Add extern keyword to SynBindingTrivia.

src/Compiler/SyntaxTree/ParseHelpers.fs

@@ -468,6 +468,7 @@ let mkSynMemberDefnGetSet
             {
                 LetKeyword = None
                 EqualsRange = mEquals
+                ExternKeyword = None
             }
 
         let binding =
@@ -542,6 +543,7 @@ let mkSynMemberDefnGetSet
                 {
                     LetKeyword = None
                     EqualsRange = mEquals
+                    ExternKeyword = None
                 }
 
             let binding =
@@ -629,6 +631,7 @@ let mkSynMemberDefnGetSet
                     {
                         LetKeyword = None
                         EqualsRange = mEquals
+                        ExternKeyword = None
                     }
 
                 let bindingOuter =

src/Compiler/SyntaxTree/SyntaxTrivia.fs

@@ -159,12 +159,14 @@ type SynTypeDefnSigTrivia =
 type SynBindingTrivia =
     {
         LetKeyword: range option
+        ExternKeyword: range option
         EqualsRange: range option
     }
 
     static member Zero: SynBindingTrivia =
         {
             LetKeyword = None
+            ExternKeyword = None
             EqualsRange = None
         }
 

src/Compiler/SyntaxTree/SyntaxTrivia.fsi

@@ -246,6 +246,9 @@ type SynBindingTrivia =
         /// The syntax range of the `let` keyword.
         LetKeyword: range option
 
+        /// The syntax range of the `extern` keyword.
+        ExternKeyword: range option
+
         /// The syntax range of the `=` token.
         EqualsRange: range option
     }

src/Compiler/pars.fsy

@@ -1868,7 +1868,7 @@ memberCore:
             let xmlDoc = grabXmlDocAtRangeStart(parseState, attrs, rangeStart)
             let memberFlags = Some (memFlagsBuilder SynMemberKind.Member)
             let mWholeBindLhs = (mBindLhs, attrs) ||> unionRangeWithListBy (fun (a: SynAttributeList) -> a.Range)
-            let trivia: SynBindingTrivia = { LetKeyword = None; EqualsRange = Some mEquals }
+            let trivia: SynBindingTrivia = { LetKeyword = None; EqualsRange = Some mEquals; ExternKeyword = None }
             let binding = mkSynBinding (xmlDoc, bindingPat) (vis, $1, false, mWholeBindLhs, DebugPointAtBinding.NoneAtInvisible, optReturnType, $5, mRhs, [], attrs, memberFlags, trivia)
             let memberRange = unionRanges rangeStart mRhs |> unionRangeWithXmlDoc xmlDoc
             [ SynMemberDefn.Member (binding, memberRange) ]) }
@@ -1985,7 +1985,7 @@ classDefnMember:
         let declPat = SynPat.LongIdent (SynLongIdent([mkSynId (rhs parseState 3) "new"], [], [None]), None, Some noInferredTypars, SynArgPats.Pats [$4], vis, rhs parseState 3)
         // Check that 'SynPatForConstructorDecl' matches this correctly
         assert (match declPat with SynPatForConstructorDecl _ -> true | _ -> false)
-        let synBindingTrivia: SynBindingTrivia = { LetKeyword = None; EqualsRange = Some mEquals }
+        let synBindingTrivia: SynBindingTrivia = { LetKeyword = None; EqualsRange = Some mEquals; ExternKeyword = None }
         [ SynMemberDefn.Member(SynBinding (None, SynBindingKind.Normal, false, false, $1, xmlDoc, valSynData, declPat, None, expr, mWholeBindLhs, DebugPointAtBinding.NoneAtInvisible, synBindingTrivia), m) ] }
 
   | opt_attributes opt_declVisibility STATIC typeKeyword tyconDefn 
@@ -2743,7 +2743,8 @@ hardwhiteDefnBindingsTerminator:
 /* An 'extern' DllImport function definition in C-style syntax */
 cPrototype: 
   | EXTERN cRetType opt_access ident opt_HIGH_PRECEDENCE_APP LPAREN externArgs rparen 
-      { let rty, vis, nm, args  = $2, $3, $4, $7
+      { let mExtern = rhs parseState 1 
+        let rty, vis, nm, args  = $2, $3, $4, $7
         let nmm = rhs parseState 3 
         let argsm = rhs parseState 6 
         let mBindLhs = lhs parseState
@@ -2760,10 +2761,11 @@ cPrototype:
             let bindingPat = SynPat.LongIdent (SynLongIdent([nm], [], [None]), None, Some noInferredTypars, SynArgPats.Pats [SynPat.Tuple(false, args, argsm)], vis, nmm)
             let mWholeBindLhs = (mBindLhs, attrs) ||> unionRangeWithListBy (fun (a: SynAttributeList) -> a.Range)
             let xmlDoc = grabXmlDoc(parseState, attrs, 1)
+            let trivia = { LetKeyword = None; ExternKeyword = Some mExtern; EqualsRange = None }
             let binding =
                 mkSynBinding 
                     (xmlDoc, bindingPat) 
-                    (vis, false, false, mWholeBindLhs, DebugPointAtBinding.NoneAtInvisible, Some rty, rhsExpr, mRhs, [], attrs, None, SynBindingTrivia.Zero)
+                    (vis, false, false, mWholeBindLhs, DebugPointAtBinding.NoneAtInvisible, Some rty, rhsExpr, mRhs, [], attrs, None, trivia)
             [], [binding]) }
 
 /* A list of arguments in an 'extern' DllImport function definition */
@@ -2882,7 +2884,7 @@ localBinding:
             let mWhole = (unionRanges mLetKwd mRhs, attrs) ||> unionRangeWithListBy (fun (a: SynAttributeList) -> a.Range)
             let spBind = if IsDebugPointBinding bindingPat expr then DebugPointAtBinding.Yes mWhole else DebugPointAtBinding.NoneAtLet
             let mWholeBindLhs = (mBindLhs, attrs) ||> unionRangeWithListBy (fun (a: SynAttributeList) -> a.Range)
-            let trivia: SynBindingTrivia = { LetKeyword = Some mLetKwd; EqualsRange = Some mEquals }
+            let trivia: SynBindingTrivia = { LetKeyword = Some mLetKwd; EqualsRange = Some mEquals; ExternKeyword = None }
             mkSynBinding (xmlDoc, bindingPat) (vis, $1, $2, mWholeBindLhs, spBind, optReturnType, expr, mRhs, opts, attrs, None, trivia))
         localBindingRange, localBindingBuilder }
 
@@ -2897,7 +2899,7 @@ localBinding:
             let zeroWidthAtEnd = mEquals.EndRange
             let rhsExpr = arbExpr("localBinding1", zeroWidthAtEnd)
             let spBind = if IsDebugPointBinding bindingPat rhsExpr then DebugPointAtBinding.Yes mWhole else DebugPointAtBinding.NoneAtLet
-            let trivia: SynBindingTrivia = { LetKeyword = Some mLetKwd; EqualsRange = Some mEquals }
+            let trivia: SynBindingTrivia = { LetKeyword = Some mLetKwd; EqualsRange = Some mEquals; ExternKeyword = None }
             mkSynBinding (xmlDoc, bindingPat) (vis, $1, $2, mBindLhs, spBind, optReturnType, rhsExpr, mRhs, [], attrs, None, trivia))
         mWhole, localBindingBuilder }
 
@@ -2910,7 +2912,7 @@ localBinding:
         let localBindingBuilder = 
           (fun xmlDoc attrs vis mLetKwd ->
             let spBind = DebugPointAtBinding.Yes (unionRanges mLetKwd mRhs)
-            let trivia = { LetKeyword = Some mLetKwd; EqualsRange = None }
+            let trivia = { LetKeyword = Some mLetKwd; EqualsRange = None; ExternKeyword = None }
             let rhsExpr = arbExpr("localBinding2", mRhs)
             mkSynBinding (xmlDoc, bindingPat) (vis, $1, $2, mBindLhs, spBind, optReturnType, rhsExpr, mRhs, [], attrs, None, trivia))
         mWhole, localBindingBuilder }

tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj

@@ -122,6 +122,9 @@
     <Compile Include="..\service\SyntaxTreeTests\AttributeTests.fs">
       <Link>SyntaxTree\AttributeTests.fs</Link>
     </Compile>
+    <Compile Include="..\service\SyntaxTreeTests\ExternTests.fs">
+      <Link>SyntaxTree\ExternTests.fs</Link>
+    </Compile>
     <Compile Include="..\service\FileSystemTests.fs">
       <Link>FileSystemTests.fs</Link>
     </Compile>

tests/FSharp.Compiler.Service.Tests/FSharp.CompilerService.SurfaceArea.netstandard.expected

@@ -9419,11 +9419,13 @@ FSharp.Compiler.SyntaxTrivia.SynBindingTrivia
 FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: FSharp.Compiler.SyntaxTrivia.SynBindingTrivia Zero
 FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: FSharp.Compiler.SyntaxTrivia.SynBindingTrivia get_Zero()
 FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range] EqualsRange
+FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range] ExternKeyword
 FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range] LetKeyword
 FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range] get_EqualsRange()
+FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range] get_ExternKeyword()
 FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range] get_LetKeyword()
 FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: System.String ToString()
-FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Void .ctor(Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range])
+FSharp.Compiler.SyntaxTrivia.SynBindingTrivia: Void .ctor(Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range])
 FSharp.Compiler.SyntaxTrivia.SynEnumCaseTrivia
 FSharp.Compiler.SyntaxTrivia.SynEnumCaseTrivia: FSharp.Compiler.Text.Range EqualsRange
 FSharp.Compiler.SyntaxTrivia.SynEnumCaseTrivia: FSharp.Compiler.Text.Range get_EqualsRange()

tests/service/SyntaxTreeTests/ExternTests.fs

@@ -0,0 +1,21 @@
+module FSharp.Compiler.Service.Tests.SyntaxTreeTests.ExternTests
+
+open FSharp.Compiler.Service.Tests.Common
+open FSharp.Compiler.Syntax
+open FSharp.Compiler.SyntaxTrivia
+open NUnit.Framework
+
+[<Test>]
+let ``extern keyword is present in trivia`` () =
+    let parseResults = getParseResults "extern void GetProcessHeap()"
+
+    match parseResults with
+    | ParsedInput.ImplFile(ParsedImplFileInput(contents = [
+                SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+                    SynModuleDecl.Let(bindings = [
+                        SynBinding(trivia = { ExternKeyword = Some mExtern  })
+                    ])
+                ])
+            ])) ->
+        assertRange (1, 0) (1, 6) mExtern
+    | _ -> Assert.Fail $"Could not get valid AST, got {parseResults}"