Remove always-on WildCardInForLoop language feature flag

src/Compiler/FSComp.txt

@@ -1564,7 +1564,6 @@ nativeResourceFormatError,"Stream does not begin with a null resource and is not
 nativeResourceHeaderMalformed,"Resource header beginning at offset %s is malformed."
 formatDashItem," - %s"
 featureSingleUnderscorePattern,"single underscore pattern"
-featureWildCardInForLoop,"wild card in for loop"
 featureRelaxWhitespace,"whitespace relaxation"
 featureNameOf,"nameof"
 featureImplicitYield,"implicit yield"

src/Compiler/Facilities/LanguageFeatures.fs

@@ -17,7 +17,6 @@ module internal FSharp.Compiler.Features
 [<RequireQualifiedAccess>]
 type LanguageFeature =
     | SingleUnderscorePattern
-    | WildCardInForLoop
     | RelaxWhitespace
     | RelaxWhitespace2
     | NameOf
@@ -153,7 +152,6 @@ type LanguageVersion(versionText, ?disabledFeaturesArray: LanguageFeature array)
             [
                 // F# 4.7
                 LanguageFeature.SingleUnderscorePattern, languageVersion47
-                LanguageFeature.WildCardInForLoop, languageVersion47
                 LanguageFeature.RelaxWhitespace, languageVersion47
                 LanguageFeature.ImplicitYield, languageVersion47
 
@@ -365,7 +363,6 @@ type LanguageVersion(versionText, ?disabledFeaturesArray: LanguageFeature array)
     static member GetFeatureString feature =
         match feature with
         | LanguageFeature.SingleUnderscorePattern -> FSComp.SR.featureSingleUnderscorePattern ()
-        | LanguageFeature.WildCardInForLoop -> FSComp.SR.featureWildCardInForLoop ()
         | LanguageFeature.RelaxWhitespace -> FSComp.SR.featureRelaxWhitespace ()
         | LanguageFeature.RelaxWhitespace2 -> FSComp.SR.featureRelaxWhitespace2 ()
         | LanguageFeature.NameOf -> FSComp.SR.featureNameOf ()

src/Compiler/Facilities/LanguageFeatures.fsi

@@ -7,7 +7,6 @@ module internal FSharp.Compiler.Features
 [<RequireQualifiedAccess>]
 type LanguageFeature =
     | SingleUnderscorePattern
-    | WildCardInForLoop
     | RelaxWhitespace
     | RelaxWhitespace2
     | NameOf

src/Compiler/SyntaxTree/ParseHelpers.fs

@@ -978,9 +978,9 @@ let mkDefnBindings (mWhole, BindingSetPreAttrs(_, isRec, isUse, declsPreAttrs, _
 
     attrDecls @ letDecls
 
-let idOfPat (parseState: IParseState) m p =
+let idOfPat m p =
     match p with
-    | SynPat.Wild r when parseState.LexBuffer.SupportsFeature LanguageFeature.WildCardInForLoop -> mkSynId r "_"
+    | SynPat.Wild r -> mkSynId r "_"
     | SynPat.Named(SynIdent(id, _), false, _, _) -> id
     | SynPat.LongIdent(longDotId = SynLongIdent([ id ], _, _); typarDecls = None; argPats = SynArgPats.Pats []; accessibility = None) -> id
     | _ -> raiseParseErrorAt m (FSComp.SR.parsIntegerForLoopRequiresSimpleIdentifier ())

src/Compiler/SyntaxTree/ParseHelpers.fsi

@@ -229,7 +229,7 @@ val mkDefnBindings:
     mWhole: range * BindingSet * attrs: SynAttributes * vis: SynAccess option * attrsm: range * mIn: range option ->
         SynModuleDecl list
 
-val idOfPat: parseState: IParseState -> m: range -> p: SynPat -> Ident
+val idOfPat: m: range -> p: SynPat -> Ident
 
 val checkForMultipleAugmentations: m: range -> a1: 'a list -> a2: 'a list -> 'a list
 

src/Compiler/pars.fsy

@@ -5750,7 +5750,7 @@ forLoopRange:
   | parenPattern EQUALS declExpr forLoopDirection declExpr
       { let mEquals = rhs parseState 2
         let spTo = DebugPointAtInOrTo.Yes(rhs parseState 4)
-        idOfPat parseState (rhs parseState 1) $1, Some mEquals, $3, $4, $5, spTo }
+        idOfPat (rhs parseState 1) $1, Some mEquals, $3, $4, $5, spTo }
 
 forLoopDirection:
   | TO { true }