diff --git a/src/fsharp/CheckExpressions.fs b/src/fsharp/CheckExpressions.fs
index 352aa63278a..6bb4f426722 100644
--- a/src/fsharp/CheckExpressions.fs
+++ b/src/fsharp/CheckExpressions.fs
@@ -810,7 +810,8 @@ let TcConst cenv ty m env c =
     | SynConst.Measure(SynConst.UInt64 i, _, _) when expandedMeasurablesEnabled -> unifyMeasureArg (i=0UL) cenv.g.puint64_tcr c; Const.UInt64 i
     | SynConst.Measure(SynConst.UIntPtr i, _, _) when expandedMeasurablesEnabled -> unifyMeasureArg (i=0UL) cenv.g.punativeint_tcr c; Const.UIntPtr i
     | SynConst.Char c -> unif cenv.g.char_ty; Const.Char c
-    | SynConst.String (s, _, _) -> unif cenv.g.string_ty; Const.String s
+    | SynConst.String (s, _, _)
+    | SynConst.SourceIdentifier (_, s, _) -> unif cenv.g.string_ty; Const.String s
     | SynConst.UserNum _ -> error (InternalError(FSComp.SR.tcUnexpectedBigRationalConstant(), m))
     | SynConst.Measure _ -> error (Error(FSComp.SR.tcInvalidTypeForUnitsOfMeasure(), m))
     | SynConst.UInt16s _ -> error (InternalError(FSComp.SR.tcUnexpectedConstUint16Array(), m))
diff --git a/src/fsharp/SyntaxTree.fs b/src/fsharp/SyntaxTree.fs
index 415055ac092..703fe29e5a6 100644
--- a/src/fsharp/SyntaxTree.fs
+++ b/src/fsharp/SyntaxTree.fs
@@ -116,10 +116,14 @@ type SynConst =
     | UInt16s of uint16[]
 
     | Measure of constant: SynConst * constantRange: Range * SynMeasure
+    
+    | SourceIdentifier of constant: string * value: string * range: Range
 
     member c.Range dflt =
         match c with
-        | SynConst.String (_, _, m0) | SynConst.Bytes (_, _, m0) -> m0
+        | SynConst.String (_, _, m0)
+        | SynConst.Bytes (_, _, m0)
+        | SynConst.SourceIdentifier(_, _, m0) -> m0
         | _ -> dflt
 
 [<NoEquality; NoComparison; RequireQualifiedAccess>]
diff --git a/src/fsharp/SyntaxTree.fsi b/src/fsharp/SyntaxTree.fsi
index 4e94d6d86ed..8d2d4414912 100644
--- a/src/fsharp/SyntaxTree.fsi
+++ b/src/fsharp/SyntaxTree.fsi
@@ -152,6 +152,10 @@ type SynConst =
 
     /// Old comment: "we never iterate, so the const here is not another SynConst.Measure"
     | Measure of constant: SynConst * constantRange: range * SynMeasure
+    
+    /// Source Line, File, and Path Identifiers
+    /// Containing both the original value as the evaluated value.
+    | SourceIdentifier of constant: string * value: string * range: Range
 
     /// Gets the syntax range of this construct
     member Range: dflt: range -> range
diff --git a/src/fsharp/lexhelp.fs b/src/fsharp/lexhelp.fs
index 94c4be068d4..8fa659de6ee 100644
--- a/src/fsharp/lexhelp.fs
+++ b/src/fsharp/lexhelp.fs
@@ -396,11 +396,11 @@ module Keywords =
 
                 if String.IsNullOrEmpty dirname then dirname
                 else PathMap.applyDir args.pathMap dirname
-                |> KEYWORD_STRING
+                |> fun dir -> KEYWORD_STRING(s, dir)
             | "__SOURCE_FILE__" -> 
-                KEYWORD_STRING (System.IO.Path.GetFileName((FileIndex.fileOfFileIndex lexbuf.StartPos.FileIndex))) 
+                KEYWORD_STRING (s, System.IO.Path.GetFileName((FileIndex.fileOfFileIndex lexbuf.StartPos.FileIndex))) 
             | "__LINE__" -> 
-                KEYWORD_STRING (string lexbuf.StartPos.Line)
+                KEYWORD_STRING (s, string lexbuf.StartPos.Line)
             | _ -> 
                 IdentifierToken args lexbuf s
 
diff --git a/src/fsharp/pars.fsy b/src/fsharp/pars.fsy
index a287f3ad149..97b866b7695 100644
--- a/src/fsharp/pars.fsy
+++ b/src/fsharp/pars.fsy
@@ -202,7 +202,7 @@ let rangeOfLongIdent(lid:LongIdent) =
 %token <string * ParseHelpers.LexerContinuation> INTERP_STRING_END 
 %token <ParseHelpers.LexerContinuation> LBRACE RBRACE
 
-%token <string> KEYWORD_STRING // Like __SOURCE_DIRECTORY__
+%token <string * string> KEYWORD_STRING // Like __SOURCE_DIRECTORY__
 %token <string> IDENT 
 %token <string> HASH_IDENT 
 %token <string> INFIX_STAR_STAR_OP 
@@ -646,7 +646,7 @@ hashDirectiveArgs:
 
 /* One argument to a #directive */
 hashDirectiveArg: 
-  | stringOrKeywordString 
+  | string 
       { let s, _ = $1
         s }
       
@@ -2214,7 +2214,7 @@ tyconDefnOrSpfnSimpleRepr:
        SynTypeDefnSimpleRepr.Record ($2, $3, lhs parseState) }
 
   /* An inline-assembly type definition, for FSharp.Core library only */
-  | opt_attributes opt_declVisibility LPAREN HASH stringOrKeywordString HASH rparen
+  | opt_attributes opt_declVisibility LPAREN HASH string HASH rparen
      { if not (isNil $1) then errorR(Error(FSComp.SR.parsAttributesIllegalHere(), rhs parseState 1))
        let lhsm = lhs parseState
        libraryOnlyError lhsm
@@ -2922,10 +2922,14 @@ rawConstant:
   | BIGNUM
     { SynConst.UserNum $1 } 
 
-  | stringOrKeywordString
+  | string
     { let s, synStringKind = $1
       SynConst.String (s, synStringKind, lhs parseState) } 
 
+  | sourceIdentifier
+    { let c,v = $1
+      SynConst.SourceIdentifier (c, v, lhs parseState) }
+
   | BYTEARRAY
     { let (v, synByteStringKind, _) = $1
       SynConst.Bytes (v, synByteStringKind, lhs parseState) }
@@ -4518,7 +4522,7 @@ forLoopDirection:
   | DOWNTO { false }
 
 inlineAssemblyExpr:
-  | HASH stringOrKeywordString opt_inlineAssemblyTypeArg optCurriedArgExprs  optInlineAssemblyReturnTypes HASH 
+  | HASH string opt_inlineAssemblyTypeArg optCurriedArgExprs  optInlineAssemblyReturnTypes HASH 
       { libraryOnlyWarning (lhs parseState)
         let (s, _), sm = $2, rhs parseState 2
         (fun m ->
@@ -5556,11 +5560,13 @@ colonOrEquals:
   | EQUALS { } 
 
 /* A literal string or a string from a keyword like __SOURCE_FILE__ */
-stringOrKeywordString:
+string:
   | STRING 
      { let (s, synStringKind, _) = $1
        s, synStringKind }
-  | KEYWORD_STRING { $1, SynStringKind.Regular }
+
+sourceIdentifier:
+  | KEYWORD_STRING { $1 }
 
 interpolatedStringFill:
   | declExpr
diff --git a/tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs b/tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs
index ab20cf8f211..00665a2e22c 100644
--- a/tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs
+++ b/tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs
@@ -5788,6 +5788,12 @@ FSharp.Compiler.Syntax.SynConst+SByte: SByte Item
 FSharp.Compiler.Syntax.SynConst+SByte: SByte get_Item()
 FSharp.Compiler.Syntax.SynConst+Single: Single Item
 FSharp.Compiler.Syntax.SynConst+Single: Single get_Item()
+FSharp.Compiler.Syntax.SynConst+SourceIdentifier: FSharp.Compiler.Text.Range get_range()
+FSharp.Compiler.Syntax.SynConst+SourceIdentifier: FSharp.Compiler.Text.Range range
+FSharp.Compiler.Syntax.SynConst+SourceIdentifier: System.String constant
+FSharp.Compiler.Syntax.SynConst+SourceIdentifier: System.String get_constant()
+FSharp.Compiler.Syntax.SynConst+SourceIdentifier: System.String get_value()
+FSharp.Compiler.Syntax.SynConst+SourceIdentifier: System.String value
 FSharp.Compiler.Syntax.SynConst+String: FSharp.Compiler.Syntax.SynStringKind get_synStringKind()
 FSharp.Compiler.Syntax.SynConst+String: FSharp.Compiler.Syntax.SynStringKind synStringKind
 FSharp.Compiler.Syntax.SynConst+String: FSharp.Compiler.Text.Range get_range()
@@ -5807,6 +5813,7 @@ FSharp.Compiler.Syntax.SynConst+Tags: Int32 IntPtr
 FSharp.Compiler.Syntax.SynConst+Tags: Int32 Measure
 FSharp.Compiler.Syntax.SynConst+Tags: Int32 SByte
 FSharp.Compiler.Syntax.SynConst+Tags: Int32 Single
+FSharp.Compiler.Syntax.SynConst+Tags: Int32 SourceIdentifier
 FSharp.Compiler.Syntax.SynConst+Tags: Int32 String
 FSharp.Compiler.Syntax.SynConst+Tags: Int32 UInt16
 FSharp.Compiler.Syntax.SynConst+Tags: Int32 UInt16s
@@ -5842,6 +5849,7 @@ FSharp.Compiler.Syntax.SynConst: Boolean IsIntPtr
 FSharp.Compiler.Syntax.SynConst: Boolean IsMeasure
 FSharp.Compiler.Syntax.SynConst: Boolean IsSByte
 FSharp.Compiler.Syntax.SynConst: Boolean IsSingle
+FSharp.Compiler.Syntax.SynConst: Boolean IsSourceIdentifier
 FSharp.Compiler.Syntax.SynConst: Boolean IsString
 FSharp.Compiler.Syntax.SynConst: Boolean IsUInt16
 FSharp.Compiler.Syntax.SynConst: Boolean IsUInt16s
@@ -5863,6 +5871,7 @@ FSharp.Compiler.Syntax.SynConst: Boolean get_IsIntPtr()
 FSharp.Compiler.Syntax.SynConst: Boolean get_IsMeasure()
 FSharp.Compiler.Syntax.SynConst: Boolean get_IsSByte()
 FSharp.Compiler.Syntax.SynConst: Boolean get_IsSingle()
+FSharp.Compiler.Syntax.SynConst: Boolean get_IsSourceIdentifier()
 FSharp.Compiler.Syntax.SynConst: Boolean get_IsString()
 FSharp.Compiler.Syntax.SynConst: Boolean get_IsUInt16()
 FSharp.Compiler.Syntax.SynConst: Boolean get_IsUInt16s()
@@ -5884,6 +5893,7 @@ FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewIntPtr(Int64
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewMeasure(FSharp.Compiler.Syntax.SynConst, FSharp.Compiler.Text.Range, FSharp.Compiler.Syntax.SynMeasure)
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewSByte(SByte)
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewSingle(Single)
+FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewSourceIdentifier(System.String, System.String, FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewString(System.String, FSharp.Compiler.Syntax.SynStringKind, FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewUInt16(UInt16)
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst NewUInt16s(UInt16[])
@@ -5906,6 +5916,7 @@ FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+IntPtr
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+Measure
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+SByte
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+Single
+FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+SourceIdentifier
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+String
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+Tags
 FSharp.Compiler.Syntax.SynConst: FSharp.Compiler.Syntax.SynConst+UInt16
diff --git a/tests/service/Symbols.fs b/tests/service/Symbols.fs
index d62e57c930a..03e32098547 100644
--- a/tests/service/Symbols.fs
+++ b/tests/service/Symbols.fs
@@ -764,4 +764,47 @@ with
         ]) ])) ->
             assertRange (6, 2) (6, 21) range
             assertRange (6, 2) (6, 21) clause.Range
+        | _ -> Assert.Fail "Could not get valid AST"
+
+module SourceIdentifiers =
+    [<Test>]
+    let ``__LINE__`` () =
+        let parseResults = 
+            getParseResults
+                """
+__LINE__"""
+
+        match parseResults with
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+            SynModuleDecl.DoExpr(expr = SynExpr.Const(SynConst.SourceIdentifier("__LINE__", "2", range), _))
+        ]) ])) ->
+            assertRange (2, 0) (2, 8) range
+        | _ -> Assert.Fail "Could not get valid AST"
+
+    [<Test>]
+    let ``__SOURCE_DIRECTORY__`` () =
+        let parseResults = 
+            getParseResults
+                """
+__SOURCE_DIRECTORY__"""
+
+        match parseResults with
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+            SynModuleDecl.DoExpr(expr = SynExpr.Const(SynConst.SourceIdentifier("__SOURCE_DIRECTORY__", _, range), _))
+        ]) ])) ->
+            assertRange (2, 0) (2, 20) range
+        | _ -> Assert.Fail "Could not get valid AST"
+        
+    [<Test>]
+    let ``__SOURCE_FILE__`` () =
+        let parseResults = 
+            getParseResults
+                """
+__SOURCE_FILE__"""
+
+        match parseResults with
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+            SynModuleDecl.DoExpr(expr = SynExpr.Const(SynConst.SourceIdentifier("__SOURCE_FILE__", _, range), _))
+        ]) ])) ->
+            assertRange (2, 0) (2, 15) range
         | _ -> Assert.Fail "Could not get valid AST"
\ No newline at end of file