }
+
+  @Theory
+  public void hashCodeContractTheory(Object firstValue, Object secondValue) {
+    executeInContext(context, () -> {
+      long firstHash = hashCodeNode.execute(firstValue);
+      long secondHash = hashCodeNode.execute(secondValue);
+      boolean valuesAreEqual = equalsNode.execute(firstValue, secondValue);
+      // if o1 == o2 then hash(o1) == hash(o2)
+      if (valuesAreEqual) {
+        assertEquals(
+            String.format("""
+                  If two objects are same, they should have same hash codes:
+                    firstVal = %s, secondVal = %s, firstHash = %d, secondHash = %d
+                  """,
+                interop.toDisplayString(firstValue),
+                interop.toDisplayString(secondValue),
+                firstHash,
+                secondHash
+            ),
+            firstHash,
+            secondHash
+        );
+      }
+      // if hash(o1) != hash(o2) then o1 != o2
+      if (firstHash != secondHash) {
+        assertFalse(
+            "Violated rule: `if hash(o1) != hash(o2) then o1 != o2`",
+            valuesAreEqual
+        );
+      }
+      return null;
+    });
+  }
+
+  @Theory
+  public void hashCodeIsConsistent(Object value) {
+    executeInContext(context, () -> {
+      long firstHash = hashCodeNode.execute(value);
+      long secondHash = hashCodeNode.execute(value);
+      assertEquals(
+          "Hash code of an object should be consistent",
+          firstHash,
+          secondHash
+      );
+      return null;
+    });
+  }
+}

engine/runtime/src/test/java/org/enso/interpreter/test/MetaIsATest.java

@@ -15,30 +15,18 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
-public class MetaIsATest {
+public class MetaIsATest extends TestBase {
   private Context ctx;
   private Value isACheck;
 
   @Before
   public void prepareCtx() throws Exception {
-    Engine eng = Engine.newBuilder()
+    ctx = createDefaultContext();
-      .allowExperimentalOptions(true)
-      .logHandler(new ByteArrayOutputStream())
-      .option(
-        RuntimeOptions.LANGUAGE_HOME_OVERRIDE,
-        Paths.get("../../distribution/component").toFile().getAbsolutePath()
-      ).build();
-    this.ctx = Context.newBuilder()
-      .engine(eng)
-      .allowIO(true)
-      .allowAllAccess(true)
-      .build();
-    final Map<String, Language> langs = ctx.getEngine().getLanguages();
-    assertNotNull("Enso found: " + langs, langs.get("enso"));
-
     final URI uri = new URI("memory://choose.enso");
     final Source src = Source.newBuilder("enso", """
     import Standard.Base.Meta
@@ -53,6 +41,11 @@ public class MetaIsATest {
     assertTrue("it is a function", isACheck.canExecute());
   }
 
+  @After
+  public void disposeCtx() {
+    ctx.close();
+  }
+
   @Test
   public void checkNumbersAreNumber() {
     var g = ValuesGenerator.create(ctx);

engine/runtime/src/test/java/org/enso/interpreter/test/MetaObjectTest.java

@@ -21,25 +21,22 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
+
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
-public class MetaObjectTest {
+public class MetaObjectTest extends TestBase {
   private Context ctx;
 
   @Before
-  public void prepareCtx() throws Exception {
+  public void prepareCtx() {
-    Engine eng =
+    ctx = createDefaultContext();
-        Engine.newBuilder()
+  }
-            .allowExperimentalOptions(true)
+
-            .logHandler(new ByteArrayOutputStream())
+  @After
-            .option(
+  public void disposeCtx() {
-                RuntimeOptions.LANGUAGE_HOME_OVERRIDE,
+    ctx.close();
-                Paths.get("../../distribution/component").toFile().getAbsolutePath())
-            .build();
-    this.ctx = Context.newBuilder().engine(eng).allowIO(true).allowAllAccess(true).build();
-    final Map<String, Language> langs = ctx.getEngine().getLanguages();
-    assertNotNull("Enso found: " + langs, langs.get("enso"));
   }
 
   @Test

engine/runtime/src/test/java/org/enso/interpreter/test/TestBase.java

@@ -0,0 +1,91 @@
+package org.enso.interpreter.test;
+
+import static org.junit.Assert.assertNotNull;
+
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.TruffleObject;
+import com.oracle.truffle.api.library.ExportLibrary;
+import com.oracle.truffle.api.library.ExportMessage;
+import java.io.ByteArrayOutputStream;
+import java.nio.file.Paths;
+import java.util.Map;
+import java.util.concurrent.Callable;
+import org.enso.polyglot.RuntimeOptions;
+import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.Language;
+import org.graalvm.polyglot.Source;
+import org.graalvm.polyglot.Value;
+import org.graalvm.polyglot.proxy.ProxyExecutable;
+
+public abstract class TestBase {
+  protected static Context createDefaultContext() {
+    var context =
+        Context.newBuilder("enso")
+            .allowExperimentalOptions(true)
+            .allowIO(true)
+            .allowAllAccess(true)
+            .logHandler(new ByteArrayOutputStream())
+            .option(
+                RuntimeOptions.LANGUAGE_HOME_OVERRIDE,
+                Paths.get("../../distribution/component").toFile().getAbsolutePath())
+            .build();
+    final Map<String, Language> langs = context.getEngine().getLanguages();
+    assertNotNull("Enso found: " + langs, langs.get("enso"));
+    return context;
+  }
+
+  /**
+   * Executes the given callable in the given context. A necessity for executing artificially
+   * created Truffle ASTs.
+   *
+   * @return Object returned from {@code callable} wrapped in {@link Value}.
+   */
+  protected static Value executeInContext(Context ctx, Callable<Object> callable) {
+    // Force initialization of the context
+    ctx.eval("enso", "42");
+    ctx.getPolyglotBindings()
+        .putMember(
+            "testSymbol",
+            (ProxyExecutable)
+                (Value... args) -> {
+                  try {
+                    return callable.call();
+                  } catch (Exception e) {
+                    throw new AssertionError(e);
+                  }
+                });
+    return ctx.getPolyglotBindings().getMember("testSymbol").execute();
+  }
+
+  /**
+   * Unwraps the `receiver` field from the Value. This is a hack to allow us to test execute methods
+   * of artificially created ASTs, e.g., single nodes.
+   *
+   * <p>Does something similar to what {@link
+   * com.oracle.truffle.tck.DebuggerTester#getSourceImpl(Source)} does, but uses a different hack
+   * than reflective access.
+   */
+  protected static Object unwrapValue(Context ctx, Value value) {
+    var unwrapper = new Unwrapper();
+    var unwrapperValue = ctx.asValue(unwrapper);
+    unwrapperValue.execute(value);
+    assertNotNull(unwrapper.args);
+    return unwrapper.args[0];
+  }
+
+  @ExportLibrary(InteropLibrary.class)
+  static final class Unwrapper implements TruffleObject {
+    Object[] args;
+
+    @ExportMessage
+    Object execute(Object[] args) {
+      this.args = args;
+      return this;
+    }
+
+    @ExportMessage
+    boolean isExecutable() {
+      return true;
+    }
+  }
+}

engine/runtime/src/test/java/org/enso/interpreter/test/ValuesGenerator.java

@@ -1,7 +1,15 @@
 package org.enso.interpreter.test;
 
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.time.Duration;
 import java.time.LocalDate;
 import java.time.LocalTime;
+import java.time.Period;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.EnumSet;
@@ -9,12 +17,10 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.TimeZone;
 import org.graalvm.polyglot.Context;
 import org.graalvm.polyglot.PolyglotException;
 import org.graalvm.polyglot.Value;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
 
 /**
  * The purpose of this class is to generate various values needed for other
@@ -175,6 +181,12 @@ class ValuesGenerator {
     """, "Vector").type();
   }
 
+  public Value typeMap() {
+    return v("typeMap", """
+    import Standard.Base.Data.Map.Map
+    """, "Map").type();
+  }
+
   public Value typeWarning() {
     return v("typeWarning", """
     import Standard.Base.Warning.Warning
@@ -236,7 +248,9 @@ class ValuesGenerator {
       fac s n = if n <= 1 then s else
           @Tail_Call fac n*s n-1
       """, "fac 1 100").type());
-
+      collect.add(v(null, "", "123 * 10^40").type());
+      collect.add(v(null, "", "123 * 10^40 + 0.0").type());
+      collect.add(v(null, "", "123 * 10^40 + 1.0").type());
     }
 
     if (languages.contains(Language.JAVA)) {
@@ -257,6 +271,8 @@ class ValuesGenerator {
   public List<Value> textual() {
     var collect = new ArrayList<Value>();
     if (languages.contains(Language.ENSO)) {
+      // TODO: Add once PR #3956 is merged
+      //collect.add(v(null, "", "''").type());
       collect.add(v(null, "", "'fourty two'").type());
       collect.add(v(null, "", "'?'").type());
       collect.add(v(null, "", """
@@ -269,7 +285,14 @@ class ValuesGenerator {
 
     if (languages.contains(Language.JAVA)) {
       collect.add(ctx.asValue("fourty four from Java"));
-      // collect.add(ctx.asValue('J'));
+      collect.add(ctx.asValue("♥"));
+      collect.add(ctx.asValue("吰 abcde 1"));
+      collect.add(ctx.asValue("1234"));
+      collect.add(ctx.asValue("\t"));
+      collect.add(ctx.asValue("\n"));
+      collect.add(ctx.asValue("\r"));
+      collect.add(ctx.asValue("\r\t \t\r"));
+      collect.add(ctx.asValue("J"));
     }
 
     for (var v : collect) {
@@ -297,7 +320,7 @@ class ValuesGenerator {
     return collect;
   }
 
-  public List<Value> times() {
+  public List<Value> timesAndDates() {
     var collect = new ArrayList<Value>();
     if (languages.contains(Language.ENSO)) {
       collect.add(v(null, "import Standard.Base.Data.Time.Date.Date", "Date.now").type());
@@ -321,6 +344,98 @@ class ValuesGenerator {
     return collect;
   }
 
+  public List<Value> timeZones() {
+    var collect = new ArrayList<Value>();
+    if (languages.contains(Language.ENSO)) {
+      for (var expr : List.of(
+          "Time_Zone.new",
+          "Time_Zone.system",
+          "Time_Zone.local",
+          "Time_Zone.utc",
+          "Time_Zone.new 1 2 3",
+          "Time_Zone.parse 'Europe/Moscow'",
+          "Time_Zone.parse 'Europe/London'",
+          "Time_Zone.parse 'CET'"
+      )) {
+        collect.add(v(null, "import Standard.Base.Data.Time.Time_Zone.Time_Zone", expr).type());
+      }
+    }
+    if (languages.contains(Language.JAVA)) {
+      for (var javaValue : List.of(
+          TimeZone.getTimeZone("America/Los_Angeles"),
+          TimeZone.getTimeZone(ZoneId.systemDefault()),
+          TimeZone.getTimeZone(ZoneId.ofOffset("GMT", ZoneOffset.ofHours(2))),
+          TimeZone.getTimeZone(ZoneId.ofOffset("GMT", ZoneOffset.ofHoursMinutes(14, 45))),
+          TimeZone.getTimeZone(ZoneId.ofOffset("UTC", ZoneOffset.ofHours(-15)))
+      )) {
+        collect.add(ctx.asValue(javaValue));
+      }
+    }
+    return collect;
+  }
+
+  public List<Value> durations() {
+    var collect = new ArrayList<Value>();
+    if (languages.contains(Language.ENSO)) {
+      for (var expr : List.of(
+          "Duration.zero",
+          "Duration.new 1",
+          "Duration.new 1 1",
+          "Duration.new nanoseconds=900",
+          "Duration.new minutes=900",
+          "Duration.between (Date_Time.new 2022 01 01) (Date_Time.new 2022 02 02)",
+          "Duration.between (Date_Time.new 2022 01 01) (Date_Time.new 2022 02 02) timezone_aware=False"
+      )) {
+        collect.add(v(null, """
+                                  import Standard.Base.Data.Time.Duration.Duration
+                                  import Standard.Base.Data.Time.Date_Time.Date_Time
+                                  from Standard.Base.Data.Boolean.Boolean import False
+                                  """, expr).type());
+      }
+    }
+    if (languages.contains(Language.JAVA)) {
+      for (var javaValue : List.of(
+          Duration.ofHours(1),
+          Duration.ofHours(0),
+          Duration.ofSeconds(600),
+          Duration.ofNanos(9784),
+          Duration.ZERO
+      )) {
+        collect.add(ctx.asValue(javaValue));
+      }
+    }
+    collect.forEach(value -> assertTrue("Is duration: " + value, value.isDuration()));
+    return collect;
+  }
+
+  public List<Value> periods() {
+    var collect = new ArrayList<Value>();
+    if (languages.contains(Language.ENSO)) {
+      for (var expr : List.of(
+          "Period.new",
+          "Period.new 1",
+          "Period.new 1 14",
+          "Period.new days=568",
+          "Period.new years=23451"
+      )) {
+        collect.add(v(null, "import Standard.Base.Data.Time.Period.Period", expr).type());
+      }
+    }
+    if (languages.contains(Language.JAVA)) {
+      for (var javaValue : List.of(
+          Period.ZERO,
+          Period.ofDays(12),
+          Period.ofDays(65),
+          Period.ofMonths(13),
+          Period.of(12, 4, 60),
+          Period.ofYears(23410)
+      )) {
+        collect.add(ctx.asValue(javaValue));
+      }
+    }
+    return collect;
+  }
+
   public List<Value> arrayLike() {
     var collect = new ArrayList<Value>();
     if (languages.contains(Language.ENSO)) {
@@ -347,6 +462,83 @@ class ValuesGenerator {
     return collect;
   }
 
+  public List<Value> vectors() {
+    var collect = new ArrayList<Value>();
+    if (languages.contains(Language.ENSO)) {
+      collect.add(v(null, "", "[1,2,3]").type());
+      collect.add(v(null, "", "[]").type());
+      collect.add(v(null, "", "['a', 2, 0]").type());
+      collect.add(v(null, "", "['a', 'b', 'c']").type());
+      collect.add(v(null, "from Standard.Base.Nothing import Nothing", "[Nothing, Nothing]").type());
+      collect.add(v(null, "from Standard.Base.Nothing import Nothing", "[Nothing, 'fff', 0, Nothing]").type());
+    }
+    return collect;
+  }
+
+  public List<Value> maps() {
+    var collect = new ArrayList<Value>();
+    if (languages.contains(Language.ENSO)) {
+      var imports = """
+          import Standard.Base.Data.Map.Map
+          import Standard.Base.Nothing.Nothing
+          """;
+      for (var expr : List.of(
+          "Map.empty",
+          "Map.singleton Nothing Nothing",
+          "Map.singleton Nothing 'my_value'",
+          "Map.singleton 'my_value' Nothing",
+          "Map.singleton 1 1",
+          "Map.singleton 'C' 3",
+          "Map.singleton 'C' 43",
+          "Map.empty.insert 'A' 10 . insert 'B' 20",
+          // ((int) 'A') + ((int) 'B') = 131 ; codePoint(131) = \203
+          "Map.singleton '\203' 30",
+          "Map.singleton Map.empty 1",
+          "Map.singleton Map.empty Map.empty",
+          "Map.empty.insert 1 1 . insert 2 2",
+          "Map.empty.insert Nothing 'val' . insert 'key' 42",
+          "Map.empty.insert 'A' 1 . insert 'B' 2 . insert 'C' 3",
+          "Map.empty.insert 'C' 3 . insert 'B' 2 . insert 'A' 1"
+      )) {
+        collect.add(v(null, imports, expr).type());
+      }
+    }
+    return collect;
+  }
+
+  public List<Value> multiLevelAtoms() {
+    var collect = new ArrayList<Value>();
+    if (languages.contains(Language.ENSO)) {
+      var nodeTypeDef = """
+          type Node
+              C1 f1
+              C2 f1 f2
+              C3 f1 f2 f3
+              Nil
+              Value value
+          """;
+      for (var expr : List.of(
+          "Node.C2 Node.Nil (Node.Value 42)",
+          "Node.C2 (Node.Value 42) Node.Nil",
+          "Node.Nil",
+          "Node.Value 42",
+          "Node.Value 2",
+          "Node.Value 2.0",
+          "Node.C1 (Node.Value 42)",
+          "Node.C1 Node.Nil",
+          "Node.C3 Node.Nil (Node.Value 42) Node.Nil",
+          "Node.C3 (Node.Value 42) Node.Nil Node.Nil",
+          "Node.C3 Node.Nil Node.Nil Node.Nil",
+          "Node.C2 (Node.C2 (Node.C1 Node.Nil) (Node.C1 (Node.C1 Node.Nil))) (Node.C2 (Node.C3 (Node.Nil) (Node.Value 22) (Node.Nil)) (Node.C2 (Node.Value 22) (Node.Nil)))",
+          "Node.C2 (Node.C2 (Node.C1 Node.Nil) (Node.C1 Node.Nil)) (Node.C2 (Node.C3 (Node.Nil) (Node.Value 22) (Node.Nil)) (Node.C2 (Node.Value 22) (Node.Nil)))",
+          "Node.C2 (Node.C2 (Node.C1 Node.Nil) (Node.C1 Node.Nil)) (Node.C2 (Node.C3 (Node.Nil) (Node.Nil) (Node.Value 22)) (Node.C2 (Node.Value 22) (Node.Nil)))"
+      )) {
+        collect.add(v(null, nodeTypeDef, expr).type());
+      }
+    }
+    return collect;
+  }
+
   public List<Value> functions() {
     var collect = new ArrayList<Value>();
     if (languages.contains(Language.ENSO)) {

lib/scala/interpreter-dsl/src/main/java/org/enso/interpreter/dsl/builtins/TypeWithKind.java

@@ -43,6 +43,7 @@ public record TypeWithKind(String baseType, TypeKind kind) {
                     "org.enso.interpreter.runtime.callable.function.Function",
                     "org.enso.interpreter.runtime.data.Array",
                     "org.enso.interpreter.runtime.data.Vector",
+                    "org.enso.interpreter.runtime.data.hash.EnsoHashMap",
                     "org.enso.interpreter.runtime.data.ArrayOverBuffer",
                     "org.enso.interpreter.runtime.data.ArrayProxy",
                     "org.enso.interpreter.runtime.data.EnsoFile",

test/Benchmarks/src/Vector/Distinct.enso

@@ -12,13 +12,13 @@ polyglot java import org.enso.base.Time_Utils
 ## Bench Utilities ============================================================
 
 iter_size = 100
-num_iterations = 10
+num_iterations = 20
 
 # The Benchmarks ==============================================================
 
 bench =
-    random_vec = Utils.make_random_vec 10000
+    random_vec = Utils.make_random_vec 100000
-    uniform_vec = Base.Vector.fill 10000 1
+    uniform_vec = Base.Vector.fill 100000 1
 
     random_text_vec = random_vec.map .to_text
     uniform_text_vec = random_vec.map .to_text

test/Geo_Tests/src/Geo_Spec.enso

@@ -32,7 +32,7 @@ spec =
         Test.specify "should allow converting a GeoJSON array of features into a table" <|
             fields = ['foo', 'bar', 'baz', 'longitude', 'elevation']
             t = Geo.geo_json_to_table (geo_json.get "features") fields
-            t.columns.map .name . should_equal fields
+            t.columns.map .name . should_contain_the_same_elements_as fields
             t.at 'foo' . to_vector . should_equal [1, 2]
             t.at 'bar' . to_vector . should_equal ['value2', Nothing]
             t.at 'baz' . to_vector . should_equal [Nothing, 3]
@@ -42,7 +42,7 @@ spec =
         Test.specify "should allow converting a GeoJSON object into a table with provided fields" <|
             fields = ['foo', 'bar', 'longitude']
             t = Geo.geo_json_to_table geo_json fields
-            t.columns.map .name . should_equal fields
+            t.columns.map .name . should_contain_the_same_elements_as fields
             t.at 'foo' . to_vector . should_equal [1, 2]
             t.at 'bar' . to_vector . should_equal ['value2', Nothing]
             t.at 'longitude' . to_vector . should_equal [-118.58, 10.11]
@@ -50,7 +50,7 @@ spec =
         Test.specify "should allow converting a GeoJSON object into a table containing all available fields" <|
             fields = ['bar', 'baz', 'elevation', 'foo',  'latitude', 'longitude']
             t = Geo.geo_json_to_table geo_json
-            t.columns.map .name . should_equal fields
+            t.columns.map .name . should_contain_the_same_elements_as fields
             t.at 'foo' . to_vector . should_equal [1, 2]
             t.at 'bar' . to_vector . should_equal ['value2', Nothing]
             t.at 'baz' . to_vector . should_equal [Nothing, 3]

test/Table_Tests/src/Common_Table_Operations/Select_Columns_Spec.enso

@@ -84,7 +84,10 @@ spec setup =
             action = table.select_columns selector on_problems=_
             tester = expect_column_names ["foo", "bar"]
             problems = [Input_Indices_Already_Matched.Error [-7, 1]]
-            Problems.test_problem_handling action problems tester
+            err_checker err =
+                err.catch.should_be_a Input_Indices_Already_Matched.Error
+                err.catch.indices.should_contain_the_same_elements_as [-7, 1]
+            Problems.test_advanced_problem_handling action err_checker (x-> x) tester
 
         Test.specify "should correctly handle problems: duplicate names" <|
             selector = By_Name ["foo", "foo"]
@@ -475,22 +478,28 @@ spec setup =
             map = Column_Name_Mapping.By_Name (Map.from_vector [["alpha", "FirstColumn"], ["omicron", "Another"], [weird_name, "Fixed"]])
             action = table.rename_columns map on_problems=_
             tester = expect_column_names ["FirstColumn", "beta", "gamma", "delta"]
-            problems = [Missing_Input_Columns.Error [weird_name, "omicron"]]
+            err_checker err =
-            Problems.test_problem_handling action problems tester
+                err.catch.should_be_a Missing_Input_Columns.Error
+                err.catch.criteria.should_contain_the_same_elements_as ["omicron", weird_name]
+            Problems.test_advanced_problem_handling action err_checker (x-> x) tester
 
         Test.specify "should correctly handle problems: out of bounds indices" <|
             map = Column_Name_Mapping.By_Index (Map.from_vector [[0, "FirstColumn"], [-1, "Another"], [100, "Boo"], [-200, "Nothing"], [300, "Here"]])
             action = table.rename_columns map on_problems=_
             tester = expect_column_names ["FirstColumn", "beta", "gamma", "Another"]
-            problems = [Column_Indexes_Out_Of_Range.Error [-200, 100, 300]]
+            err_checker err =
-            Problems.test_problem_handling action problems tester
+                err.catch.should_be_a Column_Indexes_Out_Of_Range.Error
+                err.catch.indexes.should_contain_the_same_elements_as [-200, 100, 300]
+            Problems.test_advanced_problem_handling action err_checker (x-> x) tester
 
         Test.specify "should correctly handle problems: aliased indices" <|
-            map = Column_Name_Mapping.By_Index (Map.from_vector [[1, "FirstColumn"], [-3, "Another"]])
+            map = Column_Name_Mapping.By_Index (Map.from_vector [[1, "FirstColumn"], [-3, "FirstColumn"]])
             action = table.rename_columns map on_problems=_
-            tester = expect_column_names ["alpha", "Another", "gamma", "delta"]
+            tester = expect_column_names ["alpha", "FirstColumn", "gamma", "delta"]
-            problems = [Input_Indices_Already_Matched.Error [1]]
+            err_checker err =
-            Problems.test_problem_handling action problems tester
+                err.catch.should_be_a Input_Indices_Already_Matched.Error
+                (err.catch.indices.contains 1 || err.catch.indices.contains -3) . should_be_true
+            Problems.test_advanced_problem_handling action err_checker (x-> x) tester
 
         Test.specify "should correctly handle problems: invalid names ''" <|
             map = Column_Name_Mapping.By_Index (Map.from_vector [[1, ""]])
@@ -517,5 +526,7 @@ spec setup =
             map = Column_Name_Mapping.By_Position ["A", "B", "C", "D", "E", "F"]
             action = table.rename_columns map on_problems=_
             tester = expect_column_names ["A", "B", "C", "D"]
-            problems = [Too_Many_Column_Names_Provided.Error ["E", "F"]]
+            err_checker err =
-            Problems.test_problem_handling action problems tester
+                err.catch.should_be_a Too_Many_Column_Names_Provided.Error
+                err.catch.column_names.should_contain_the_same_elements_as ["E", "F"]
+            Problems.test_advanced_problem_handling action err_checker (x-> x) tester

test/Tests/src/Data/Map_Spec.enso

@@ -1,38 +1,191 @@
 from Standard.Base import all
 import Standard.Base.Error.No_Such_Key.No_Such_Key
+import Standard.Base.Data.Time.Date_Time.Date_Time
+from Standard.Base.Data.Map import Map
 
 from Standard.Test import Test, Test_Suite
 import Standard.Test.Extensions
 
-spec = Test.group "Maps" <|
+polyglot java import java.nio.file.Path as JavaPath
-    m = Map.empty . insert 1 2 . insert 2 4
+polyglot java import java.util.Map as JavaMap
-    expected = Map.empty . insert "1" 4 . insert "2" 8
+
-    m.transform (k -> v -> [k.to_text, v*2]) . should_equal expected
+foreign js js_str str = """
+    return new String(str)
+
+foreign js js_empty_dict = """
+    return new Map()
+
+foreign python py_empty_dict = """
+    return {}
+
+foreign js js_dict_from_vec vec = """
+    dict = new Map()
+    for (let i = 0; i < vec.length; i += 2) {
+        dict.set(vec[i], vec[i+1])
+    }
+    return dict
+
+foreign python py_dict_from_vec vec = """
+    d = {}
+    for i in range(0, len(vec), 2):
+        d[vec[i]] = vec[i + 1]
+    return d
+
+foreign python py_dict_from_map map = """
+    d = dict()
+    for key in map.__iter__():
+        d[key] = map[key]
+    return d
+
+foreign python py_vec_from_map map = """
+    vec = []
+    for key in map.__iter__():
+        value = map[key]
+        vec.append([key, value])
+    return vec
+
+# Should throw error - updating immutable map from Enso
+foreign python py_update_dict map key val = """
+    map[key] = val
+
+foreign python py_wrapper obj = """
+    class MyClass:
+        def __init__(self, obj):
+            self.data = obj
+    return MyClass(obj)
+
+pending_python_missing = if Polyglot.is_language_installed "python" then Nothing else """
+    Can't run Python tests, Python is not installed.
+
+type Child
+    Value data
+
+type Parent
+    Value child
+
+type GrandParent
+    Value parent
+
+spec =
+    Test.group "Enso maps" <|
         Test.specify "should allow checking for emptiness" <|
             empty_map = Map.empty
             non_empty = Map.empty . insert "foo" 1234
             empty_map.is_empty . should_be_true
             non_empty.is_empty . should_be_false
+
+        Test.specify "should compare two hash maps" <|
+            (Map.singleton "a" 1).should_equal (Map.singleton "a" 1)
+            (Map.singleton "b" 2).should_not_equal (Map.singleton "a" 1)
+            Map.empty.should_equal Map.empty
+            Map.empty.should_not_equal (Map.singleton "a" 1)
+            (Map.empty.insert "a" 1 . insert "b" 2).should_equal (Map.empty.insert "b" 2 . insert "a" 1)
+
         Test.specify "should allow checking for non emptiness" <|
             empty_map = Map.empty
             non_empty = Map.empty . insert "foo" 1234
             empty_map.not_empty . should_be_false
             non_empty.not_empty . should_be_true
+
         Test.specify "should allow checking its size" <|
             empty_map = Map.empty
             non_empty = Map.singleton "a" "b" . insert "x" "y"
             empty_map.size . should_equal 0
             non_empty.size . should_equal 2
+
+        Test.specify "should support arbitrary atoms as keys" <|
+            map = Map.singleton (Pair.new "one" "two") 42
+            (map.get (Pair.new "one" "two")).should_equal 42
+            (map.get (Pair.new "A" "B")).should_equal Nothing
+            (map.get (Pair.new "two" "two")).should_equal Nothing
+
+        Test.specify "should use proper hash code for keys" <|
+            single_key_map key = Map.singleton key 42
+            grand_parent_1 = GrandParent.Value (Parent.Value (Child.Value 2))
+            grand_parent_2 = GrandParent.Value (Parent.Value (Child.Value 2.0))
+
+            (single_key_map 2 . at 2.0) . should_equal 42
+            (single_key_map -2 . at -2.0) . should_equal 42
+            (single_key_map 'ś' . at 's\u0301') . should_equal 42
+            (single_key_map 's\u0301' . at 'ś') . should_equal 42
+            (single_key_map 'éabc' . at 'e\u0301abc') . should_equal 42
+            (single_key_map 'e\u0301abc' . at 'éabc') . should_equal 42
+            (single_key_map grand_parent_1 . at grand_parent_2) . should_equal 42
+            (single_key_map (Json.parse '{"a": 1}') . at (Json.parse '{"a": 1}')) . should_equal 42
+            (single_key_map (Child.Value 1) . at (Child.Value 1.0)) . should_equal 42
+
+        Test.specify "should support vectors as keys" <|
+            map = Map.singleton [1, "a", 2] "Value"
+            map.size.should_equal 1
+            map.get [1, "a", 2] . should_equal "Value"
+
+        Test.specify "should support dates as keys" <|
+            map = Map.empty.insert (Date.new 1993) 1 . insert (Date.new 1993 2 5) 2 . insert (Date_Time.new 1993 2 5 13 45) 3
+            map.size.should_equal 3
+            map.get (Date.new 1993 6 7) . should_equal Nothing
+            map.get (Date.new 1993) . should_equal 1
+            map.get (Date_Time.new 1993) . should_equal Nothing
+            map.get (Date.new 1993 2 5) . should_equal 2
+            map.get (Date_Time.new 1993 2 5) . should_equal Nothing
+            map.get (Date_Time.new 1993 2 5 13 45) . should_equal 3
+
+        Test.specify "should support another hash map as key" <|
+            key_map = Map.singleton (Pair.new "one" "two") 42
+            map = Map.singleton key_map 23
+            map.size.should_equal 1
+            (map.get "A").should_equal Nothing
+            (map.get key_map).should_equal 23
+            (map.get map).should_equal Nothing
+
+        Test.specify "should handle keys with standard equality semantics" <|
+            map = Map.singleton 2 "Hello"
+            (map.get 2).should_equal "Hello"
+            (map.get 2.0).should_equal "Hello"
+            (Map.singleton 2 "Hello").should_equal (Map.singleton 2.0 "Hello")
+
+        Test.specify "should handle Nothing as keys" <|
+            Map.singleton Nothing 3 . get Nothing . should_equal 3
+            Map.singleton Nothing 1 . insert Nothing 2 . get Nothing . should_equal 2
+
+        Test.specify "should handle Nothing as values" <|
+            Map.singleton 1 Nothing . at 1 . should_equal Nothing
+            Map.singleton Nothing Nothing . at Nothing . should_equal Nothing
+
+        Test.specify "should support rewriting values with same keys" <|
+            map = Map.empty.insert "a" 1 . insert "a" 42
+            map.size.should_equal 1
+            map.get "a" . should_equal 42
+
+        Test.specify "should allow storing atoms as values" <|
+            json = Json.parse '{"a": 1}'
+            pair = Pair.new "first" "second"
+            map = Map.empty.insert 0 json . insert 1 pair
+            map.get 0 . should_equal json
+            map.get 1 . should_equal pair
+
+        Test.specify "should not drop warnings from keys" <|
+            key = Warning.attach "my_warn" "my_key"
+            map = Map.singleton key 42
+            (Warning.get_all (map.keys.at 0)).length . should_equal 1
+
+        Test.specify "should not drop warnings from values" <|
+            val = Warning.attach "my_warn" "my_val"
+            map = Map.singleton 42 val
+            (Warning.get_all (map.values.at 0)).length . should_equal 1
+
         Test.specify "should convert the whole map to a vector" <|
             m = Map.empty . insert 0 0 . insert 3 -5 . insert 1 2
-        m.to_vector.should_equal [[0, 0], [1, 2], [3, -5]]
+            m.to_vector.should_equal [[0, 0], [3, -5], [1, 2]]
+
         Test.specify "should allow building the map from a vector" <|
             expected = Map.empty . insert 0 0 . insert 3 -5 . insert 1 2
             vec = [[0, 0], [3, -5], [1, 2]]
             Map.from_vector vec . should_equal expected
+
         Test.specify "should define a well-defined text conversion" <|
             m = Map.empty . insert 0 0 . insert 3 -5 . insert 1 2
-        m.to_text . should_equal "[[0, 0], [1, 2], [3, -5]]"
+            m.to_text . should_equal "{0=0, 3=-5, 1=2}"
+
         Test.specify "should define structural equality" <|
             map_1 = Map.empty . insert "1" 2 . insert "2" "1"
             map_2 = Map.empty . insert "1" 2 . insert "2" "1"
@@ -40,89 +193,284 @@ spec = Test.group "Maps" <|
             map_1==map_2 . should_be_true
             map_1==map_3 . should_be_false
             map_2==map_3 . should_be_false
+
         Test.specify "should allow inserting and looking up values" <|
             m = Map.empty . insert "foo" 134 . insert "bar" 654 . insert "baz" "spam"
             m.at "foo" . should_equal 134
             m.at "bar" . should_equal 654
             m.at "baz" . should_equal "spam"
             (m.at "nope").should_fail_with No_Such_Key.Error
+
         Test.specify "should support get" <|
             m = Map.empty . insert 2 3
             m.get 2 0 . should_equal 3
             m.get 1 10 . should_equal 10
             m.get 2 (Panic.throw "missing") . should_equal 3
+
+        Test.specify "should allow getting a vector of the keys" <|
+            m = Map.empty . insert 1 2 . insert 2 4
+            m.keys . should_equal [1, 2]
+
+        Test.specify "should allow getting a vector of the values" <|
+            m = Map.empty . insert 1 2 . insert 2 4
+            m.values . should_equal [2, 4]
+
         Test.specify "should support contains_key" <|
             m = Map.empty . insert 2 3
             m.contains_key 2 . should_be_true
             m.contains_key 1 . should_be_false
+
         Test.specify "should allow transforming the map" <|
             m = Map.empty . insert 1 2 . insert 2 4
             expected = Map.empty . insert "1" 4 . insert "2" 8
             m.transform (k -> v -> [k.to_text, v*2]) . should_equal expected
+
         Test.specify "should allow mapping over values" <|
             m = Map.empty . insert 1 2 . insert 2 4
             expected = Map.empty . insert 1 4 . insert 2 8
             m.map (v -> v*2) . should_equal expected
+
         Test.specify "should allow mapping over keys" <|
             m = Map.empty . insert 1 2 . insert 2 4
             expected = Map.empty . insert 2 2 . insert 4 4
             m.map_keys (k -> k*2) . should_equal expected
+
         Test.specify "should allow mapping with keys" <|
             m = Map.empty . insert 1 2 . insert 2 4
             expected = Map.empty . insert 1 3 . insert 2 6
             m.map_with_key (k -> v -> k + v) . should_equal expected
+
         Test.specify "should allow iterating over each value" <|
             m = Map.empty . insert 1 2 . insert 2 4
             vec = Vector.new_builder
             expected_vec = [2, 4]
             m.each (v -> vec.append v)
             vec.to_vector . should_equal expected_vec
+
         Test.specify "should allow iterating over each key-value pair" <|
             m = Map.empty . insert 1 2 . insert 2 4
             vec = Vector.new_builder
             expected_vec = [3, 6]
             m.each_with_key (k -> v -> vec.append (k+v))
             vec.to_vector . should_equal expected_vec
+
         Test.specify "should allow folding over the values" <|
             m = Map.empty . insert 1 2 . insert 2 4
             m.fold 0 (+) . should_equal 6
+
         Test.specify "should allow folding over the key-value pairs" <|
             m = Map.empty . insert 1 2 . insert 2 4
             m.fold_with_key 0 (l -> k -> v -> l + k + v) . should_equal 9
-    Test.specify "should allow getting a vector of the keys" <|
+
-        m = Map.empty . insert 1 2 . insert 2 4
-        m.keys . should_equal [1, 2]
-    Test.specify "should allow getting a vector of the values" <|
-        m = Map.empty . insert 1 2 . insert 2 4
-        m.values . should_equal [2, 4]
-    Test.specify "should be able to get the first key value pair" <|
-        m = Map.empty . insert 1 2 . insert 2 4
-        pair = m.first
-        pair.first . should_equal 1
-        pair.second . should_equal 2
-    Test.specify "should be able to get the first key value pair of an empty map" <|
-        m = Map.empty
-        m.first . should_equal Nothing
-    Test.specify "should be able to get the last key value pair" <|
-        m = Map.empty . insert 1 2 . insert 2 4
-        pair = m.last
-        pair.first . should_equal 2
-        pair.second . should_equal 4
-    Test.specify "should be able to get the last key value pair of an empty map" <|
-        m = Map.empty
-        m.last . should_equal Nothing
-    Test.specify "should be able to add a Nothing key to the map" <|
-        m = Map.empty . insert Nothing 1
-        m.last . should_equal (Pair.new Nothing 1)
         Test.specify "should be able to add a Nothing key to the map of Text" <|
             m = Map.empty . insert "A" 2 . insert Nothing 1 . insert "B" 3
             m.at "A" . should_equal 2
             m.at "B" . should_equal 3
             m.at Nothing . should_equal 1
+
         Test.specify "should be able to add a Nothing key to the map of Integer" <|
             m = Map.empty . insert 100 2 . insert Nothing 1 . insert 200 3
             m.at 100 . should_equal 2
             m.at 200 . should_equal 3
             m.at Nothing . should_equal 1
 
+        Test.specify "should be able to remove entries (1)" <|
+            m1 = Map.empty.insert "A" 1 . insert "B" 2
+            m2 = m1.remove "B"
+            m2.get "A" . should_equal 1
+            m2.remove "A" . should_equal Map.empty
+            Test.expect_panic_with (m1.remove "foo") Any
+
+        Test.specify "should be able to remove entries (2)" <|
+            m1 = Map.empty.insert "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m1.insert "C" 3
+            m2.remove "A" . to_vector . should_equal [["B", 2]]
+            m2.remove "B" . to_vector . should_equal [["A", 1]]
+            m3.remove "A" . to_vector . should_equal [["C", 3]]
+            m3.remove "C" . to_vector . should_equal [["A", 1]]
+
+        Test.specify "should be able to remove entries (3)" <|
+            m = Map.empty.insert "A" 1 . insert "B" 2 . insert "C" 3
+            m.remove "B" . should_equal (Map.singleton "A" 1 . insert "C" 3)
+
+    Test.group "Polyglot keys and values" <|
+        Test.specify "should support polyglot keys" <|
+            map = Map.singleton (js_str "A") 42
+            map.size.should_equal 1
+            map.get "A" . should_equal 42
+            map.get (js_str "A") . should_equal 42
+
+        Test.specify "should support host objects as keys" <|
+            # JavaPath has proper implementation of hashCode
+            map = Map.singleton (JavaPath.of "/home/user/file.txt") 42
+            map.get "X" . should_equal Nothing
+            map.get "A" . should_equal Nothing
+            map.get (JavaPath.of "/home/user/file.txt") . should_equal 42
+
+        Test.specify "should support Python objects as keys" pending=pending_python_missing <|
+            py_obj = py_wrapper 42
+            map = Map.singleton py_obj "Value"
+            map.get py_obj . should_equal "Value"
+
+        Test.specify "should support Python objects as values" pending=pending_python_missing <|
+            map = Map.singleton "A" (py_wrapper 42)
+            map.get "A" . data . should_equal 42
+
+        Test.specify "should insert entries to a polyglot map" pending=pending_python_missing <|
+            dict = py_dict_from_vec ["A", 1, "B", 2]
+            dict.insert "C" 3 . keys . sort . should_equal ["A", "B", "C"]
+
+        Test.specify "should remove entries from a polyglot map" pending=pending_python_missing <|
+            dict = py_dict_from_vec ["A", 1, "B", 2]
+            dict.remove "B" . to_vector . should_equal [["A", 1]]
+
+    Test.group "non-linear inserts" <|
+        Test.specify "should handle inserts with different keys" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m1.insert "C" 3
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 1], ["C", 3]]
+
+        Test.specify "should handle inserts with same keys (1)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "A" 2
+            m3 = m1.insert "A" 3
+            m4 = m1.insert "B" 4
+            m2.to_vector.sort on=_.first . should_equal [["A", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 3]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 4]]
+
+        Test.specify "should handle inserts with same keys (2)" <|
+            m1 = Map.singleton "foo" 1
+            m2 = m1.insert "baz" 2
+            m3 = m2.insert "foo" 3
+            m1.to_vector.sort on=_.first . should_equal [['foo', 1]]
+            m2.to_vector.sort on=_.first . should_equal [['baz', 2], ['foo', 1]]
+            m3.to_vector.sort on=_.first . should_equal [['baz', 2], ['foo', 3]]
+
+        Test.specify "should handle inserts with same keys (3)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "A" 3
+            m4 = m2.insert "C" 4
+            m1.to_vector.sort on=_.first . should_equal [["A", 1]]
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 3], ["B", 2]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 4]]
+
+        Test.specify "should handle inserts with same keys (4)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "C" 3
+            m4 = m2.insert "D" 4
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 3]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["D", 4]]
+
+        Test.specify "should handle inserts with same keys (5)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "A" 3
+            m4 = m2.insert "A" 4
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 3], ["B", 2]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 4], ["B", 2]]
+
+        Test.specify "should handle inserts with same keys (6)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "C" 3
+            m4 = m2.insert "A" 4
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 3]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 4], ["B", 2]]
+
+        Test.specify "should handle inserts with same keys (7)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "C" 3
+            m4 = m3.insert "D" 4
+            m5 = m2.insert "A" 5
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 3]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 3], ["D", 4]]
+            m5.to_vector.sort on=_.first . should_equal [["A", 5], ["B", 2]]
+
+        Test.specify "should handle inserts with same keys (8)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "C" 3
+            m4 = m3.insert "A" 4
+            m5 = m2.insert "A" 5
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 3]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 4], ["B", 2], ["C", 3]]
+            m5.to_vector.sort on=_.first . should_equal [["A", 5], ["B", 2]]
+
+        Test.specify "should handle inserts with same keys (9)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "A" 3
+            m4 = m2.insert "B" 4
+            m5 = m2.insert "C" 5
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 3], ["B", 2]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 4]]
+            m5.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 5]]
+
+        Test.specify "should handle inserts with same keys (10)" <|
+            m1 = Map.singleton "A" 1
+            m2 = m1.insert "B" 2
+            m3 = m2.insert "C" 3
+            m4 = m2.insert "D" 4
+            m5 = m2.insert "E" 5
+            m2.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2]]
+            m3.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["C", 3]]
+            m4.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["D", 4]]
+            m5.to_vector.sort on=_.first . should_equal [["A", 1], ["B", 2], ["E", 5]]
+
+    Test.group "Polyglot hash maps" <|
+        Test.specify "should pass maps as immutable maps to other langs" pending=pending_python_missing <|
+            map = Map.singleton "A" 1
+            # Python's KeyError should be raised
+            Test.expect_panic_with (py_update_dict map "A" 2) Any
+            map.get "A" . should_equal 1
+
+        Test.specify "should treat JavaScript maps as Enso maps" <|
+            js_dict = js_dict_from_vec ["A", 1, "B", 2]
+            map = js_dict.insert "C" 3
+            js_dict.to_vector.should_equal [["A", 1], ["B", 2]]
+            map.to_vector.should_equal [["A", 1], ["B", 2], ["C", 3]]
+
+        Test.specify "should treat Java Map as Enso map" <|
+            sort_by_keys vec = vec.sort by=x-> y-> x.first.compare_to y.first
+            jmap = JavaMap.of "A" 1 "B" 2
+            (sort_by_keys jmap.to_vector) . should_equal [["A", 1], ["B", 2]]
+            (sort_by_keys (jmap.insert "C" 3 . to_vector)) . should_equal [["A", 1], ["B", 2], ["C", 3]]
+
+        Test.specify "should treat Python dicts as Enso maps" pending=pending_python_missing <|
+            py_dict = py_dict_from_vec ["A", 1, "B", 2]
+            map = py_dict.insert "C" 3
+            py_dict.not_empty . should_be_true
+            py_dict.to_vector.should_equal [["A", 1], ["B", 2]]
+            map.to_vector.should_equal [["A", 1], ["B", 2], ["C", 3]]
+            py_empty_dict.is_empty.should_be_true
+            py_empty_dict.insert "A" 1 . insert "A" 2 . get "A" . should_equal 2
+
+        Test.specify "should pass maps with null keys to Python and back" pending=pending_python_missing <|
+            # Python supports None as keys, Enso support Nothing as keys
+            py_dict = py_dict_from_map (Map.singleton Nothing 42)
+            py_dict.get Nothing . should_equal 42
+            py_dict.insert "A" 23 . get Nothing . should_equal 42
+            py_dict.insert Nothing 23 . get Nothing . should_equal 23
+
+        Test.specify "should treat Enso maps as Python dicts when passed to Python" pending=pending_python_missing <|
+            map1 = Map.empty.insert "A" 1 . insert "B" 2
+            py_vec_from_map map1 . should_equal [["A", 1], ["B", 2]]
+            map2 = Map.empty.insert "A" 1 . insert Nothing 2
+            py_vec_from_map map2 . should_equal [["A", 1], [Nothing, 2]]
+
+
 main = Test_Suite.run_main spec

test/Tests/src/Data/Vector_Spec.enso

@@ -641,11 +641,6 @@ spec = Test.group "Vectors" <|
         [1, 1.0, 2, 2.0].distinct . should_equal [1, 2]
         [].distinct . should_equal []
 
-    Test.specify "should throw a clean error for incomparable types" <|
-        ["a", 2].distinct . should_fail_with Incomparable_Values
-        [2, "a", Integer, "a", 2].distinct . should_fail_with Incomparable_Values
-        [Pair.new 1 2, Pair.new 3 4].distinct . should_fail_with Incomparable_Values
-
     Test.specify "should correctly handle distinct with custom types like Atoms that implement compare_to" <|
         [T.Value 1 2, T.Value 3 3, T.Value 1 2].distinct . should_equal [T.Value 1 2, T.Value 3 3]
 

test/Tests/src/Semantic/Equals_Spec.enso

@@ -3,7 +3,7 @@ from Standard.Base import all
 from Standard.Test import Test, Test_Suite
 import Standard.Test.Extensions
 
-polyglot java import java.util.HashMap
+polyglot java import java.nio.file.Path as JavaPath
 polyglot java import java.util.Random as Java_Random
 
 type CustomEqType
@@ -113,6 +113,11 @@ spec =
             (js_true == False).should_be_false
             (js_text_foo == "foo").should_be_true
 
+        Test.specify "should handle Text via NFD normalization" <|
+            ('ś' == 's\u0301') . should_be_true
+            ('e\u0301abc' == 'éabc') . should_be_true
+            ('e\u0301abc' == 'é') . should_be_false
+            ((Point.Value 'ś' 23.0) == (Point.Value 's\u0301' 23)) . should_be_true
 
         Test.specify "should dispatch to overriden `==` on atoms" <|
             child1 = Child.Value 11
@@ -136,24 +141,14 @@ spec =
             ((CustomEqType.C1 0) == (CustomEqType.C2 7 3)).should_be_false
 
         Test.specify "should dispatch to equals on host values" <|
-            java_object1 = HashMap.new
+            path1 = JavaPath.of "home" "user" . resolve "file.txt"
-            java_object1.put "a" 1
+            path2 = JavaPath.of "home" "user" "file.txt"
-            java_object1.put "b" 2
+            (path1 == path2).should_be_true
-
+            path3 = path1.resolve "subfile.txt"
-            java_object2 = HashMap.new
+            (path3 == path2).should_be_false
-            java_object2.put "b" 2
-            java_object2.put "a" 1
-
-            (java_object1 == java_object2).should_be_true
-
-            java_object2.put "c" 42
-
-            (java_object1 == java_object2).should_be_false
 
         Test.specify "should return False for different Atoms with same fields" <|
-            p1 = Point.Value 1 2
+            rect = Rect.Value (Point.Value 1 2) (Point.Value 3 4)
-            p2 = Point.Value 3 4
-            rect = Rect.Value p1 p2
             four_field = FourFieldType.Value 1 2 3 4
             (rect == four_field).should_be_false
 
@@ -161,8 +156,8 @@ spec =
             (Child == Child).should_be_true
             (Child == Point).should_be_false
             (Point == Child).should_be_false
-            (HashMap == Child).should_be_false
+            (JavaPath == Child).should_be_false
-            (Child == HashMap).should_be_false
+            (Child == JavaPath).should_be_false
             (Boolean == Any).should_be_false
             (Any == Boolean).should_be_false
             (Any == Any).should_be_true

test/Visualization_Tests/src/Scatter_Plot_Spec.enso

@@ -110,7 +110,7 @@ spec =
             json.field_names.should_equal ['data','axis']
             data = json.get 'data'
             data.length . should_equal 10
-            (data.take (First 3)).to_text . should_equal '[{"x":0,"y":225}, {"x":15,"y":0}, {"x":29,"y":196}]'
+            (data.take (First 3)).to_text . should_equal '[{"x":0,"y":225}, {"x":29,"y":196}, {"x":15,"y":0}]'
 
         Test.specify "filter the elements" <|
             vector = [0,10,20,30]