Merge pull request #25837 from rintaro/5.1-syntax-identpattern-self-rdar52285009

[5.1][Syntax] Accept 'self' as IdentifierPatternSyntax

Author: rintaro

test/Syntax/Outputs/round_trip_parse_gen.swift.withkinds

@@ -368,7 +368,9 @@ func statementTests<FunctionSignature><ParameterClause>() </ParameterClause></Fu
   } </CodeBlock>else <CodeBlock>{
   }</CodeBlock></IfStmt></IfStmt><GuardStmt>
 
-  guard <ConditionElement><OptionalBindingCondition>let <IdentifierPattern>a </IdentifierPattern><InitializerClause>= <IdentifierExpr>b </IdentifierExpr></InitializerClause></OptionalBindingCondition></ConditionElement>else <CodeBlock>{}</CodeBlock></GuardStmt><ForInStmt>
+  guard <ConditionElement><OptionalBindingCondition>let <IdentifierPattern>a </IdentifierPattern><InitializerClause>= <IdentifierExpr>b </IdentifierExpr></InitializerClause></OptionalBindingCondition></ConditionElement>else <CodeBlock>{}</CodeBlock></GuardStmt><GuardStmt>
+
+  guard <ConditionElement><OptionalBindingCondition>let <IdentifierPattern>self </IdentifierPattern><InitializerClause>= <IdentifierExpr>self </IdentifierExpr></InitializerClause></OptionalBindingCondition></ConditionElement>else <CodeBlock>{}</CodeBlock></GuardStmt><ForInStmt>
 
   for <ValueBindingPattern>var <IdentifierPattern>i </IdentifierPattern></ValueBindingPattern>in <IdentifierExpr>foo </IdentifierExpr><WhereClause>where <MemberAccessExpr><IdentifierExpr>i</IdentifierExpr>.foo </MemberAccessExpr></WhereClause><CodeBlock>{}</CodeBlock></ForInStmt><ForInStmt>
   for case <IsTypePattern>is <SimpleTypeIdentifier>Int </SimpleTypeIdentifier></IsTypePattern>in <IdentifierExpr>foo </IdentifierExpr><CodeBlock>{}</CodeBlock></ForInStmt><SwitchStmt>

test/Syntax/round_trip_parse_gen.swift

@@ -370,6 +370,8 @@ func statementTests() {
 
   guard let a = b else {}
 
+  guard let self = self else {}
+
   for var i in foo where i.foo {}
   for case is Int in foo {}
 

utils/gyb_syntax_support/PatternNodes.py

@@ -38,7 +38,11 @@
     # identifier-pattern -> identifier
     Node('IdentifierPattern', kind='Pattern',
          children=[
-             Child('Identifier', kind='IdentifierToken')
+             Child('Identifier', kind='Token',
+                   token_choices=[
+                       'SelfToken',
+                       'IdentifierToken',
+                   ]),
          ]),
 
     # as-pattern -> pattern 'as' type