Add SynPat.ListCons. (#14010)

src/Compiler/Checking/CheckPatterns.fs

@@ -289,6 +289,11 @@ and TcPat warnOnUpper (cenv: cenv) env valReprInfo vFlags (patEnv: TcPatLinearEn
     | SynPat.Or (pat1, pat2, m, _) ->
         TcPatOr warnOnUpper cenv env vFlags patEnv ty pat1 pat2 m
 
+    | SynPat.ListCons(pat1, pat2, m, trivia) ->
+        let longDotId = SynLongIdent((mkSynCaseName trivia.ColonColonRange opNameCons), [], [Some (FSharp.Compiler.SyntaxTrivia.IdentTrivia.OriginalNotation "::")])
+        let args = SynArgPats.Pats [ SynPat.Tuple(false, [ pat1; pat2 ], m) ]
+        TcPatLongIdent warnOnUpper cenv env ad valReprInfo vFlags patEnv ty (longDotId, None, args, None, m)
+
     | SynPat.Ands (pats, m) ->
         TcPatAnds warnOnUpper cenv env vFlags patEnv ty pats m
 

src/Compiler/Service/ServiceParseTreeWalk.fs

@@ -789,7 +789,8 @@ module SyntaxTraversal =
                 match p with
                 | SynPat.Paren (p, _) -> traversePat path p
                 | SynPat.As (p1, p2, _)
-                | SynPat.Or (p1, p2, _, _) -> [ p1; p2 ] |> List.tryPick (traversePat path)
+                | SynPat.Or (p1, p2, _, _)
+                | SynPat.ListCons (p1, p2, _, _) -> [ p1; p2 ] |> List.tryPick (traversePat path)
                 | SynPat.Ands (ps, _)
                 | SynPat.Tuple (_, ps, _)
                 | SynPat.ArrayOrList (_, ps, _) -> ps |> List.tryPick (traversePat path)

src/Compiler/Service/ServiceParsedInputOps.fs

@@ -619,7 +619,8 @@ module ParsedInput =
             | SynPat.As (pat1, pat2, _) -> List.tryPick walkPat [ pat1; pat2 ]
             | SynPat.Typed (pat, t, _) -> walkPat pat |> Option.orElseWith (fun () -> walkType t)
             | SynPat.Attrib (pat, Attributes attrs, _) -> walkPat pat |> Option.orElseWith (fun () -> List.tryPick walkAttribute attrs)
-            | SynPat.Or (pat1, pat2, _, _) -> List.tryPick walkPat [ pat1; pat2 ]
+            | SynPat.Or (pat1, pat2, _, _)
+            | SynPat.ListCons (pat1, pat2, _, _) -> List.tryPick walkPat [ pat1; pat2 ]
             | SynPat.LongIdent (typarDecls = typars; argPats = ConstructorPats pats; range = r) ->
                 ifPosInRange r (fun _ -> kind)
                 |> Option.orElseWith (fun () ->
@@ -1638,7 +1639,8 @@ module ParsedInput =
                 walkPat pat
                 List.iter walkAttribute attrs
             | SynPat.As (pat1, pat2, _)
-            | SynPat.Or (pat1, pat2, _, _) -> List.iter walkPat [ pat1; pat2 ]
+            | SynPat.Or (pat1, pat2, _, _)
+            | SynPat.ListCons (pat1, pat2, _, _) -> List.iter walkPat [ pat1; pat2 ]
             | SynPat.LongIdent (longDotId = ident; typarDecls = typars; argPats = ConstructorPats pats) ->
                 addLongIdentWithDots ident
 

src/Compiler/Service/ServiceXmlDocParser.fs

@@ -25,6 +25,7 @@ module XmlDocParsing =
         | SynPat.Typed (pat, _type, _range) -> digNamesFrom pat
         | SynPat.Attrib (pat, _attrs, _range) -> digNamesFrom pat
         | SynPat.LongIdent(argPats = ConstructorPats pats) -> pats |> List.collect digNamesFrom
+        | SynPat.ListCons (p1, p2, _, _) -> List.collect digNamesFrom [ p1; p2 ]
         | SynPat.Tuple (_, pats, _range) -> pats |> List.collect digNamesFrom
         | SynPat.Paren (pat, _range) -> digNamesFrom pat
         | SynPat.OptionalVal (id, _) -> [ id.idText ]

src/Compiler/SyntaxTree/SyntaxTree.fs

@@ -908,6 +908,8 @@ type SynPat =
 
     | Or of lhsPat: SynPat * rhsPat: SynPat * range: range * trivia: SynPatOrTrivia
 
+    | ListCons of lhsPat: SynPat * rhsPat: SynPat * range: range * trivia: SynPatListConsTrivia
+
     | Ands of pats: SynPat list * range: range
 
     | As of lhsPat: SynPat * rhsPat: SynPat * range: range
@@ -953,6 +955,7 @@ type SynPat =
         | SynPat.Wild (range = m)
         | SynPat.Named (range = m)
         | SynPat.Or (range = m)
+        | SynPat.ListCons (range = m)
         | SynPat.Ands (range = m)
         | SynPat.As (range = m)
         | SynPat.LongIdent (range = m)

src/Compiler/SyntaxTree/SyntaxTree.fsi

@@ -1050,6 +1050,9 @@ type SynPat =
     /// A disjunctive pattern 'pat1 | pat2'
     | Or of lhsPat: SynPat * rhsPat: SynPat * range: range * trivia: SynPatOrTrivia
 
+    /// A conjunctive pattern 'pat1 :: pat2'
+    | ListCons of lhsPat: SynPat * rhsPat: SynPat * range: range * trivia: SynPatListConsTrivia
+
     /// A conjunctive pattern 'pat1 & pat2'
     | Ands of pats: SynPat list * range: range
 

src/Compiler/SyntaxTree/SyntaxTrivia.fs

@@ -122,6 +122,9 @@ type SynUnionCaseTrivia = { BarRange: range option }
 [<NoEquality; NoComparison>]
 type SynPatOrTrivia = { BarRange: range }
 
+[<NoEquality; NoComparison>]
+type SynPatListConsTrivia = { ColonColonRange: range }
+
 [<NoEquality; NoComparison>]
 type SynTypeDefnTrivia =
     {

src/Compiler/SyntaxTree/SyntaxTrivia.fsi

@@ -199,6 +199,14 @@ type SynPatOrTrivia =
         BarRange: range
     }
 
+/// Represents additional information for SynPat.Cons
+[<NoEquality; NoComparison>]
+type SynPatListConsTrivia =
+    {
+        /// The syntax range of the `::` token.
+        ColonColonRange: range
+    }
+
 /// Represents additional information for SynTypeDefn
 [<NoEquality; NoComparison>]
 type SynTypeDefnTrivia =

src/Compiler/pars.fsy

@@ -3124,7 +3124,8 @@ headBindingPattern:
         SynPat.Or($1, $3, rhs2 parseState 1 3, { BarRange = mBar }) }
 
   | headBindingPattern COLON_COLON  headBindingPattern 
-      { SynPat.LongIdent (SynLongIdent(mkSynCaseName (rhs parseState 2) opNameCons, [], [ Some (IdentTrivia.OriginalNotation "::") ]), None, None, SynArgPats.Pats [SynPat.Tuple (false, [$1;$3], rhs2 parseState 1 3)], None, lhs parseState) }
+      { let mColonColon = rhs parseState 2
+        SynPat.ListCons($1, $3, rhs2 parseState 1 3, { ColonColonRange = mColonColon }) }
 
   | tuplePatternElements %prec pat_tuple
       { let pats = normalizeTuplePat $1
@@ -3398,7 +3399,8 @@ parenPattern:
         SynPat.Attrib($2, $1, mLhs) } 
 
   | parenPattern COLON_COLON  parenPattern 
-      { SynPat.LongIdent (SynLongIdent(mkSynCaseName (rhs parseState 2) opNameCons, [], [ Some (IdentTrivia.OriginalNotation "::") ]), None, None, SynArgPats.Pats [ SynPat.Tuple (false, [$1;$3], rhs2 parseState 1 3) ], None, lhs parseState) }
+      { let mColonColon = rhs parseState 2
+        SynPat.ListCons($1, $3, rhs2 parseState 1 3, { ColonColonRange = mColonColon }) }
 
   | constrPattern { $1 }
 

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

@@ -8004,6 +8004,14 @@ FSharp.Compiler.Syntax.SynPat+IsInst: FSharp.Compiler.Syntax.SynType get_pat()
 FSharp.Compiler.Syntax.SynPat+IsInst: FSharp.Compiler.Syntax.SynType pat
 FSharp.Compiler.Syntax.SynPat+IsInst: FSharp.Compiler.Text.Range get_range()
 FSharp.Compiler.Syntax.SynPat+IsInst: FSharp.Compiler.Text.Range range
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.Syntax.SynPat get_lhsPat()
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.Syntax.SynPat get_rhsPat()
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.Syntax.SynPat lhsPat
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.Syntax.SynPat rhsPat
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia get_trivia()
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia trivia
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.Text.Range get_range()
+FSharp.Compiler.Syntax.SynPat+ListCons: FSharp.Compiler.Text.Range range
 FSharp.Compiler.Syntax.SynPat+LongIdent: FSharp.Compiler.Syntax.SynArgPats argPats
 FSharp.Compiler.Syntax.SynPat+LongIdent: FSharp.Compiler.Syntax.SynArgPats get_argPats()
 FSharp.Compiler.Syntax.SynPat+LongIdent: FSharp.Compiler.Syntax.SynLongIdent get_longDotId()
@@ -8059,6 +8067,7 @@ FSharp.Compiler.Syntax.SynPat+Tags: Int32 DeprecatedCharRange
 FSharp.Compiler.Syntax.SynPat+Tags: Int32 FromParseError
 FSharp.Compiler.Syntax.SynPat+Tags: Int32 InstanceMember
 FSharp.Compiler.Syntax.SynPat+Tags: Int32 IsInst
+FSharp.Compiler.Syntax.SynPat+Tags: Int32 ListCons
 FSharp.Compiler.Syntax.SynPat+Tags: Int32 LongIdent
 FSharp.Compiler.Syntax.SynPat+Tags: Int32 Named
 FSharp.Compiler.Syntax.SynPat+Tags: Int32 Null
@@ -8093,6 +8102,7 @@ FSharp.Compiler.Syntax.SynPat: Boolean IsDeprecatedCharRange
 FSharp.Compiler.Syntax.SynPat: Boolean IsFromParseError
 FSharp.Compiler.Syntax.SynPat: Boolean IsInstanceMember
 FSharp.Compiler.Syntax.SynPat: Boolean IsIsInst
+FSharp.Compiler.Syntax.SynPat: Boolean IsListCons
 FSharp.Compiler.Syntax.SynPat: Boolean IsLongIdent
 FSharp.Compiler.Syntax.SynPat: Boolean IsNamed
 FSharp.Compiler.Syntax.SynPat: Boolean IsNull
@@ -8113,6 +8123,7 @@ FSharp.Compiler.Syntax.SynPat: Boolean get_IsDeprecatedCharRange()
 FSharp.Compiler.Syntax.SynPat: Boolean get_IsFromParseError()
 FSharp.Compiler.Syntax.SynPat: Boolean get_IsInstanceMember()
 FSharp.Compiler.Syntax.SynPat: Boolean get_IsIsInst()
+FSharp.Compiler.Syntax.SynPat: Boolean get_IsListCons()
 FSharp.Compiler.Syntax.SynPat: Boolean get_IsLongIdent()
 FSharp.Compiler.Syntax.SynPat: Boolean get_IsNamed()
 FSharp.Compiler.Syntax.SynPat: Boolean get_IsNull()
@@ -8133,6 +8144,7 @@ FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewDeprecatedCharRa
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewFromParseError(FSharp.Compiler.Syntax.SynPat, FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewInstanceMember(FSharp.Compiler.Syntax.Ident, FSharp.Compiler.Syntax.Ident, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynAccess], FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewIsInst(FSharp.Compiler.Syntax.SynType, FSharp.Compiler.Text.Range)
+FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewListCons(FSharp.Compiler.Syntax.SynPat, FSharp.Compiler.Syntax.SynPat, FSharp.Compiler.Text.Range, FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia)
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewLongIdent(FSharp.Compiler.Syntax.SynLongIdent, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.Ident], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynValTyparDecls], FSharp.Compiler.Syntax.SynArgPats, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynAccess], FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewNamed(FSharp.Compiler.Syntax.SynIdent, Boolean, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Syntax.SynAccess], FSharp.Compiler.Text.Range)
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat NewNull(FSharp.Compiler.Text.Range)
@@ -8153,6 +8165,7 @@ FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+DeprecatedCharRange
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+FromParseError
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+InstanceMember
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+IsInst
+FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+ListCons
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+LongIdent
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+Named
 FSharp.Compiler.Syntax.SynPat: FSharp.Compiler.Syntax.SynPat+Null
@@ -9556,6 +9569,11 @@ FSharp.Compiler.SyntaxTrivia.SynModuleSigDeclNestedModuleTrivia: Microsoft.FShar
 FSharp.Compiler.SyntaxTrivia.SynModuleSigDeclNestedModuleTrivia: Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range] get_ModuleKeyword()
 FSharp.Compiler.SyntaxTrivia.SynModuleSigDeclNestedModuleTrivia: System.String ToString()
 FSharp.Compiler.SyntaxTrivia.SynModuleSigDeclNestedModuleTrivia: Void .ctor(Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.Text.Range])
+FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia
+FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia: FSharp.Compiler.Text.Range ColonColonRange
+FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia: FSharp.Compiler.Text.Range get_ColonColonRange()
+FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia: System.String ToString()
+FSharp.Compiler.SyntaxTrivia.SynPatListConsTrivia: Void .ctor(FSharp.Compiler.Text.Range)
 FSharp.Compiler.SyntaxTrivia.SynPatOrTrivia
 FSharp.Compiler.SyntaxTrivia.SynPatOrTrivia: FSharp.Compiler.Text.Range BarRange
 FSharp.Compiler.SyntaxTrivia.SynPatOrTrivia: FSharp.Compiler.Text.Range get_BarRange()

tests/service/SyntaxTreeTests/PatternTests.fs

@@ -73,10 +73,10 @@ let (head::tail) =  [ 1;2;4]
     match parseResults with
     | ParsedInput.ImplFile (ParsedImplFileInput (contents = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
         SynModuleDecl.Let(
-            bindings = [ SynBinding(headPat = SynPat.Paren(SynPat.LongIdent(longDotId = SynLongIdent([ opColonColonIdent ], _, [ Some (IdentTrivia.OriginalNotation "::") ])), _)) ]
+            bindings = [ SynBinding(headPat = SynPat.Paren(pat = SynPat.ListCons(trivia = trivia))) ]
         )
     ]) ])) ->
-        Assert.AreEqual("op_ColonColon", opColonColonIdent.idText)
+        assertRange (2,9) (2,11) trivia.ColonColonRange
     | _ -> Assert.Fail $"Could not get valid AST, got {parseResults}"
 
 [<Test>]
@@ -92,11 +92,11 @@ match x with
     | ParsedInput.ImplFile (ParsedImplFileInput (contents = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
         SynModuleDecl.Expr(
             expr = SynExpr.Match(clauses = [
-                SynMatchClause(pat = SynPat.LongIdent(longDotId = SynLongIdent([ opColonColonIdent ], _, [ Some (IdentTrivia.OriginalNotation "::") ])))
+                SynMatchClause(pat = SynPat.ListCons(trivia = trivia))
             ])
         )
     ]) ])) ->
-        Assert.AreEqual("op_ColonColon", opColonColonIdent.idText)
+        assertRange (3, 9) (3, 11) trivia.ColonColonRange
     | _ -> Assert.Fail $"Could not get valid AST, got {parseResults}"
 
 [<Test>]
@@ -122,3 +122,19 @@ match data with
     ]) ])) ->
         assertRange (3, 13) (5, 13) trivia.ParenRange
     | _ -> Assert.Fail $"Could not get valid AST, got {parseResults}"
+
+[<Test>]
+let ``:: in head pattern`` () =
+    let parseResults =
+        getParseResults
+            """
+let 1 :: _ = [ 4; 5; 6 ]
+"""
+    
+    match  parseResults with
+    | ParsedInput.ImplFile(ParsedImplFileInput(contents = [ SynModuleOrNamespace(decls = [
+        SynModuleDecl.Let(bindings = [ SynBinding(headPat =
+            SynPat.ListCons(trivia = trivia)) ])
+    ]) ])) ->
+        assertRange (2,6) (2, 8) trivia.ColonColonRange
+    | _ -> Assert.Fail $"Could not get valid AST, got {parseResults}"