diff --git a/compiler/damlc/tests/daml-test-files/ActionFail.daml b/compiler/damlc/tests/daml-test-files/ActionFail.daml
index 1dadd4dccc..a307eeef61 100644
--- a/compiler/damlc/tests/daml-test-files/ActionFail.daml
+++ b/compiler/damlc/tests/daml-test-files/ActionFail.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use catOptionals
+-- @INFO range=9:21-9:38; Use catOptionals
 
 module ActionFail where
 
diff --git a/compiler/damlc/tests/daml-test-files/AmbiguousDataType.daml b/compiler/damlc/tests/daml-test-files/AmbiguousDataType.daml
index f482101292..d2514b5c5d 100644
--- a/compiler/damlc/tests/daml-test-files/AmbiguousDataType.daml
+++ b/compiler/damlc/tests/daml-test-files/AmbiguousDataType.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR range=9:1-9:17; Ambiguous data type declaration. Enums cannot have type arguments. Write data Foo x = Bar {} for a record or data Foo x = Bar () for a variant.
+-- @ERROR range=9:0-9:16; Ambiguous data type declaration. Enums cannot have type arguments. Write data Foo x = Bar {} for a record or data Foo x = Bar () for a variant.
 
 
 module AmbiguousDataType where
diff --git a/compiler/damlc/tests/daml-test-files/BadUTF8.daml b/compiler/damlc/tests/daml-test-files/BadUTF8.daml
index 8f8fbbbe05..b70e714454 100644
--- a/compiler/damlc/tests/daml-test-files/BadUTF8.daml
+++ b/compiler/damlc/tests/daml-test-files/BadUTF8.daml
@@ -1,4 +1,4 @@
--- @ERROR range=4:1-4:1; lexical error
+-- @ERROR range=4:0-4:0; lexical error
 
 
 £ -- pound symbol when saved as ASCII
diff --git a/compiler/damlc/tests/daml-test-files/ConstrainedRecursion.daml b/compiler/damlc/tests/daml-test-files/ConstrainedRecursion.daml
index 8c66ffc466..2b30b32428 100644
--- a/compiler/damlc/tests/daml-test-files/ConstrainedRecursion.daml
+++ b/compiler/damlc/tests/daml-test-files/ConstrainedRecursion.daml
@@ -1,9 +1,9 @@
 -- Copyright (c) 2020 The DAML Authors. All rights reserved.
 -- SPDX-License-Identifier: Apache-2.0
 --
--- @INFO range=12:1-13:21; Use foldl
--- @INFO range=16:1-17:17; Use foldl
--- @INFO range=20:1-21:17; Use foldl
+-- @INFO range=12:0-13:20; Use foldl
+-- @INFO range=16:0-17:16; Use foldl
+-- @INFO range=20:0-21:16; Use foldl
 
 module ConstrainedRecursion where
 
diff --git a/compiler/damlc/tests/daml-test-files/ConstraintBad.daml b/compiler/damlc/tests/daml-test-files/ConstraintBad.daml
index 28ba17c40d..c8d35fc196 100644
--- a/compiler/damlc/tests/daml-test-files/ConstraintBad.daml
+++ b/compiler/damlc/tests/daml-test-files/ConstraintBad.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR Constructors with type constraints must give explicit field names
+-- @ERROR range=11:13-11:28; Constructors with type constraints must give explicit field names
 
 {-# LANGUAGE ExistentialQuantification #-}
 
diff --git a/compiler/damlc/tests/daml-test-files/Cyclic.daml b/compiler/damlc/tests/daml-test-files/Cyclic.daml
index 9e92376527..b45494dd13 100644
--- a/compiler/damlc/tests/daml-test-files/Cyclic.daml
+++ b/compiler/damlc/tests/daml-test-files/Cyclic.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR Cyclic module dependency between Cyclic
+-- @ERROR range=8:7-8:13; Cyclic module dependency between Cyclic
 
 module Cyclic where
 
diff --git a/compiler/damlc/tests/daml-test-files/DesugarWarnings.daml b/compiler/damlc/tests/daml-test-files/DesugarWarnings.daml
index ab30bdaaac..9ef5da3c19 100644
--- a/compiler/damlc/tests/daml-test-files/DesugarWarnings.daml
+++ b/compiler/damlc/tests/daml-test-files/DesugarWarnings.daml
@@ -4,9 +4,9 @@
 {-# OPTIONS_GHC -Wincomplete-patterns -Woverlapping-patterns #-}
 -- Check that warnings from desugarer, like incomplete/overlapping pattern
 -- match warnings, show up when we turn them on.
--- @WARN range=14:21-15:14; Pattern match(es) are non-exhaustive
--- @WARN range=18:1-19:21; Pattern match(es) are non-exhaustive
--- @WARN range=24:3-24:14; Pattern match is redundant
+-- @WARN range=14:20-15:13; Pattern match(es) are non-exhaustive
+-- @WARN range=18:0-19:20; Pattern match(es) are non-exhaustive
+-- @WARN range=24:2-24:13; Pattern match is redundant
 
 module DesugarWarnings where
 
diff --git a/compiler/damlc/tests/daml-test-files/EmptyWith.daml b/compiler/damlc/tests/daml-test-files/EmptyWith.daml
index 36b0904e5f..66667acfaa 100644
--- a/compiler/damlc/tests/daml-test-files/EmptyWith.daml
+++ b/compiler/damlc/tests/daml-test-files/EmptyWith.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR range=18:12-19:1; Empty record update
+-- @ERROR range=18:11-19:0; Empty record update
 
 module EmptyWith where
 
diff --git a/compiler/damlc/tests/daml-test-files/EnumFromThenTo.daml b/compiler/damlc/tests/daml-test-files/EnumFromThenTo.daml
index bd6fb2b1b0..bbf797dfb8 100644
--- a/compiler/damlc/tests/daml-test-files/EnumFromThenTo.daml
+++ b/compiler/damlc/tests/daml-test-files/EnumFromThenTo.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR enumFromThenTo: from == then
+-- @ERROR range=9:0-9:4; enumFromThenTo: from == then
 
 module EnumFromThenTo where
 
diff --git a/compiler/damlc/tests/daml-test-files/ErrorsWithColons.daml b/compiler/damlc/tests/daml-test-files/ErrorsWithColons.daml
index 8686164375..483aee0d6a 100644
--- a/compiler/damlc/tests/daml-test-files/ErrorsWithColons.daml
+++ b/compiler/damlc/tests/daml-test-files/ErrorsWithColons.daml
@@ -1,9 +1,9 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO range=9:35-9:42; Use list literal
--- @ERROR range=9:35-9:42; In the expression: (1 :: [])
--- @ERROR range=11:13-11:14; In the expression: 1 : Text
+-- @INFO range=9:34-9:41; Use list literal
+-- @ERROR range=9:34-9:41; In the expression: (1 :: [])
+-- @ERROR range=11:12-11:13; In the expression: 1 : Text
 module ErrorsWithColons where
 
 badIf = if True then Some 1 else (1 :: [])
diff --git a/compiler/damlc/tests/daml-test-files/Existential.daml b/compiler/damlc/tests/daml-test-files/Existential.daml
index b2f6d435f7..e0678edd74 100644
--- a/compiler/damlc/tests/daml-test-files/Existential.daml
+++ b/compiler/damlc/tests/daml-test-files/Existential.daml
@@ -3,7 +3,7 @@
 
 {-# LANGUAGE ExistentialQuantification #-}
 
--- @ ERROR range=15:1-15:7; Pattern match with existential type.
+-- @ ERROR range=15:0-15:6; Pattern match with existential type.
 -- @ TODO Existential quantification
 
 
diff --git a/compiler/damlc/tests/daml-test-files/ExistentialSum.daml b/compiler/damlc/tests/daml-test-files/ExistentialSum.daml
index c4b28dc788..821af9bdb7 100644
--- a/compiler/damlc/tests/daml-test-files/ExistentialSum.daml
+++ b/compiler/damlc/tests/daml-test-files/ExistentialSum.daml
@@ -3,7 +3,7 @@
 
 {-# LANGUAGE ExistentialQuantification #-}
 
--- @ ERROR range=17:1-17:7; Pattern match with existential type.
+-- @ ERROR range=17:0-17:6; Pattern match with existential type.
 -- @ TODO Existential quantification
 
 
diff --git a/compiler/damlc/tests/daml-test-files/GenericTemplateError.daml b/compiler/damlc/tests/daml-test-files/GenericTemplateError.daml
index cb2bb15680..f28eeec006 100644
--- a/compiler/damlc/tests/daml-test-files/GenericTemplateError.daml
+++ b/compiler/damlc/tests/daml-test-files/GenericTemplateError.daml
@@ -1,6 +1,6 @@
 -- Copyright (c) 2020 Digital Asset (Switzerland) GmbH and/or its affiliates. All rights reserved.
 -- SPDX-License-Identifier: Apache-2.0
--- @ERROR range=11:24-11:34; Generic templates are no longer supported
+-- @ERROR range=11:23-11:33; Generic templates are no longer supported
 
 
 module GenericTemplateError where
diff --git a/compiler/damlc/tests/daml-test-files/GetPartyError.daml b/compiler/damlc/tests/daml-test-files/GetPartyError.daml
index abdbd70ad7..afd3e15942 100644
--- a/compiler/damlc/tests/daml-test-files/GetPartyError.daml
+++ b/compiler/damlc/tests/daml-test-files/GetPartyError.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR Invalid party name: #party
+-- @ ERROR range=8:0-8:4; Invalid party name: #party
 
 module GetPartyError where
 
diff --git a/compiler/damlc/tests/daml-test-files/HelloWorld.daml b/compiler/damlc/tests/daml-test-files/HelloWorld.daml
index 67f96d6f9f..7fe9bedaad 100644
--- a/compiler/damlc/tests/daml-test-files/HelloWorld.daml
+++ b/compiler/damlc/tests/daml-test-files/HelloWorld.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR Hello World!
+-- @ ERROR range=9:0-9:4; Hello World!
 
 
 module HelloWorld where
diff --git a/compiler/damlc/tests/daml-test-files/Import.daml b/compiler/damlc/tests/daml-test-files/Import.daml
index f7d618dc92..4bcf138403 100644
--- a/compiler/damlc/tests/daml-test-files/Import.daml
+++ b/compiler/damlc/tests/daml-test-files/Import.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR range=13:5-13:10; Couldn't match expected type ‘Good.T’
+-- @ ERROR range=13:4-13:9; Couldn't match expected type ‘Good.T’
 
 module Import where
 
diff --git a/compiler/damlc/tests/daml-test-files/IntBoundsUpper.daml b/compiler/damlc/tests/daml-test-files/IntBoundsUpper.daml
index a27c17b9d8..f34a50bf99 100644
--- a/compiler/damlc/tests/daml-test-files/IntBoundsUpper.daml
+++ b/compiler/damlc/tests/daml-test-files/IntBoundsUpper.daml
@@ -2,7 +2,7 @@
 -- All rights reserved.
 
 -- Test that overflowing integer literals are detected at compile time.
--- @ ERROR Int literal out of bounds
+-- @ ERROR range=10:0-10:6; Int literal out of bounds
 
 module IntBoundsUpper where
 
diff --git a/compiler/damlc/tests/daml-test-files/InternalImport.daml b/compiler/damlc/tests/daml-test-files/InternalImport.daml
index 630b3ed968..1f050b3629 100644
--- a/compiler/damlc/tests/daml-test-files/InternalImport.daml
+++ b/compiler/damlc/tests/daml-test-files/InternalImport.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR range=9:1-9:28; Import of internal module DA.Internal.Template is not allowed.
+-- @ERROR range=9:0-9:27; Import of internal module DA.Internal.Template is not allowed.
 
 
 module InternalImport where
diff --git a/compiler/damlc/tests/daml-test-files/Lazy.daml b/compiler/damlc/tests/daml-test-files/Lazy.daml
index ad7226e359..31bad3d718 100644
--- a/compiler/damlc/tests/daml-test-files/Lazy.daml
+++ b/compiler/damlc/tests/daml-test-files/Lazy.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR Hello World!
+-- @ ERROR range=9:0-9:4; Hello World!
 
 
 module Lazy where
diff --git a/compiler/damlc/tests/daml-test-files/List.daml b/compiler/damlc/tests/daml-test-files/List.daml
index 72308bf496..4a65205194 100644
--- a/compiler/damlc/tests/daml-test-files/List.daml
+++ b/compiler/damlc/tests/daml-test-files/List.daml
@@ -1,17 +1,17 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use null
--- @INFO Evaluate
--- @INFO Use sum
--- @INFO Use sum
--- @INFO Use sum
--- @INFO Use head
--- @INFO Use head
--- @INFO Use isNone
--- @INFO Use isNone
--- @INFO Use isNone
--- @INFO Use dedup
+-- @INFO range=36:16-36:29; Use section
+-- @INFO range=104:13-104:58; Use null
+-- @INFO range=118:16-118:31; Use dedup
+-- @INFO range=304:9-304:23; Evaluate
+-- @INFO range=319:37-319:47; Use sum
+-- @INFO range=320:42-320:52; Use sum
+-- @INFO range=321:28-321:38; Use sum
+-- @INFO range=324:2-324:22; Use head
+-- @INFO range=329:28-329:35; Use head
+-- @INFO range=336:11-336:33; Use isNone
+-- @INFO range=343:11-343:36; Use isNone
 
 module List where
 
diff --git a/compiler/damlc/tests/daml-test-files/Math.daml b/compiler/damlc/tests/daml-test-files/Math.daml
index 59ce228589..1bd1b1bbaf 100644
--- a/compiler/damlc/tests/daml-test-files/Math.daml
+++ b/compiler/damlc/tests/daml-test-files/Math.daml
@@ -1,8 +1,8 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use sqrt
--- @INFO Use sqrt
+-- @INFO range=47:21-47:31; Use sqrt
+-- @INFO range=57:14-57:24; Use sqrt
 
 
 module Math where
diff --git a/compiler/damlc/tests/daml-test-files/MaybeCompat.daml b/compiler/damlc/tests/daml-test-files/MaybeCompat.daml
index 2bff1e3ad0..b9834068c9 100644
--- a/compiler/damlc/tests/daml-test-files/MaybeCompat.daml
+++ b/compiler/damlc/tests/daml-test-files/MaybeCompat.daml
@@ -1,11 +1,11 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @WARN range=14:12-14:17; Maybe
--- @WARN range=17:12-17:17; maybe
--- @WARN range=17:29-17:36; Nothing
--- @WARN range=18:12-18:20; fromSome
--- @WARN range=18:22-18:26; Just
+-- @WARN range=14:11-14:16; Maybe
+-- @WARN range=17:11-17:16; maybe
+-- @WARN range=17:28-17:35; Nothing
+-- @WARN range=18:11-18:19; fromSome
+-- @WARN range=18:21-18:25; Just
 
 module MaybeCompat where
 import DA.Maybe
diff --git a/compiler/damlc/tests/daml-test-files/MissingFields.daml b/compiler/damlc/tests/daml-test-files/MissingFields.daml
index 4c6d4374e0..f0f65dd3b3 100644
--- a/compiler/damlc/tests/daml-test-files/MissingFields.daml
+++ b/compiler/damlc/tests/daml-test-files/MissingFields.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR range=10:10-10:22; does not have the required strict field(s): baz
+-- @ ERROR range=10:9-10:21; does not have the required strict field(s): baz
 
 module MissingFields where
 
diff --git a/compiler/damlc/tests/daml-test-files/ModuleName.daml b/compiler/damlc/tests/daml-test-files/ModuleName.daml
index e94405f4cd..c2bac057be 100644
--- a/compiler/damlc/tests/daml-test-files/ModuleName.daml
+++ b/compiler/damlc/tests/daml-test-files/ModuleName.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR Missing module name
+-- @ERROR range=1:0-100001:0; Missing module name
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/ModuleNameWarning.daml b/compiler/damlc/tests/daml-test-files/ModuleNameWarning.daml
index 86569a17f3..8159c92fe7 100644
--- a/compiler/damlc/tests/daml-test-files/ModuleNameWarning.daml
+++ b/compiler/damlc/tests/daml-test-files/ModuleNameWarning.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR Module names should always match file names
+-- @ ERROR range=7:7-7:25; Module names should always match file names
 
 
 module ModuleNameMismatch where
diff --git a/compiler/damlc/tests/daml-test-files/MultipleFields.daml b/compiler/damlc/tests/daml-test-files/MultipleFields.daml
index 465dcef602..a11e72ed8a 100644
--- a/compiler/damlc/tests/daml-test-files/MultipleFields.daml
+++ b/compiler/damlc/tests/daml-test-files/MultipleFields.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR range=9:12-9:23; Constructors with multiple fields must give explicit field names
+-- @ERROR range=9:11-9:22; Constructors with multiple fields must give explicit field names
 
 
 module MultipleFields where
diff --git a/compiler/damlc/tests/daml-test-files/NoCaseOfCase.daml b/compiler/damlc/tests/daml-test-files/NoCaseOfCase.daml
index b8f9f2e4b5..8bab0a281d 100644
--- a/compiler/damlc/tests/daml-test-files/NoCaseOfCase.daml
+++ b/compiler/damlc/tests/daml-test-files/NoCaseOfCase.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use if
+-- @INFO range=22:13-22:51; Use if
 
 
 module NoCaseOfCase where
diff --git a/compiler/damlc/tests/daml-test-files/NoControllerAsVar.daml b/compiler/damlc/tests/daml-test-files/NoControllerAsVar.daml
index e49b759d0f..dfca013fa3 100644
--- a/compiler/damlc/tests/daml-test-files/NoControllerAsVar.daml
+++ b/compiler/damlc/tests/daml-test-files/NoControllerAsVar.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR parse error on input ‘controller’
+-- @ ERROR range=15:0-15:10; parse error on input ‘controller’
 
 
 module NoControllerAsVar where
diff --git a/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB.daml b/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB.daml
index 3e5ebff370..a7e3d1ae6c 100644
--- a/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB.daml
+++ b/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB.daml
@@ -5,7 +5,7 @@
 -- `NumericScale` constraint.
 --
 -- @SINCE-LF 1.7
--- @ERROR No instance for (NumericScale 38)
+-- @ERROR range=16:11-16:18; No instance for (NumericScale 38)
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB2.daml b/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB2.daml
index 9bd5472b49..6b68a4561d 100644
--- a/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB2.daml
+++ b/compiler/damlc/tests/daml-test-files/NumericLitMonoScaleOOB2.daml
@@ -6,7 +6,7 @@
 -- conversion error even if we try to be clever.
 --
 -- @SINCE-LF 1.7
--- @ERROR type-level natural outside of supported range [0, 37]
+-- @ERROR range=17:0-17:8; type-level natural outside of supported range [0, 37]
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/NumericLitPoly.daml b/compiler/damlc/tests/daml-test-files/NumericLitPoly.daml
index 5cbd90513c..755037d359 100644
--- a/compiler/damlc/tests/daml-test-files/NumericLitPoly.daml
+++ b/compiler/damlc/tests/daml-test-files/NumericLitPoly.daml
@@ -6,7 +6,7 @@
 -- conversion error even if we try to be clever.
 --
 -- @SINCE-LF 1.7
--- @ERROR Polymorphic numeric literal. Specify a fixed scale by giving the type, e.g. (2.71828 : Numeric 10)
+-- @ERROR range=19:0-19:7; Polymorphic numeric literal. Specify a fixed scale by giving the type, e.g. (2.71828 : Numeric 10)
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/PartyCompare.daml b/compiler/damlc/tests/daml-test-files/PartyCompare.daml
index 42d829e310..4aca26da79 100644
--- a/compiler/damlc/tests/daml-test-files/PartyCompare.daml
+++ b/compiler/damlc/tests/daml-test-files/PartyCompare.daml
@@ -1,12 +1,12 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use >=
--- @INFO Use >=
--- @INFO Use >
--- @INFO Use <
--- @INFO Use <=
--- @INFO Use <=
+-- @INFO range=18:11-18:30; Use >=
+-- @INFO range=19:11-19:28; Use >=
+-- @INFO range=22:11-22:29; Use >
+-- @INFO range=25:11-25:29; Use <
+-- @INFO range=27:11-27:28; Use <=
+-- @INFO range=28:11-28:26; Use <=
 
 
 module PartyCompare where
diff --git a/compiler/damlc/tests/daml-test-files/PatError.daml b/compiler/damlc/tests/daml-test-files/PatError.daml
index 91ecf312ae..d842e92391 100644
--- a/compiler/damlc/tests/daml-test-files/PatError.daml
+++ b/compiler/damlc/tests/daml-test-files/PatError.daml
@@ -4,7 +4,7 @@
 {-# OPTIONS_GHC -Wno-incomplete-patterns #-}
 -- Make sure the error message is useful when the interpreter is face with
 -- an incomplete pattern match.
--- @ERROR PatError.daml:(11,7)-(12,14): Non-exhaustive patterns in case
+-- @ERROR range=14:0-14:4; Non-exhaustive patterns in case
 
 module PatError where
 
diff --git a/compiler/damlc/tests/daml-test-files/Phantom.daml b/compiler/damlc/tests/daml-test-files/Phantom.daml
index 4d3eb29f98..235b9ff8db 100644
--- a/compiler/damlc/tests/daml-test-files/Phantom.daml
+++ b/compiler/damlc/tests/daml-test-files/Phantom.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Replace case with optional
+-- @INFO range=16:19-18:18; Replace case with optional
 
 
 module Phantom where
diff --git a/compiler/damlc/tests/daml-test-files/PolymorphicTest.daml b/compiler/damlc/tests/daml-test-files/PolymorphicTest.daml
index a6573c9352..a19000cdb5 100644
--- a/compiler/damlc/tests/daml-test-files/PolymorphicTest.daml
+++ b/compiler/damlc/tests/daml-test-files/PolymorphicTest.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR Aborted: boom
+-- @ERROR range=9:0-9:4; Aborted: boom
 
 module PolymorphicTest where
 
diff --git a/compiler/damlc/tests/daml-test-files/Precondition.daml b/compiler/damlc/tests/daml-test-files/Precondition.daml
index 77ffdd76e1..979d71ab7a 100644
--- a/compiler/damlc/tests/daml-test-files/Precondition.daml
+++ b/compiler/damlc/tests/daml-test-files/Precondition.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR Template pre-condition violated
+-- @ERROR range=22:0-22:4; Template pre-condition violated
 
 module Precondition where
 
diff --git a/compiler/damlc/tests/daml-test-files/PreludeTest.daml b/compiler/damlc/tests/daml-test-files/PreludeTest.daml
index 2400778f34..07f386da5d 100644
--- a/compiler/damlc/tests/daml-test-files/PreludeTest.daml
+++ b/compiler/damlc/tests/daml-test-files/PreludeTest.daml
@@ -1,39 +1,39 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use uncurry
--- @INFO Redundant identity
--- @INFO Redundant identity
--- @INFO Redundant identity
--- @INFO Evaluate
--- @INFO Use elem
--- @INFO Use elem
--- @INFO Use elem
--- @INFO Redundant if
--- @INFO Redundant if
--- @INFO Use ||
--- @INFO Use ||
--- @INFO Use ||
--- @INFO Use &&
--- @INFO Use &&
--- @INFO Use &&
--- @INFO Use isNone
--- @INFO Use $>
--- @INFO Evaluate
--- @INFO Evaluate
--- @INFO Use ++
--- @INFO Redundant flip
--- @INFO Redundant flip
--- @INFO Evaluate
--- @INFO Take on a non-positive
--- @INFO Drop on a non-positive
--- @INFO Use zip
--- @INFO Use zip
--- @INFO Use zip3
--- @INFO Use zip3
--- @INFO Evaluate
--- @INFO Evaluate
--- @INFO Evaluate
+-- @INFO range=51:26-51:42; Use uncurry
+-- @INFO range=65:8-65:18; Redundant identity
+-- @INFO range=66:12-66:26; Redundant identity
+-- @INFO range=67:22-67:60; Redundant identity
+-- @INFO range=89:8-89:17; Evaluate
+-- @INFO range=93:12-93:21; Use elem
+-- @INFO range=94:12-94:21; Use elem
+-- @INFO range=95:10-95:19; Use elem
+-- @INFO range=99:22-99:59; Redundant if
+-- @INFO range=108:23-108:61; Redundant if
+-- @INFO range=111:12-111:36; Use ||
+-- @INFO range=113:11-113:34; Use ||
+-- @INFO range=114:11-114:26; Use ||
+-- @INFO range=117:12-117:37; Use &&
+-- @INFO range=119:12-119:36; Use &&
+-- @INFO range=120:11-120:27; Use &&
+-- @INFO range=155:11-155:35; Use isNone
+-- @INFO range=155:20-155:34; Use $>
+-- @INFO range=161:9-161:55; Evaluate
+-- @INFO range=162:9-162:58; Evaluate
+-- @INFO range=175:16-175:35; Use ++
+-- @INFO range=179:8-179:21; Redundant flip
+-- @INFO range=180:14-180:37; Redundant flip
+-- @INFO range=206:12-206:52; Evaluate
+-- @INFO range=218:9-218:28; Take on a non-positive
+-- @INFO range=224:9-224:28; Drop on a non-positive
+-- @INFO range=290:27-290:38; Use zip
+-- @INFO range=291:37-291:48; Use zip
+-- @INFO range=295:37-295:50; Use zip3
+-- @INFO range=296:52-296:65; Use zip3
+-- @INFO range=308:8-308:20; Evaluate
+-- @INFO range=311:10-311:22; Evaluate
+-- @INFO range=315:12-315:19; Evaluate
 
 
 module PreludeTest where
diff --git a/compiler/damlc/tests/daml-test-files/RationalLowerBoundError.daml b/compiler/damlc/tests/daml-test-files/RationalLowerBoundError.daml
index cce642c125..d5b15a1eab 100644
--- a/compiler/damlc/tests/daml-test-files/RationalLowerBoundError.daml
+++ b/compiler/damlc/tests/daml-test-files/RationalLowerBoundError.daml
@@ -2,7 +2,7 @@
 -- All rights reserved.
 
 -- Test that rational negative literals bigger or equal -10^38 + 1 fail.
--- @ERROR Rational is out of bounds
+-- @ERROR range=13:0-13:1; Rational is out of bounds
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/RationalPrecisionUpperBoundError.daml b/compiler/damlc/tests/daml-test-files/RationalPrecisionUpperBoundError.daml
index ac0949b7c7..1f93af60fa 100644
--- a/compiler/damlc/tests/daml-test-files/RationalPrecisionUpperBoundError.daml
+++ b/compiler/damlc/tests/daml-test-files/RationalPrecisionUpperBoundError.daml
@@ -2,7 +2,7 @@
 -- All rights reserved.
 
 -- Test that rational literals with precision higher then e^-10 fail.
--- @ERROR Rational is out of bounds
+-- @ERROR range=12:0-12:1; Rational is out of bounds
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/RationalUpperBoundError.daml b/compiler/damlc/tests/daml-test-files/RationalUpperBoundError.daml
index 8104dad00f..b76d98f7e6 100644
--- a/compiler/damlc/tests/daml-test-files/RationalUpperBoundError.daml
+++ b/compiler/damlc/tests/daml-test-files/RationalUpperBoundError.daml
@@ -2,7 +2,7 @@
 -- All rights reserved.
 
 -- Test that rational positive literals fail when bigger than 10^38 -1 after multiplying with 10^10.
--- @ERROR Rational is out of bounds
+-- @ERROR range=13:0-13:1; Rational is out of bounds
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/RecordConstructorCheck.daml b/compiler/damlc/tests/daml-test-files/RecordConstructorCheck.daml
index c05b75c568..31f8e26b00 100644
--- a/compiler/damlc/tests/daml-test-files/RecordConstructorCheck.daml
+++ b/compiler/damlc/tests/daml-test-files/RecordConstructorCheck.daml
@@ -1,9 +1,9 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR Record type X has constructor Y with different name. Possible solution: Change the constructor name to X
+-- @ERROR range=10:0-10:13; Record type X has constructor Y with different name. Possible solution: Change the constructor name to X
 
--- @ERROR Record type A has constructor B with different name. Possible solution: Change the constructor name to A
+-- @ERROR range=12:0-12:26; Record type A has constructor B with different name. Possible solution: Change the constructor name to A
 
 module RecordConstructorCheck where
 
diff --git a/compiler/damlc/tests/daml-test-files/RecordUpdate.daml b/compiler/damlc/tests/daml-test-files/RecordUpdate.daml
index f3eb406dac..12752ccf2f 100644
--- a/compiler/damlc/tests/daml-test-files/RecordUpdate.daml
+++ b/compiler/damlc/tests/daml-test-files/RecordUpdate.daml
@@ -1,8 +1,8 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Evaluate
--- @INFO Use const
+-- @INFO range=43:17-43:41; Evaluate
+-- @INFO range=43:24-43:40; Use const
 
 
 
diff --git a/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden1.daml b/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden1.daml
index d24eb7f0c5..258c2777ea 100644
--- a/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden1.daml
+++ b/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden1.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR No instance for (DA.Internal.Record.HasField "microseconds" RelTime Int)
+-- @ ERROR range=11:9-11:24; No instance for (DA.Internal.Record.HasField "microseconds" RelTime Int)
 
 module RelTimeDetailsHidden1 where
 
diff --git a/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden2.daml b/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden2.daml
index 6e9af8e2a6..f24427ad5f 100644
--- a/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden2.daml
+++ b/compiler/damlc/tests/daml-test-files/RelTimeDetailsHidden2.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR Not in scope: data constructor ‘RelTime’
+-- @ ERROR range=11:5-11:12; Not in scope: data constructor ‘RelTime’
 
 module RelTimeDetailsHidden2 where
 
diff --git a/compiler/damlc/tests/daml-test-files/RightOfUse.daml b/compiler/damlc/tests/daml-test-files/RightOfUse.daml
index e22c110b5f..0b51ec0d7e 100644
--- a/compiler/damlc/tests/daml-test-files/RightOfUse.daml
+++ b/compiler/damlc/tests/daml-test-files/RightOfUse.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ERROR Scenario execution failed on commit at RightOfUse:56:5:
+-- @ERROR range=44:0-44:7; Scenario execution failed on commit at RightOfUse:56:5:
 
 
 module RightOfUse where
diff --git a/compiler/damlc/tests/daml-test-files/Set.daml b/compiler/damlc/tests/daml-test-files/Set.daml
index 655ae04dea..d029d28df2 100644
--- a/compiler/damlc/tests/daml-test-files/Set.daml
+++ b/compiler/damlc/tests/daml-test-files/Set.daml
@@ -1,10 +1,10 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use infix
--- @INFO Use infix
--- @INFO Use infix
--- @INFO Use infix
+-- @INFO range=57:30-57:77; Use infix
+-- @INFO range=58:21-58:52; Use infix
+-- @INFO range=59:24-59:58; Use infix
+-- @INFO range=60:17-60:54; Use infix
 
 -- @SINCE-LF 1.3
 
diff --git a/compiler/damlc/tests/daml-test-files/ShortCircuit.daml b/compiler/damlc/tests/daml-test-files/ShortCircuit.daml
index 8e721953c2..42950638eb 100644
--- a/compiler/damlc/tests/daml-test-files/ShortCircuit.daml
+++ b/compiler/damlc/tests/daml-test-files/ShortCircuit.daml
@@ -1,10 +1,10 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Redundant ==
--- @INFO Evaluate
--- @INFO Redundant ==
--- @INFO Evaluate
+-- @INFO range=15:11-15:41; Redundant ==
+-- @INFO range=15:12-15:32; Evaluate
+-- @INFO range=16:11-16:43; Redundant ==
+-- @INFO range=16:12-16:33; Evaluate
 
 
 module ShortCircuit where
diff --git a/compiler/damlc/tests/daml-test-files/Text.daml b/compiler/damlc/tests/daml-test-files/Text.daml
index 08b6976b3c..22fc36ca37 100644
--- a/compiler/damlc/tests/daml-test-files/Text.daml
+++ b/compiler/damlc/tests/daml-test-files/Text.daml
@@ -1,13 +1,13 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Evaluate
--- @INFO Evaluate
--- @INFO Use null
--- @INFO Use null
--- @INFO Use null
--- @INFO Use isNone
--- @INFO Use isNone
+-- @INFO range=41:9-41:17; Evaluate
+-- @INFO range=55:2-55:12; Evaluate
+-- @INFO range=61:13-61:46; Use null
+-- @INFO range=69:13-69:46; Use null
+-- @INFO range=70:13-70:46; Use null
+-- @INFO range=92:13-92:47; Use isNone
+-- @INFO range=97:13-97:47; Use isNone
 
 
 module Text where
diff --git a/compiler/damlc/tests/daml-test-files/Trace.daml b/compiler/damlc/tests/daml-test-files/Trace.daml
index 68d4c59ec4..bbecd8c9bd 100644
--- a/compiler/damlc/tests/daml-test-files/Trace.daml
+++ b/compiler/damlc/tests/daml-test-files/Trace.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @INFO Use <$>
+-- @INFO range=11:11-11:42; Use <$>
 
 
 module Trace where
diff --git a/compiler/damlc/tests/daml-test-files/TypeFamily.daml b/compiler/damlc/tests/daml-test-files/TypeFamily.daml
index 89a21f1e56..13a7b04c96 100644
--- a/compiler/damlc/tests/daml-test-files/TypeFamily.daml
+++ b/compiler/damlc/tests/daml-test-files/TypeFamily.daml
@@ -3,7 +3,7 @@
 
 {-# LANGUAGE TypeFamilies #-}
 
--- @ERROR range=11:1-11:16; Data definition, of type type family.
+-- @ERROR range=11:0-11:15; Data definition, of type type family.
 
 
 module TypeFamily where
diff --git a/compiler/damlc/tests/daml-test-files/Unicode.daml b/compiler/damlc/tests/daml-test-files/Unicode.daml
index 021de8cdb3..383c1712c0 100644
--- a/compiler/damlc/tests/daml-test-files/Unicode.daml
+++ b/compiler/damlc/tests/daml-test-files/Unicode.daml
@@ -1,7 +1,7 @@
 -- Copyright (c) 2020, Digital Asset (Switzerland) GmbH and/or its affiliates.
 -- All rights reserved.
 
--- @ ERROR ⛄ ¯\_(ツ)_/¯
+-- @ERROR range=9:0-9:4; ⛄ ¯\_(ツ)_/¯
 
 
 module Unicode where
diff --git a/compiler/damlc/tests/daml-test-files/Unserializable.daml b/compiler/damlc/tests/daml-test-files/Unserializable.daml
index f6ede441c0..50d4143fa1 100644
--- a/compiler/damlc/tests/daml-test-files/Unserializable.daml
+++ b/compiler/damlc/tests/daml-test-files/Unserializable.daml
@@ -5,7 +5,7 @@
 -- We use the template typeclass and instances directly as otherwise the error
 -- is caught prior due to missing Eq and Show instances.
 
--- @ERROR expected serializable type
+-- @ERROR range=1:0-100001:0; expected serializable type
 
 module Unserializable where
 
diff --git a/compiler/damlc/tests/src/DA/Test/DamlcIntegration.hs b/compiler/damlc/tests/src/DA/Test/DamlcIntegration.hs
index ce09f257bd..57875aa70d 100644
--- a/compiler/damlc/tests/src/DA/Test/DamlcIntegration.hs
+++ b/compiler/damlc/tests/src/DA/Test/DamlcIntegration.hs
@@ -318,9 +318,40 @@ parseRange :: String -> Range
 parseRange s =
   case traverse readMaybe (wordsBy (`elem` (":-" :: String)) s) of
     Just [rowStart, colStart, rowEnd, colEnd] ->
-        Range
-            (Position (rowStart - 1) (colStart - 1))
-            (Position (rowEnd - 1) (colEnd - 1))
+      -- When specifying ranges:
+      --  * lines are 1-based
+      --  * columns are 0-based
+      --  * the column span is open, that is, the end column is "one
+      --    past the end" of the span.
+      --
+      -- Positions in these ranges are matched against LSP coordinates
+      -- which are 0-based in both line and column and also open. Error
+      -- messages are formatted by GHC and are 1-based in line, 0-based
+      -- in column and closed (so add one to column start, one to
+      -- column end to make them 1-based, then subtract one from column
+      -- end to convert to closed!)
+      --
+      -- 'showDiagnostics' reports ranges such that lines are 1-based,
+      -- columns are 0-based and open.
+      --
+      -- Example:
+      --   If @INFO 'range=8:13-8:47':
+      --   then the actual (LSP) range is
+      --      { _start = Position {_line = 7, _character = 13}
+      --      ,   _end = Position {_line = 7, _character = 47}}
+      --   and 'showDiagnostics' reports:
+      --     Hidden:   no
+      --     Range:    8:13-8:47
+      --     Source:   linter
+      --     Severity: DsInfo
+      --     Message:  RangeTest.daml:8:14-47: Some error message.
+      --
+      -- TL;DR: To mark a diagnostic as "expected" paste the range as it
+      -- appears in 'showDiagnostics' e.g. '@INFO range=8:13-8:47; Some
+      -- error message'.
+      Range
+        (Position (rowStart - 1) colStart)
+        (Position (rowEnd - 1) colEnd)
     _ -> error $ "Failed to parse range, got " ++ s
 
 mainProj :: TestArguments -> IdeState -> FilePath -> (String -> IO ()) -> NormalizedFilePath -> IO LF.Package