Remove unnecessary feature checks

We now check these with the spec set.

Author: hamishknight

Sources/SwiftParser/Declarations.swift

@@ -138,8 +138,6 @@ extension TokenConsumer {
  // FIXME: C++ parser returns true if this is a top-level non-"script" files.
  // But we don't have "is library" flag.
  return false
- case .rhs(._borrowing), .rhs(._consuming), .rhs(._mutating):
- return experimentalFeatures.contains(.referenceBindings)
  case .some(_):
  // All other decl start keywords unconditionally start a decl.
  return true
@@ -249,16 +247,8 @@ extension Parser {
  return RawDeclSyntax(self.parseMacroDeclaration(attrs: attrs, introducerHandle: handle))
  case (.lhs(.pound), let handle)?:
  return RawDeclSyntax(self.parseMacroExpansionDeclaration(attrs, handle))
- case (.rhs(let binding), let handle)?:
- switch binding {
- case ._mutating, ._borrowing, ._consuming:
- guard experimentalFeatures.contains(.referenceBindings) else {
- break
- }
- fallthrough
- case .let, .var, .inout:
- return RawDeclSyntax(self.parseBindingDeclaration(attrs, handle, inMemberDeclList: inMemberDeclList))
- }
+ case (.rhs, let handle)?:
+ return RawDeclSyntax(self.parseBindingDeclaration(attrs, handle, inMemberDeclList: inMemberDeclList))
  case nil:
  break
  }

Sources/SwiftParser/Patterns.swift

@@ -86,24 +86,16 @@ extension Parser {
  arena: self.arena
  )
  )
- case (.rhs(let binding), let handle)?:
- switch binding {
- case ._mutating, ._borrowing, ._consuming:
- guard experimentalFeatures.contains(.referenceBindings) else {
- break
- }
- fallthrough
- case .let, .var, .inout:
- let bindingSpecifier = self.eat(handle)
- let value = self.parsePattern()
- return RawPatternSyntax(
- RawValueBindingPatternSyntax(
- bindingSpecifier: bindingSpecifier,
- pattern: value,
- arena: self.arena
- )
+ case (.rhs, let handle)?:
+ let bindingSpecifier = self.eat(handle)
+ let value = self.parsePattern()
+ return RawPatternSyntax(
+ RawValueBindingPatternSyntax(
+ bindingSpecifier: bindingSpecifier,
+ pattern: value,
+ arena: self.arena
  )
- }
+ )
  case nil:
  break
  }
@@ -227,24 +219,16 @@ extension Parser {
  arena: self.arena
  )
  )
- case (.rhs(let binding), let handle)?:
- switch binding {
- case ._mutating, ._borrowing, ._consuming:
- guard experimentalFeatures.contains(.referenceBindings) else {
- break
- }
- fallthrough
- case .let, .var, .inout:
- let bindingSpecifier = self.eat(handle)
- let value = self.parseMatchingPattern(context: .bindingIntroducer)
- return RawPatternSyntax(
- RawValueBindingPatternSyntax(
- bindingSpecifier: bindingSpecifier,
- pattern: value,
- arena: self.arena
- )
+ case (.rhs, let handle)?:
+ let bindingSpecifier = self.eat(handle)
+ let value = self.parseMatchingPattern(context: .bindingIntroducer)
+ return RawPatternSyntax(
+ RawValueBindingPatternSyntax(
+ bindingSpecifier: bindingSpecifier,
+ pattern: value,
+ arena: self.arena
  )
- }
+ )
  case nil:
  break
  }
@@ -311,17 +295,9 @@ extension Parser.Lookahead {
  return true
  case (.lhs(.leftParen), _)?:
  return self.canParsePatternTuple()
- case (.rhs(let binding), let handle)?:
- switch binding {
- case ._mutating, ._borrowing, ._consuming:
- guard experimentalFeatures.contains(.referenceBindings) else {
- return false
- }
- fallthrough
- case .let, .var, .inout:
- self.eat(handle)
- return self.canParsePattern()
- }
+ case (.rhs, let handle)?:
+ self.eat(handle)
+ return self.canParsePattern()
  case nil:
  return false
  }