Methods on Any type and pattern matches on arbitrary values (#259)

Interpreter/src/main/java/org/enso/interpreter/Constants.java

@@ -11,6 +11,7 @@ public class Constants {
 
   public static final String THIS_ARGUMENT_NAME = "this";
   public static final String SCOPE_SEPARATOR = ".";
+  public static final String ANY_TYPE_NAME = "Any";
 
   /** Cache sizes for different AST nodes. */
   public static class CacheSizes {

Interpreter/src/main/java/org/enso/interpreter/builder/ExpressionFactory.java

@@ -26,12 +26,7 @@ import org.enso.interpreter.node.callable.ForceNodeGen;
 import org.enso.interpreter.node.callable.argument.ReadArgumentNode;
 import org.enso.interpreter.node.callable.function.CreateFunctionNode;
 import org.enso.interpreter.node.callable.function.FunctionBodyNode;
-import org.enso.interpreter.node.controlflow.CaseNode;
-import org.enso.interpreter.node.controlflow.ConstructorCaseNode;
-import org.enso.interpreter.node.controlflow.DefaultFallbackNode;
-import org.enso.interpreter.node.controlflow.FallbackNode;
-import org.enso.interpreter.node.controlflow.IfZeroNode;
-import org.enso.interpreter.node.controlflow.MatchNode;
+import org.enso.interpreter.node.controlflow.*;
 import org.enso.interpreter.node.expression.constant.ConstructorNode;
 import org.enso.interpreter.node.expression.constant.DynamicSymbolNode;
 import org.enso.interpreter.node.expression.literal.IntegerLiteralNode;
@@ -395,7 +390,7 @@ public class ExpressionFactory implements AstExpressionVisitor<ExpressionNode> {
             .map(fb -> (CaseNode) new FallbackNode(fb.visit(this)))
             .orElseGet(DefaultFallbackNode::new);
 
-    return new MatchNode(targetNode, cases, fallbackNode);
+    return MatchNodeGen.create(cases, fallbackNode, targetNode);
   }
 
   /* Note [Pattern Match Fallbacks]

Interpreter/src/main/java/org/enso/interpreter/builder/ModuleScopeExpressionFactory.java

@@ -90,10 +90,6 @@ public class ModuleScopeExpressionFactory implements AstGlobalScopeVisitor<Expre
             });
 
     for (AstMethodDef method : bindings) {
-      AtomConstructor constructor =
-          moduleScope
-              .getConstructor(method.typeName())
-              .orElseThrow(() -> new VariableDoesNotExistException(method.typeName()));
       ExpressionFactory expressionFactory =
           new ExpressionFactory(
               language,
@@ -105,7 +101,16 @@ public class ModuleScopeExpressionFactory implements AstGlobalScopeVisitor<Expre
       funNode.markTail();
       Function function =
           new Function(funNode.getCallTarget(), null, new ArgumentSchema(funNode.getArgs()));
-      moduleScope.registerMethod(constructor, method.methodName(), function);
+
+      if (method.typeName().equals(Constants.ANY_TYPE_NAME)) {
+        moduleScope.registerMethodForAny(method.methodName(), function);
+      } else {
+        AtomConstructor constructor =
+            moduleScope
+                .getConstructor(method.typeName())
+                .orElseThrow(() -> new VariableDoesNotExistException(method.typeName()));
+        moduleScope.registerMethod(constructor, method.methodName(), function);
+      }
     }
 
     ExpressionFactory factory = new ExpressionFactory(this.language, moduleScope);

Interpreter/src/main/java/org/enso/interpreter/node/callable/ApplicationNode.java

@@ -44,8 +44,9 @@ public class ApplicationNode extends ExpressionNode {
         Arrays.stream(callArguments).map(CallArgumentInfo::new).toArray(CallArgumentInfo[]::new);
 
     this.callable = callable;
+    boolean argumentsArePreExecuted = false;
     this.invokeCallableNode =
-        InvokeCallableNodeGen.create(argSchema, hasDefaultsSuspended);
+        InvokeCallableNodeGen.create(argSchema, hasDefaultsSuspended, argumentsArePreExecuted);
   }
 
   /**

Interpreter/src/main/java/org/enso/interpreter/node/callable/InvokeCallableNode.java

@@ -13,12 +13,9 @@ import org.enso.interpreter.node.callable.argument.sorter.ArgumentSorterNodeGen;
 import org.enso.interpreter.runtime.callable.UnresolvedSymbol;
 import org.enso.interpreter.runtime.callable.argument.CallArgumentInfo;
 import org.enso.interpreter.runtime.callable.argument.Thunk;
-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.error.MethodDoesNotExistException;
 import org.enso.interpreter.runtime.error.NotInvokableException;
-import org.enso.interpreter.runtime.type.TypesGen;
 
 /**
  * This class is responsible for performing the actual invocation of a given callable with its
@@ -36,6 +33,8 @@ public abstract class InvokeCallableNode extends BaseNode {
   private final boolean canApplyThis;
   private final int thisArgumentPosition;
 
+  private final boolean argumentsArePreExecuted;
+
   private final ConditionProfile methodCalledOnNonAtom = ConditionProfile.createCountingProfile();
 
   /**
@@ -44,8 +43,11 @@ public abstract class InvokeCallableNode extends BaseNode {
    * @param schema a description of the arguments being applied to the callable
    * @param hasDefaultsSuspended whether or not the invocation has the callable's default arguments
    *     (if any) suspended
+   * @param argumentsArePreExecuted whether the arguments will be provided as thunks or fully
+   *     computed values
    */
-  public InvokeCallableNode(CallArgumentInfo[] schema, boolean hasDefaultsSuspended) {
+  public InvokeCallableNode(
+      CallArgumentInfo[] schema, boolean hasDefaultsSuspended, boolean argumentsArePreExecuted) {
     boolean appliesThis = false;
     int idx = 0;
     for (; idx < schema.length; idx++) {
@@ -61,7 +63,8 @@ public abstract class InvokeCallableNode extends BaseNode {
     this.canApplyThis = appliesThis;
     this.thisArgumentPosition = idx;
 
-    boolean argumentsArePreExecuted = false;
+    this.argumentsArePreExecuted = argumentsArePreExecuted;
+
     this.argumentSorter =
         ArgumentSorterNodeGen.create(schema, hasDefaultsSuspended, argumentsArePreExecuted);
     this.methodResolverNode = MethodResolverNodeGen.create();
@@ -102,21 +105,16 @@ public abstract class InvokeCallableNode extends BaseNode {
   @Specialization
   public Object invokeDynamicSymbol(UnresolvedSymbol symbol, Object[] arguments) {
     if (canApplyThis) {
-      if (thisExecutor == null) {
-        CompilerDirectives.transferToInterpreterAndInvalidate();
-        thisExecutor = ThunkExecutorNodeGen.create(false);
-      }
-
-      Object selfArgument =
-          thisExecutor.executeThunk(((Thunk) arguments[thisArgumentPosition]));
-
-      if (methodCalledOnNonAtom.profile(TypesGen.isAtom(selfArgument))) {
-        Atom self = (Atom) selfArgument;
-        Function function = methodResolverNode.execute(symbol, self);
-        return this.argumentSorter.execute(function, arguments);
-      } else {
-        throw new MethodDoesNotExistException(selfArgument, symbol.getName(), this);
+      Object selfArgument = arguments[thisArgumentPosition];
+      if (!argumentsArePreExecuted) {
+        if (thisExecutor == null) {
+          CompilerDirectives.transferToInterpreterAndInvalidate();
+          thisExecutor = ThunkExecutorNodeGen.create(false);
+        }
+        selfArgument = thisExecutor.executeThunk((Thunk) selfArgument);
       }
+      Function function = methodResolverNode.execute(symbol, selfArgument);
+      return this.argumentSorter.execute(function, arguments);
     } else {
       throw new RuntimeException("Currying without `this` argument is not yet supported.");
     }

Interpreter/src/main/java/org/enso/interpreter/node/callable/MethodResolverNode.java

@@ -14,45 +14,56 @@ import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.error.MethodDoesNotExistException;
 
 /**
- * A node performing lookups of method definitions. Uses a polymorphic inline cache to ensure the
- * best performance.
+ * A node performing lookups of method definitions.
+ *
+ * <p>Uses a polymorphic inline cache to ensure the best performance.
+ *
+ * <p>The dispatch algorithm works by matching the kind of value the method is requested for and
+ * delegating to the proper lookup method of {@link UnresolvedSymbol}.
  */
 public abstract class MethodResolverNode extends Node {
 
-  /**
-   * DSL method to generate the actual cached code. Uses Cached arguments and performs all the logic
-   * through the DSL. Not for manual use.
-   */
-  @Specialization(guards = "isValidCache(symbol, cachedSymbol, atom, cachedConstructor)")
-  public Function resolveCached(
-      UnresolvedSymbol symbol,
-      Atom atom,
-      @CachedContext(Language.class) TruffleLanguage.ContextReference<Context> contextRef,
-      @Cached("symbol") UnresolvedSymbol cachedSymbol,
-      @Cached("atom.getConstructor()") AtomConstructor cachedConstructor,
-      @Cached("resolveMethod(cachedConstructor, cachedSymbol)") Function function) {
-    return function;
-  }
-
   /**
    * Entry point for this node.
    *
    * @param symbol Method name to resolve.
-   * @param atom Object for which to resolve the method.
+   * @param self Object for which to resolve the method.
    * @return Resolved method.
    */
-  public abstract Function execute(UnresolvedSymbol symbol, Atom atom);
+  public abstract Function execute(UnresolvedSymbol symbol, Object self);
 
-  /**
-   * Handles the actual method lookup. Not for manual use.
-   *
-   * @param cons Type for which to resolve the method.
-   * @param symbol symbol representing the method to resolve
-   * @return Resolved method definition.
-   */
-  public Function resolveMethod(
-      AtomConstructor cons,
-      UnresolvedSymbol symbol) {
+  @Specialization(guards = "isValidAtomCache(symbol, cachedSymbol, atom, cachedConstructor)")
+  Function resolveAtomCached(
+      UnresolvedSymbol symbol,
+      Atom atom,
+      @CachedContext(Language.class) TruffleLanguage.ContextReference<Context> contextRef,
+      @Cached("symbol") UnresolvedSymbol cachedSymbol,
+      @Cached("atom.getConstructor()") AtomConstructor cachedConstructor,
+      @Cached("resolveAtomMethod(cachedConstructor, cachedSymbol)") Function function) {
+    return function;
+  }
+
+  @Specialization(guards = "cachedSymbol == symbol")
+  Function resolveNumberCached(
+      UnresolvedSymbol symbol,
+      long self,
+      @CachedContext(Language.class) TruffleLanguage.ContextReference<Context> contextReference,
+      @Cached("symbol") UnresolvedSymbol cachedSymbol,
+      @Cached("resolveNumberMethod(cachedSymbol)") Function function) {
+    return function;
+  }
+
+  @Specialization(guards = "cachedSymbol == symbol")
+  Function resolveFunctionCached(
+      UnresolvedSymbol symbol,
+      Function self,
+      @CachedContext(Language.class) TruffleLanguage.ContextReference<Context> contextReference,
+      @Cached("symbol") UnresolvedSymbol cachedSymbol,
+      @Cached("resolveFunctionMethod(cachedSymbol)") Function function) {
+    return function;
+  }
+
+  Function resolveAtomMethod(AtomConstructor cons, UnresolvedSymbol symbol) {
     Function result = symbol.resolveFor(cons);
     if (result == null) {
       throw new MethodDoesNotExistException(cons, symbol.getName(), this);
@@ -60,12 +71,27 @@ public abstract class MethodResolverNode extends Node {
     return result;
   }
 
-  /**
-   * Checks the cache validity. For use by the DSL. The cache entry is valid if it's resolved for
-   * the same method name and this argument type. Not for manual use.
-   */
-  public boolean isValidCache(
-      UnresolvedSymbol symbol, UnresolvedSymbol cachedSymbol, Atom atom, AtomConstructor cachedConstructor) {
+  Function resolveNumberMethod(UnresolvedSymbol symbol) {
+    Function result = symbol.resolveForNumber();
+    if (result == null) {
+      throw new MethodDoesNotExistException("Number", symbol.getName(), this);
+    }
+    return result;
+  }
+
+  Function resolveFunctionMethod(UnresolvedSymbol symbol) {
+    Function result = symbol.resolveForFunction();
+    if (result == null) {
+      throw new MethodDoesNotExistException("Function", symbol.getName(), this);
+    }
+    return result;
+  }
+
+  boolean isValidAtomCache(
+      UnresolvedSymbol symbol,
+      UnresolvedSymbol cachedSymbol,
+      Atom atom,
+      AtomConstructor cachedConstructor) {
     return (symbol == cachedSymbol) && (atom.getConstructor() == cachedConstructor);
   }
 }

Interpreter/src/main/java/org/enso/interpreter/node/callable/argument/sorter/CachedArgumentSorterNode.java

@@ -40,8 +40,8 @@ public class CachedArgumentSorterNode extends BaseNode {
    * @param schema information on the calling argument
    * @param hasDefaultsSuspended whether or not the function to which these arguments are applied
    *     has its defaults suspended.
-   * @param ignoresArgumentExecution whether this node assumes all arguments are pre-executed and not
-   *     passed in a {@link Thunk}.
+   * @param ignoresArgumentExecution whether this node assumes all arguments are pre-executed and
+   *     not passed in a {@link Thunk}.
    * @param isTail whether this node is called from a tail call position.
    */
   public CachedArgumentSorterNode(
@@ -72,7 +72,9 @@ public class CachedArgumentSorterNode extends BaseNode {
     if (postApplicationSchema.hasOversaturatedArgs()) {
       oversaturatedCallableNode =
           InvokeCallableNodeGen.create(
-              postApplicationSchema.getOversaturatedArguments(), hasDefaultsSuspended);
+              postApplicationSchema.getOversaturatedArguments(),
+              hasDefaultsSuspended,
+              ignoresArgumentExecution);
       oversaturatedCallableNode.setTail(isTail);
     }
 
@@ -149,8 +151,7 @@ public class CachedArgumentSorterNode extends BaseNode {
           return optimiser.executeDispatch(function, mappedAppliedArguments);
         }
       } else {
-        Object evaluatedVal =
-            optimiser.executeDispatch(function, mappedAppliedArguments);
+        Object evaluatedVal = optimiser.executeDispatch(function, mappedAppliedArguments);
 
         return this.oversaturatedCallableNode.execute(
             evaluatedVal, generateOversaturatedArguments(function, arguments));

Interpreter/src/main/java/org/enso/interpreter/node/controlflow/CaseNode.java

@@ -4,16 +4,40 @@ import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.UnexpectedResultException;
 import org.enso.interpreter.node.BaseNode;
 import org.enso.interpreter.runtime.callable.atom.Atom;
+import org.enso.interpreter.runtime.callable.function.Function;
 
 /** An abstract representation of a case expression. */
 public abstract class CaseNode extends BaseNode {
   /**
-   * Executes the case expression.
+   * Executes the case expression with an atom scrutinee.
    *
    * @param frame the stack frame in which to execute
-   * @param target the constructor to destructure
+   * @param target the atom to match and destructure
    * @throws UnexpectedResultException when the result of desctructuring {@code target} can't be
    *     represented as a value of the expected return type
    */
-  public abstract void execute(VirtualFrame frame, Atom target) throws UnexpectedResultException;
+  public abstract void executeAtom(VirtualFrame frame, Atom target)
+      throws UnexpectedResultException;
+
+  /**
+   * Executes the case expression with a function scrutinee.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the function to match
+   * @throws UnexpectedResultException when the result of desctructuring {@code target} can't be
+   *     represented as a value of the expected return type
+   */
+  public abstract void executeFunction(VirtualFrame frame, Function target)
+      throws UnexpectedResultException;
+
+  /**
+   * * Executes the case expression with a number scrutinee.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the number to match
+   * @throws UnexpectedResultException when the result of desctructuring {@code target} can't be
+   *     represented as a value of the expected return type
+   */
+  public abstract void executeNumber(VirtualFrame frame, long target)
+      throws UnexpectedResultException;
 }

Interpreter/src/main/java/org/enso/interpreter/node/controlflow/ConstructorCaseNode.java

@@ -9,8 +9,9 @@ import org.enso.interpreter.node.callable.ExecuteCallNodeGen;
 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.type.TypesGen;
 
-/** An implementation of the case expression specialised to working on explicit constructors. */
+/** An implementation of the case expression specialised to working on constructors. */
 public class ConstructorCaseNode extends CaseNode {
   @Child private ExpressionNode matcher;
   @Child private ExpressionNode branch;
@@ -39,21 +40,39 @@ public class ConstructorCaseNode extends CaseNode {
   }
 
   /**
-   * Executes the case expression.
+   * Handles the atom scrutinee case.
    *
-   * <p>It has no direct return value and instead uses a {@link BranchSelectedException} to signal
-   * the correct result back to the parent of the case expression.
+   * <p>The atom's constructor is checked and if it matches the conditional branch is executed with
+   * all the atom's fields as arguments.
    *
    * @param frame the stack frame in which to execute
-   * @param target the constructor to destructure
-   * @throws UnexpectedResultException when the result of desctructuring {@code target} can't be
-   *     represented as a value of the expected return type
+   * @param target the atom to destructure
+   * @throws UnexpectedResultException
    */
-  public void execute(VirtualFrame frame, Atom target) throws UnexpectedResultException {
+  @Override
+  public void executeAtom(VirtualFrame frame, Atom target) throws UnexpectedResultException {
     AtomConstructor matcherVal = matcher.executeAtomConstructor(frame);
     if (profile.profile(matcherVal == target.getConstructor())) {
       Function function = branch.executeFunction(frame);
       throw new BranchSelectedException(executeCallNode.executeCall(function, target.getFields()));
     }
   }
+
+  /**
+   * Handles the function scrutinee case, by not matching it at all.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the function to match
+   */
+  @Override
+  public void executeFunction(VirtualFrame frame, Function target) {}
+
+  /**
+   * Handles the number scrutinee case, by not matching it at all.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the function to match
+   */
+  @Override
+  public void executeNumber(VirtualFrame frame, long target) {}
 }

Interpreter/src/main/java/org/enso/interpreter/node/controlflow/DefaultFallbackNode.java

@@ -1,7 +1,9 @@
 package org.enso.interpreter.node.controlflow;
 
 import com.oracle.truffle.api.frame.VirtualFrame;
+import com.oracle.truffle.api.nodes.UnexpectedResultException;
 import org.enso.interpreter.runtime.callable.atom.Atom;
+import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.error.InexhaustivePatternMatchException;
 
 /**
@@ -11,13 +13,49 @@ import org.enso.interpreter.runtime.error.InexhaustivePatternMatchException;
 public class DefaultFallbackNode extends CaseNode {
 
   /**
-   * Executes the case expression's error case.
+   * Executes the case expression's error case, by throwing a {@link
+   * InexhaustivePatternMatchException}.
    *
    * @param frame the stack frame in which to execute
    * @param target the constructor to destructure
    */
-  @Override
-  public void execute(VirtualFrame frame, Atom target) {
+  private void execute(VirtualFrame frame, Object target) {
     throw new InexhaustivePatternMatchException(this.getParent());
   }
+
+  /**
+   * Executes the case expression's error case, by throwing a {@link
+   * InexhaustivePatternMatchException}.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the atom to match and destructure
+   */
+  @Override
+  public void executeAtom(VirtualFrame frame, Atom target) {
+    execute(frame, target);
+  }
+
+  /**
+   * Executes the case expression's error case, by throwing a {@link
+   * InexhaustivePatternMatchException}.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the function to match
+   */
+  @Override
+  public void executeFunction(VirtualFrame frame, Function target) {
+    execute(frame, target);
+  }
+
+  /**
+   * Executes the case expression's error case, by throwing a {@link
+   * InexhaustivePatternMatchException}.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the number to match
+   */
+  @Override
+  public void executeNumber(VirtualFrame frame, long target) {
+    execute(frame, target);
+  }
 }

Interpreter/src/main/java/org/enso/interpreter/node/controlflow/FallbackNode.java

@@ -25,6 +25,11 @@ public class FallbackNode extends CaseNode {
     this.functionNode = functionNode;
   }
 
+  private void execute(VirtualFrame frame, Object target) throws UnexpectedResultException {
+    Function function = functionNode.executeFunction(frame);
+    throw new BranchSelectedException(executeCallNode.executeCall(function, new Object[0]));
+  }
+
   /**
    * Executes the case expression catch-all case.
    *
@@ -37,8 +42,40 @@ public class FallbackNode extends CaseNode {
    *     represented as a value of the expected return type
    */
   @Override
-  public void execute(VirtualFrame frame, Atom target) throws UnexpectedResultException {
-    Function function = functionNode.executeFunction(frame);
-    throw new BranchSelectedException(executeCallNode.executeCall(function, new Object[0]));
+  public void executeAtom(VirtualFrame frame, Atom target) throws UnexpectedResultException {
+    execute(frame, target);
+  }
+
+  /**
+   * Executes the case expression catch-all case.
+   *
+   * <p>It has no direct return value and instead uses a {@link BranchSelectedException} to signal
+   * the correct result back to the parent of the case expression.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the constructor to destructure
+   * @throws UnexpectedResultException when the result of desctructuring {@code target} can't be
+   *     represented as a value of the expected return type
+   */
+  @Override
+  public void executeFunction(VirtualFrame frame, Function target)
+      throws UnexpectedResultException {
+    execute(frame, target);
+  }
+
+  /**
+   * Executes the case expression catch-all case.
+   *
+   * <p>It has no direct return value and instead uses a {@link BranchSelectedException} to signal
+   * the correct result back to the parent of the case expression.
+   *
+   * @param frame the stack frame in which to execute
+   * @param target the constructor to destructure
+   * @throws UnexpectedResultException when the result of desctructuring {@code target} can't be
+   *     represented as a value of the expected return type
+   */
+  @Override
+  public void executeNumber(VirtualFrame frame, long target) throws UnexpectedResultException {
+    execute(frame, target);
   }
 }

Interpreter/src/main/java/org/enso/interpreter/node/controlflow/MatchNode.java

@@ -1,30 +1,31 @@
 package org.enso.interpreter.node.controlflow;
 
 import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.dsl.NodeChild;
+import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.nodes.ExplodeLoop;
 import com.oracle.truffle.api.nodes.UnexpectedResultException;
 import com.oracle.truffle.api.profiles.BranchProfile;
 import org.enso.interpreter.node.ExpressionNode;
 import org.enso.interpreter.runtime.callable.atom.Atom;
+import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.error.TypeError;
 
-/** A node representing a pattern match on an Atom. */
-public class MatchNode extends ExpressionNode {
-  @Child private ExpressionNode target;
+/**
+ * A node representing a pattern match on an arbitrary runtime value.
+ *
+ * <p>Has a scrutinee node and a collection of {@link CaseNode}s. The case nodes get executed one by
+ * one, until one throws an {@link BranchSelectedException}, the value of which becomes the result
+ * of this pattern match.
+ */
+@NodeChild(value = "scrutinee", type = ExpressionNode.class)
+public abstract class MatchNode extends ExpressionNode {
   @Children private final CaseNode[] cases;
   @Child private CaseNode fallback;
   private final BranchProfile typeErrorProfile = BranchProfile.create();
 
-  /**
-   * Creates a node that pattern matches on an Atom.
-   *
-   * @param target the atom to pattern match on
-   * @param cases the branches of the pattern match
-   * @param fallback the fallback case of the pattern match
-   */
-  public MatchNode(ExpressionNode target, CaseNode[] cases, CaseNode fallback) {
-    this.target = target;
+  MatchNode(CaseNode[] cases, CaseNode fallback) {
     this.cases = cases;
     this.fallback = fallback;
   }
@@ -43,21 +44,62 @@ public class MatchNode extends ExpressionNode {
     fallback.setTail(isTail);
   }
 
-  /**
-   * Executes the pattern match.
-   *
-   * @param frame the stack frame for execution
-   * @return the result of the pattern match
-   */
+  // TODO[MK]: The atom, number and function cases are very repetitive and should be refactored.
+  // It poses some engineering challenge – the approaches tried so far included passing the only
+  // changing line as a lambda and introducing a separate node between this and the CaseNodes.
+  // Both attempts resulted in a performance drop.
+
   @ExplodeLoop
-  @Override
-  public Object executeGeneric(VirtualFrame frame) {
+  @Specialization
+  Object doAtom(VirtualFrame frame, Atom atom) {
     try {
-      Atom atom = target.executeAtom(frame);
       for (CaseNode caseNode : cases) {
-        caseNode.execute(frame, atom);
+        caseNode.executeAtom(frame, atom);
       }
-      fallback.execute(frame, atom);
+      fallback.executeAtom(frame, atom);
+      CompilerDirectives.transferToInterpreter();
+      throw new RuntimeException("Impossible behavior.");
+
+    } catch (BranchSelectedException e) {
+      // Note [Branch Selection Control Flow]
+      return e.getResult();
+
+    } catch (UnexpectedResultException e) {
+      typeErrorProfile.enter();
+      throw new TypeError("Expected an Atom.", this);
+    }
+  }
+
+  @ExplodeLoop
+  @Specialization
+  Object doFunction(VirtualFrame frame, Function function) {
+    try {
+      for (CaseNode caseNode : cases) {
+        caseNode.executeFunction(frame, function);
+      }
+      fallback.executeFunction(frame, function);
+      CompilerDirectives.transferToInterpreter();
+      throw new RuntimeException("Impossible behavior.");
+
+    } catch (BranchSelectedException e) {
+      // Note [Branch Selection Control Flow]
+      return e.getResult();
+
+    } catch (UnexpectedResultException e) {
+      typeErrorProfile.enter();
+      throw new TypeError("Expected an Atom.", this);
+    }
+  }
+
+  @ExplodeLoop
+  @Specialization
+  Object doNumber(VirtualFrame frame, long number) {
+    try {
+
+      for (CaseNode caseNode : cases) {
+        caseNode.executeNumber(frame, number);
+      }
+      fallback.executeNumber(frame, number);
       CompilerDirectives.transferToInterpreter();
       throw new RuntimeException("Impossible behavior.");
 

Interpreter/src/main/java/org/enso/interpreter/runtime/callable/UnresolvedSymbol.java

@@ -1,5 +1,6 @@
 package org.enso.interpreter.runtime.callable;
 
+import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.interop.TruffleObject;
 import org.enso.interpreter.runtime.callable.atom.AtomConstructor;
 import org.enso.interpreter.runtime.callable.function.Function;
@@ -27,7 +28,7 @@ public class UnresolvedSymbol implements TruffleObject {
    * <p>All names for dynamic symbols are interned, making it safe to compare symbol names using the
    * standard {@code ==} equality operator.
    *
-   * @return the name of this symbol.
+   * @return the name of this symbol
    */
   public String getName() {
     return name;
@@ -40,6 +41,26 @@ public class UnresolvedSymbol implements TruffleObject {
    * @return the resolved function definition, or null if not found
    */
   public Function resolveFor(AtomConstructor cons) {
-    return scope.lookupMethodDefinition(cons, name);
+    return scope.lookupMethodDefinitionForAtom(cons, name);
+  }
+
+  /**
+   * Resolves the symbol for a number.
+   *
+   * @return the resolved function definition, or null if not found
+   */
+  @CompilerDirectives.TruffleBoundary
+  public Function resolveForNumber() {
+    return scope.lookupMethodDefinitionForAny(name).orElse(null);
+  }
+
+  /**
+   * Resolves the symbol for a function.
+   *
+   * @return the resolved function definition, or null if not found
+   */
+  @CompilerDirectives.TruffleBoundary
+  public Function resolveForFunction() {
+    return scope.lookupMethodDefinitionForAny(name).orElse(null);
   }
 }

Interpreter/src/main/java/org/enso/interpreter/runtime/scope/ModuleScope.java

@@ -1,7 +1,6 @@
 package org.enso.interpreter.runtime.scope;
 
-import org.enso.interpreter.runtime.Builtins;
-import org.enso.interpreter.runtime.Module;
+import com.oracle.truffle.api.CompilerDirectives;
 import org.enso.interpreter.runtime.callable.atom.AtomConstructor;
 import org.enso.interpreter.runtime.callable.function.Function;
 
@@ -12,6 +11,7 @@ public class ModuleScope {
 
   private final Map<String, AtomConstructor> constructors = new HashMap<>();
   private final Map<AtomConstructor, Map<String, Function>> methods = new HashMap<>();
+  private final Map<String, Function> anyMethods = new HashMap<>();
   private final Set<ModuleScope> imports = new HashSet<>();
   private final Set<ModuleScope> transitiveImports = new HashSet<>();
 
@@ -57,38 +57,80 @@ public class ModuleScope {
   /**
    * Registers a method defined for a given type.
    *
-   * @param atom type the method was defined for.
-   * @param method method name.
-   * @param function the {@link Function} associated with this definition.
+   * @param atom type the method was defined for
+   * @param method method name
+   * @param function the {@link Function} associated with this definition
    */
   public void registerMethod(AtomConstructor atom, String method, Function function) {
     getMethodMapFor(atom).put(method, function);
   }
 
   /**
-   * Looks up the definition for a given type and method name. The resolution algorithm is first
-   * looking for methods defined at the constructor definition site (i.e. non-overloads), then looks
-   * for methods defined in this scope and finally tries to resolve the method in all transitive
-   * dependencies of this module.
+   * Registers a method for the {@code Any} type.
+   *
+   * @param methodName the name of the method to register
+   * @param function the {@link Function} associated with this definition
+   */
+  public void registerMethodForAny(String methodName, Function function) {
+    anyMethods.put(methodName, function);
+  }
+
+  /**
+   * Looks up the definition for a given type and method name.
+   *
+   * <p>The resolution algorithm is first looking for methods defined at the constructor definition
+   * site (i.e. non-overloads), then looks for methods defined in this scope and finally tries to
+   * resolve the method in all transitive dependencies of this module.
+   *
+   * <p>If the specific search fails, methods defined for any type are searched, first looking at
+   * locally defined methods and then all the transitive imports.
    *
    * @param atom type to lookup the method for.
    * @param name the method name.
    * @return the matching method definition or null if not found.
    */
-  public Function lookupMethodDefinition(AtomConstructor atom, String name) {
+  @CompilerDirectives.TruffleBoundary
+  public Function lookupMethodDefinitionForAtom(AtomConstructor atom, String name) {
+    return lookupSpecificMethodDefinitionForAtom(atom, name)
+        .orElseGet(() -> lookupMethodDefinitionForAny(name).orElse(null));
+  }
+
+  /**
+   * Looks up a method definition by-name, for methods defined on the type Any.
+   *
+   * <p>The resolution algorithm prefers methods defined locally over any other method. The
+   * definitions are imported into scope transitively.
+   *
+   * @param name the name of the method to look up
+   * @return {@code Optional.of(resultMethod)} if the method existed, {@code Optional.empty()}
+   *     otherwise
+   */
+  @CompilerDirectives.TruffleBoundary
+  public Optional<Function> lookupMethodDefinitionForAny(String name) {
+    Function definedHere = anyMethods.get(name);
+    if (definedHere != null) {
+      return Optional.of(definedHere);
+    }
+    return transitiveImports.stream()
+        .map(scope -> scope.getMethodsOfAny().get(name))
+        .filter(Objects::nonNull)
+        .findFirst();
+  }
+
+  private Optional<Function> lookupSpecificMethodDefinitionForAtom(
+      AtomConstructor atom, String name) {
     Function definedWithAtom = atom.getDefinitionScope().getMethodMapFor(atom).get(name);
     if (definedWithAtom != null) {
-      return definedWithAtom;
+      return Optional.of(definedWithAtom);
     }
     Function definedHere = getMethodMapFor(atom).get(name);
     if (definedHere != null) {
-      return definedHere;
+      return Optional.of(definedHere);
     }
     return transitiveImports.stream()
         .map(scope -> scope.getMethodMapFor(atom).get(name))
         .filter(Objects::nonNull)
-        .findFirst()
-        .orElse(null);
+        .findFirst();
   }
 
   /**
@@ -96,10 +138,14 @@ public class ModuleScope {
    *
    * @return a set of all the transitive dependencies of this module
    */
-  protected Set<ModuleScope> getTransitiveImports() {
+  private Set<ModuleScope> getTransitiveImports() {
     return transitiveImports;
   }
 
+  private Map<String, Function> getMethodsOfAny() {
+    return anyMethods;
+  }
+
   /**
    * Adds a dependency for this module.
    *

Interpreter/src/test/scala/org/enso/interpreter/test/semantic/InteropTest.scala

@@ -33,4 +33,15 @@ class InteropTest extends LanguageTest {
     val fun = eval(code)
     fun.call(1).call(2).call(3) shouldEqual 6
   }
+
+  "Interop library" should "work with oversaturated calls on unresolved methods returned from functions" in {
+    val code =
+      """
+        |Any.method = this
+        |
+        |{ |x| method }
+        |""".stripMargin
+    val fun = eval(code)
+    fun.call(1, 2) shouldEqual 2
+  }
 }

Interpreter/src/test/scala/org/enso/interpreter/test/semantic/MethodsTest.scala

@@ -42,6 +42,34 @@ class MethodsTest extends LanguageTest {
       """
         |@foo [7]
         |""".stripMargin
-    the[PolyglotException] thrownBy eval(code) should have message "Object 7 does not define method foo."
+    the[PolyglotException] thrownBy eval(code) should have message "Object Number does not define method foo."
+  }
+
+  "Methods defined on Any type" should "be callable for any type" in {
+    val code =
+      """
+        |type Foo;
+        |type Bar;
+        |type Baz;
+        |
+        |Any.method = { match this <
+        |  Foo ~ { 1 };
+        |  Bar ~ { 2 };
+        |  Baz ~ { 3 };
+        |  { 0 };
+        |>}
+        |
+        |@{
+        |  @println [@IO, @method [@Foo]];
+        |  @println [@IO, @method [@Bar]];
+        |  @println [@IO, @method [@Baz]];
+        |  @println [@IO, @method [@Unit]];
+        |  @println [@IO, @method [123]];
+        |  @println [@IO, @method [{|x| x }]];
+        |  0
+        |}
+        |""".stripMargin
+    eval(code)
+    consumeOut shouldEqual List("1", "2", "3", "0", "0", "0")
   }
 }