Remove bespoke parsing for #_hasSymbol

Author: DougGregor

Sources/SwiftParser/Lexer/Cursor.swift

@@ -1465,7 +1465,6 @@ extension Lexer.Cursor {
     case "endif": kind = .poundEndifKeyword
     case "available": kind = .poundAvailableKeyword
     case "unavailable": kind = .poundUnavailableKeyword
-    case "_hasSymbol": kind = .poundHasSymbolKeyword
     default:
       // If we didn't find a match, then just return `.pound`.  This is highly
       // dubious in terms of error recovery, but is useful for code completion and

Sources/SwiftParser/Statements.swift

@@ -252,11 +252,6 @@ extension Parser {
       return self.parsePoundAvailableConditionElement()
     }
 
-    // Parse a #_hasSymbol condition if present.
-    if self.at(.poundHasSymbolKeyword) {
-      return .hasSymbol(self.parsePoundHasSymbolConditionElement())
-    }
-
     // Parse the basic expression case.  If we have a leading let/var/case
     // keyword or an assignment, then we know this is a binding.
     guard self.at(any: [.keyword(.let), .keyword(.var), .keyword(.case)]) else {
@@ -375,30 +370,6 @@ extension Parser {
       )
     )
   }
-
-  /// Parse a `#_hasSymbol` condition.
-  ///
-  /// Grammar
-  /// =======
-  ///
-  ///     has-symbol-condition → '#_hasSymbol' '(' expr ')'
-  @_spi(RawSyntax)
-  public mutating func parsePoundHasSymbolConditionElement() -> RawHasSymbolConditionSyntax {
-    let (unexpectedBeforeKeyword, keyword) = self.expect(.poundHasSymbolKeyword)
-    let (unexpectedBeforeLParen, lparen) = self.expect(.leftParen)
-    let expr = self.parseExpression()
-    let (unexpectedBeforeRParen, rparen) = self.expect(.rightParen)
-    return RawHasSymbolConditionSyntax(
-      unexpectedBeforeKeyword,
-      hasSymbolKeyword: keyword,
-      unexpectedBeforeLParen,
-      leftParen: lparen,
-      expression: expr,
-      unexpectedBeforeRParen,
-      rightParen: rparen,
-      arena: self.arena
-    )
-  }
 }
 
 // MARK: Throw Statements

Sources/SwiftParser/TokenPrecedence.swift

@@ -108,7 +108,7 @@ public enum TokenPrecedence: Comparable {
     case  // Literals
     .floatingLiteral, .integerLiteral, .regexLiteral,
       // Pound literals
-      .poundAvailableKeyword, .poundHasSymbolKeyword,
+      .poundAvailableKeyword,
       // Identifiers
       .dollarIdentifier, .identifier,
       // '_' can occur in types to replace a type identifier

gyb_syntax_support/Token.py

@@ -241,8 +241,6 @@ def macro_name(self):
     PoundConfig('PoundAvailable', 'available', text='#available'),
     PoundConfig('PoundUnavailable', 'unavailable', text='#unavailable'),
 
-    PoundConfig('PoundHasSymbol', '_hasSymbol', text='#_hasSymbol'),
-
     Literal('IntegerLiteral', 'integer_literal', name_for_diagnostics='integer literal',
             classification='IntegerLiteral'),
     Literal('FloatingLiteral', 'floating_literal',