Improve handling of line directives

src/Compiler/SyntaxTree/ParseHelpers.fs

@@ -43,7 +43,11 @@ let posOfLexPosition (p: Position) = mkPos p.Line p.Column
 
 /// Get an F# compiler range from a lexer range
 let mkSynRange (p1: Position) (p2: Position) =
-    mkFileIndexRange p1.FileIndex (posOfLexPosition p1) (posOfLexPosition p2)
+    if p1.FileIndex = p2.FileIndex then
+        mkFileIndexRange p1.FileIndex (posOfLexPosition p1) (posOfLexPosition p2)
+    else
+        // This means we had a #line directive in the middle of this syntax element.
+        mkFileIndexRange p1.FileIndex (posOfLexPosition p1) (posOfLexPosition (p1.ShiftColumnBy 1))
 
 type LexBuffer<'Char> with
 

tests/FSharp.Compiler.ComponentTests/CompilerDirectives/Line.fs

@@ -0,0 +1,66 @@
+namespace CompilerDirectives
+
+open Microsoft.FSharp.Control
+open Xunit
+open FSharp.Test.Compiler
+open FSharp.Compiler.CodeAnalysis
+open FSharp.Compiler.Text
+open FSharp.Compiler.Syntax
+
+module Line =
+
+    let checker = FSharpChecker.Create()
+
+    let parse (source: string) =
+        let langVersion = "preview"
+        let sourceFileName = __SOURCE_FILE__
+        let parsingOptions =
+            { FSharpParsingOptions.Default with
+                SourceFiles = [| sourceFileName |]
+                LangVersionText = langVersion
+                ApplyLineDirectives = true
+                }
+        checker.ParseFile(sourceFileName, SourceText.ofString source, parsingOptions) |> Async.RunSynchronously
+
+
+    [<Literal>]
+    let private case1 = """module A
+#line 1 "xyz.fs"
+(
+printfn ""
+)
+    """
+
+    [<Literal>]
+    let private case2 = """module A
+(
+#line 1 "xyz.fs"
+printfn ""
+)
+    """
+
+    [<Literal>]
+    let private case3 = """module A
+(
+#line 1 "xyz.fs"
+)
+    """
+
+    [<Theory>]
+    [<InlineData(1, case1, "xyz.fs:(1,0--3,1)")>]
+    [<InlineData(2, case2, "Line.fs:(2,0--2,1)")>]
+    [<InlineData(3, case3, "Line.fs:(2,0--2,1)")>]
+    let ``check expr range interacting with line directive`` (case, source, expectedRange) =
+        let parseResults = parse source
+        if parseResults.ParseHadErrors then failwith "unexpected: parse error"
+        let exprRange =
+            match parseResults.ParseTree with
+            | ParsedInput.ImplFile(ParsedImplFileInput(contents = contents)) ->
+                let (SynModuleOrNamespace(decls = decls)) = List.exactlyOne contents
+                match List.exactlyOne decls with
+                | SynModuleDecl.Expr(_, range) -> $"{range.FileName}:{range}"
+                | _ -> failwith $"unexpected: not an expr"
+            | ParsedInput.SigFile _ -> failwith "unexpected: sig file"
+        if exprRange <> expectedRange then
+            failwith $"case{case}: expected: {expectedRange}, found {exprRange}"
+

tests/FSharp.Compiler.ComponentTests/ErrorMessages/Directives.fs → tests/FSharp.Compiler.ComponentTests/CompilerDirectives/NonStringArgs.fs

@@ -1,10 +1,10 @@
 // Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
-namespace ErrorMessages
+namespace CompilerDirectives
 
 open Xunit
 open FSharp.Test.Compiler
 
-module HashDirectives =
+module NonStringArgs =
 
     [<InlineData("8.0")>]
     [<InlineData("9.0")>]

tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj

@@ -31,6 +31,8 @@
     <Compile Include="..\service\FsUnit.fs">
       <Link>FsUnit.fs</Link>
     </Compile>
+    <Compile Include="CompilerDirectives\Line.fs" />
+    <Compile Include="CompilerDirectives\NonStringArgs.fs" />
     <Compile Include="Conformance\BasicGrammarElements\AccessibilityAnnotations\Basic\Basic.fs" />
     <Compile Include="Conformance\BasicGrammarElements\AccessibilityAnnotations\OnOverridesAndIFaceImpl\OnOverridesAndIFaceImpl.fs" />
     <Compile Include="Conformance\BasicGrammarElements\AccessibilityAnnotations\OnTypeMembers\OnTypeMembers.fs" />
@@ -177,9 +179,9 @@
     <Compile Include="EmittedIL\TestFunctions\TestFunctions.fs" />
     <Compile Include="EmittedIL\Tuples\Tuples.fs" />
     <Compile Include="EmittedIL\Nullness\NullnessMetadata.fs" />
+    <Compile Include="EmittedIL\FixedBindings\FixedBindings.fs" />
     <Compile Include="ErrorMessages\TypedInterpolatedStringsTests.fs" />
     <!--<Compile Include="EmittedIL\StructDefensiveCopy\StructDefensiveCopy.fs" />-->
-    <Compile Include="EmittedIL\FixedBindings\FixedBindings.fs" />
     <Compile Include="ErrorMessages\UnsupportedAttributes.fs" />
     <Compile Include="ErrorMessages\TailCallAttribute.fs" />
     <Compile Include="ErrorMessages\IndexingSyntax.fs" />
@@ -196,7 +198,6 @@
     <Compile Include="ErrorMessages\MissingExpressionTests.fs" />
     <Compile Include="ErrorMessages\ModuleTests.fs" />
     <Compile Include="ErrorMessages\NameResolutionTests.fs" />
-    <Compile Include="ErrorMessages\Directives.fs" />
     <Compile Include="ErrorMessages\SuggestionsTests.fs" />
     <Compile Include="ErrorMessages\TypeMismatchTests.fs" />
     <Compile Include="ErrorMessages\UnitGenericAbstactType.fs" />