libSyntax: create parameter list for function signatures without parameters.

If we don't create the empty parameter list, a 0-parameter function declaration
will not be well-formed.

Author: nkcsgexi

lib/Parse/ParsePattern.cpp

@@ -158,6 +158,10 @@ Parser::parseParameterClause(SourceLoc &leftParenLoc,
 
   // Trivial case: empty parameter list.
   if (Tok.is(tok::r_paren)) {
+    {
+      SyntaxParsingContext EmptyPLContext(SyntaxContext,
+                                          SyntaxKind::FunctionParameterList);
+    }
     rightParenLoc = consumeToken(tok::r_paren);
     return ParserStatus();
   }

test/Syntax/Outputs/round_trip_parse_gen.swift.withkinds

@@ -8,8 +8,8 @@ class C {<FunctionDecl>
   func bar1<FunctionSignature>(<FunctionParameter>_ a: <SimpleTypeIdentifier>Float</SimpleTypeIdentifier></FunctionParameter>) -> <SimpleTypeIdentifier>Float </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{ <ReturnStmt>return <SequenceExpr><PrefixOperatorExpr>-<FloatLiteralExpr>0.6 </FloatLiteralExpr></PrefixOperatorExpr><BinaryOperatorExpr>+ </BinaryOperatorExpr><FloatLiteralExpr>0.1 </FloatLiteralExpr><BinaryOperatorExpr>- </BinaryOperatorExpr><FloatLiteralExpr>0.3 </FloatLiteralExpr></SequenceExpr></ReturnStmt>}</CodeBlock></FunctionDecl><FunctionDecl>
   func bar2<FunctionSignature>(<FunctionParameter>a: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier>, </FunctionParameter><FunctionParameter>b: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier>, </FunctionParameter><FunctionParameter>c:<SimpleTypeIdentifier>Int</SimpleTypeIdentifier></FunctionParameter>) -> <SimpleTypeIdentifier>Int </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{ <ReturnStmt>return <IntegerLiteralExpr>1 </IntegerLiteralExpr></ReturnStmt>}</CodeBlock></FunctionDecl><FunctionDecl>
   func bar3<FunctionSignature>(<FunctionParameter>a: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier></FunctionParameter>) -> <SimpleTypeIdentifier>Int </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{ <ReturnStmt>return <IntegerLiteralExpr>1 </IntegerLiteralExpr></ReturnStmt>}</CodeBlock></FunctionDecl><FunctionDecl>
-  func bar4<FunctionSignature>(<FunctionParameter>_ a: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier></FunctionParameter>) -> <SimpleTypeIdentifier>Int </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{ <ReturnStmt>return <IntegerLiteralExpr>1 </IntegerLiteralExpr></ReturnStmt>}</CodeBlock></FunctionDecl>
-  func foo() <CodeBlock>{
+  func bar4<FunctionSignature>(<FunctionParameter>_ a: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier></FunctionParameter>) -> <SimpleTypeIdentifier>Int </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{ <ReturnStmt>return <IntegerLiteralExpr>1 </IntegerLiteralExpr></ReturnStmt>}</CodeBlock></FunctionDecl><FunctionDecl>
+  func foo<FunctionSignature>() </FunctionSignature><CodeBlock>{
     var a = <StringLiteralExpr>/*comment*/"ab\(x)c"</StringLiteralExpr>/*comment*/
     var b = <PrefixOperatorExpr>/*comment*/+<IntegerLiteralExpr>2</IntegerLiteralExpr></PrefixOperatorExpr><IdentifierExpr>/*comment*/
     bar</IdentifierExpr>(<FunctionCallArgument><IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>)<IdentifierExpr>
@@ -19,9 +19,9 @@ class C {<FunctionDecl>
     bar1</IdentifierExpr>(<FunctionCallArgument><FloatLiteralExpr>1.1</FloatLiteralExpr></FunctionCallArgument>)
     var f = <PrefixOperatorExpr>/*comments*/+<FloatLiteralExpr>0.1</FloatLiteralExpr></PrefixOperatorExpr><IdentifierExpr>/*comments*/
     foo</IdentifierExpr>()
-  }</CodeBlock>
+  }</CodeBlock></FunctionDecl><FunctionDecl>
 
-  func foo1() <CodeBlock>{<SequenceExpr><DiscardAssignmentExpr>
+  func foo1<FunctionSignature>() </FunctionSignature><CodeBlock>{<SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><IdentifierExpr>bar2</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr>, </FunctionCallArgument><FunctionCallArgument>b:<IntegerLiteralExpr>2</IntegerLiteralExpr>, </FunctionCallArgument><FunctionCallArgument>c:<IntegerLiteralExpr>2</IntegerLiteralExpr></FunctionCallArgument>)</SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><IdentifierExpr>bar2</IdentifierExpr>(<FunctionCallArgument>a:<SequenceExpr><IntegerLiteralExpr>1 </IntegerLiteralExpr><BinaryOperatorExpr>+ </BinaryOperatorExpr><IntegerLiteralExpr>1</IntegerLiteralExpr></SequenceExpr>, </FunctionCallArgument><FunctionCallArgument>b:<SequenceExpr><IntegerLiteralExpr>2 </IntegerLiteralExpr><BinaryOperatorExpr>* </BinaryOperatorExpr><IntegerLiteralExpr>2 </IntegerLiteralExpr><BinaryOperatorExpr>+ </BinaryOperatorExpr><IntegerLiteralExpr>2</IntegerLiteralExpr></SequenceExpr>, </FunctionCallArgument><FunctionCallArgument>c:<SequenceExpr><IntegerLiteralExpr>2 </IntegerLiteralExpr><BinaryOperatorExpr>+ </BinaryOperatorExpr><IntegerLiteralExpr>2</IntegerLiteralExpr></SequenceExpr></FunctionCallArgument>)</SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><IdentifierExpr>bar2</IdentifierExpr>(<FunctionCallArgument>a : <IdentifierExpr>bar2</IdentifierExpr>(<FunctionCallArgument>a: <IntegerLiteralExpr>1</IntegerLiteralExpr>, </FunctionCallArgument><FunctionCallArgument>b: <IntegerLiteralExpr>2</IntegerLiteralExpr>, </FunctionCallArgument><FunctionCallArgument>c: <IntegerLiteralExpr>3</IntegerLiteralExpr></FunctionCallArgument>), </FunctionCallArgument><FunctionCallArgument>b: <IntegerLiteralExpr>2</IntegerLiteralExpr>, </FunctionCallArgument><FunctionCallArgument>c: <IntegerLiteralExpr>3</IntegerLiteralExpr></FunctionCallArgument>)</SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
@@ -32,11 +32,11 @@ class C {<FunctionDecl>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><ArrayExpr>[<ArrayElement><IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>), </ArrayElement><ArrayElement><IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>), </ArrayElement><ArrayElement><IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>), </ArrayElement><ArrayElement><IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>)</ArrayElement>]</ArrayExpr></SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><DictionaryExpr>[<DictionaryElement><StringLiteralExpr>"a"</StringLiteralExpr>: <IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>), </DictionaryElement><DictionaryElement><StringLiteralExpr>"b"</StringLiteralExpr>: <IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>), </DictionaryElement><DictionaryElement><StringLiteralExpr>"c"</StringLiteralExpr>: <IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>), </DictionaryElement><DictionaryElement><StringLiteralExpr>"d"</StringLiteralExpr>: <IdentifierExpr>bar3</IdentifierExpr>(<FunctionCallArgument>a:<IntegerLiteralExpr>1</IntegerLiteralExpr></FunctionCallArgument>)</DictionaryElement>]</DictionaryExpr></SequenceExpr><IdentifierExpr>
     foo</IdentifierExpr>(<FunctionCallArgument><NilLiteralExpr>nil</NilLiteralExpr>, </FunctionCallArgument><FunctionCallArgument><NilLiteralExpr>nil</NilLiteralExpr>, </FunctionCallArgument><FunctionCallArgument><NilLiteralExpr>nil</NilLiteralExpr></FunctionCallArgument>)
-  }</CodeBlock>
-  func boolAnd() -> <SimpleTypeIdentifier>Bool </SimpleTypeIdentifier><CodeBlock>{ <ReturnStmt>return <SequenceExpr><BooleanLiteralExpr>true </BooleanLiteralExpr><BinaryOperatorExpr>&& </BinaryOperatorExpr><BooleanLiteralExpr>false </BooleanLiteralExpr></SequenceExpr></ReturnStmt>}</CodeBlock>
-  func boolOr() -> <SimpleTypeIdentifier>Bool </SimpleTypeIdentifier><CodeBlock>{ <ReturnStmt>return <SequenceExpr><BooleanLiteralExpr>true </BooleanLiteralExpr><BinaryOperatorExpr>|| </BinaryOperatorExpr><BooleanLiteralExpr>false </BooleanLiteralExpr></SequenceExpr></ReturnStmt>}</CodeBlock>
+  }</CodeBlock></FunctionDecl><FunctionDecl>
+  func boolAnd<FunctionSignature>() -> <SimpleTypeIdentifier>Bool </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{ <ReturnStmt>return <SequenceExpr><BooleanLiteralExpr>true </BooleanLiteralExpr><BinaryOperatorExpr>&& </BinaryOperatorExpr><BooleanLiteralExpr>false </BooleanLiteralExpr></SequenceExpr></ReturnStmt>}</CodeBlock></FunctionDecl><FunctionDecl>
+  func boolOr<FunctionSignature>() -> <SimpleTypeIdentifier>Bool </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{ <ReturnStmt>return <SequenceExpr><BooleanLiteralExpr>true </BooleanLiteralExpr><BinaryOperatorExpr>|| </BinaryOperatorExpr><BooleanLiteralExpr>false </BooleanLiteralExpr></SequenceExpr></ReturnStmt>}</CodeBlock></FunctionDecl><FunctionDecl>
 
-  func foo2() <CodeBlock>{<SequenceExpr><DiscardAssignmentExpr>
+  func foo2<FunctionSignature>() </FunctionSignature><CodeBlock>{<SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><TernaryExpr><BooleanLiteralExpr>true </BooleanLiteralExpr>? <IntegerLiteralExpr>1 </IntegerLiteralExpr>: <IntegerLiteralExpr>0</IntegerLiteralExpr></TernaryExpr></SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><TernaryExpr><TupleExpr>(<TupleElement><SequenceExpr><TernaryExpr><BooleanLiteralExpr>true </BooleanLiteralExpr>? <IntegerLiteralExpr>1 </IntegerLiteralExpr>: <IntegerLiteralExpr>0</IntegerLiteralExpr></TernaryExpr></SequenceExpr></TupleElement>) </TupleExpr>? <TupleExpr>(<TupleElement><SequenceExpr><TernaryExpr><BooleanLiteralExpr>true </BooleanLiteralExpr>? <IntegerLiteralExpr>1 </IntegerLiteralExpr>: <IntegerLiteralExpr>0</IntegerLiteralExpr></TernaryExpr></SequenceExpr></TupleElement>) </TupleExpr>: <TupleExpr>(<TupleElement><SequenceExpr><TernaryExpr><BooleanLiteralExpr>true </BooleanLiteralExpr>? <IntegerLiteralExpr>1 </IntegerLiteralExpr>: <IntegerLiteralExpr>0</IntegerLiteralExpr></TernaryExpr></SequenceExpr></TupleElement>)</TupleExpr></TernaryExpr></SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><TupleExpr>(<TupleElement><IntegerLiteralExpr>1</IntegerLiteralExpr>, </TupleElement><TupleElement><IntegerLiteralExpr>2</IntegerLiteralExpr></TupleElement>)</TupleExpr></SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
@@ -46,17 +46,17 @@ class C {<FunctionDecl>
     if <PrefixOperatorExpr>!<BooleanLiteralExpr>true </BooleanLiteralExpr></PrefixOperatorExpr><CodeBlock>{<ReturnStmt>
       return</ReturnStmt>
     }</CodeBlock>
-  }</CodeBlock>
+  }</CodeBlock></FunctionDecl><FunctionDecl>
 
-  func foo3() <CodeBlock>{<SequenceExpr><DiscardAssignmentExpr>
+  func foo3<FunctionSignature>() </FunctionSignature><CodeBlock>{<SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><ArrayExpr>[<ArrayElement><TypeExpr><SimpleTypeIdentifier>Any</SimpleTypeIdentifier></TypeExpr></ArrayElement>]</ArrayExpr>()</SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><MemberAccessExpr><MemberAccessExpr><IdentifierExpr>a</IdentifierExpr>.a</MemberAccessExpr>.a</MemberAccessExpr></SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><MemberAccessExpr><IdentifierExpr>a</IdentifierExpr>.b</MemberAccessExpr></SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><MemberAccessExpr><IntegerLiteralExpr>1</IntegerLiteralExpr>.a</MemberAccessExpr></SequenceExpr><MemberAccessExpr><MemberAccessExpr><MemberAccessExpr><TupleExpr>
     (<TupleElement><SequenceExpr><IntegerLiteralExpr>1 </IntegerLiteralExpr><BinaryOperatorExpr>+ </BinaryOperatorExpr><IntegerLiteralExpr>1</IntegerLiteralExpr></SequenceExpr></TupleElement>)</TupleExpr>.a</MemberAccessExpr>.b</MemberAccessExpr>.foo</MemberAccessExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><IdentifierExpr>a </IdentifierExpr><AsExpr>as <SimpleTypeIdentifier>Bool </SimpleTypeIdentifier></AsExpr><BinaryOperatorExpr>|| </BinaryOperatorExpr><IdentifierExpr>a </IdentifierExpr><AsExpr>as! <SimpleTypeIdentifier>Bool </SimpleTypeIdentifier></AsExpr><BinaryOperatorExpr>|| </BinaryOperatorExpr><IdentifierExpr>a </IdentifierExpr><AsExpr>as? <SimpleTypeIdentifier>Bool</SimpleTypeIdentifier></AsExpr></SequenceExpr><SequenceExpr><DiscardAssignmentExpr>
     _ </DiscardAssignmentExpr><AssignmentExpr>= </AssignmentExpr><IdentifierExpr>a </IdentifierExpr><IsExpr>is <SimpleTypeIdentifier>Bool</SimpleTypeIdentifier></IsExpr></SequenceExpr>
-  }</CodeBlock>
+  }</CodeBlock></FunctionDecl>
 }
 
 typealias A = <SimpleTypeIdentifier>Any</SimpleTypeIdentifier>
@@ -68,9 +68,9 @@ typealias F = <MetatypeType><ImplicitlyUnwrappedOptionalType><ArrayType>[<Simple
 
 struct foo <MemberDeclBlock>{<StructDecl>
   struct foo <MemberDeclBlock>{<StructDecl>
-    struct foo <MemberDeclBlock>{
-      func foo() <CodeBlock>{
-      }</CodeBlock>
+    struct foo <MemberDeclBlock>{<FunctionDecl>
+      func foo<FunctionSignature>() </FunctionSignature><CodeBlock>{
+      }</CodeBlock></FunctionDecl>
     }</MemberDeclBlock></StructDecl>
   }</MemberDeclBlock></StructDecl><StructDecl>
   struct foo <MemberDeclBlock>{}</MemberDeclBlock></StructDecl>
@@ -79,10 +79,10 @@ struct foo <MemberDeclBlock>{<StructDecl>
 struct foo <MemberDeclBlock>{<StructDecl><Attribute>
   @available(*, unavailable)</Attribute>
   struct foo <MemberDeclBlock>{}</MemberDeclBlock></StructDecl><DeclModifier>
-  public </DeclModifier>class foo {<Attribute>
+  public </DeclModifier>class foo {<FunctionDecl><Attribute>
     @available(*, unavailable)</Attribute><Attribute>
     @objc(fooObjc)</Attribute><DeclModifier>
-    private </DeclModifier><DeclModifier>static </DeclModifier>func foo() <CodeBlock>{}</CodeBlock>
+    private </DeclModifier><DeclModifier>static </DeclModifier>func foo<FunctionSignature>() </FunctionSignature><CodeBlock>{}</CodeBlock></FunctionDecl>
   }
 }</MemberDeclBlock></StructDecl><StructDecl>
 
@@ -108,5 +108,6 @@ func foo<FunctionSignature>( <FunctionParameter>a: <SimpleTypeIdentifier>Int</Si
 struct C <MemberDeclBlock>{<FunctionDecl><Attribute>
 @objc</Attribute><Attribute>
 @available(*, unavailable)</Attribute><DeclModifier>
-private </DeclModifier><DeclModifier>static </DeclModifier><DeclModifier>override </DeclModifier>func foo<GenericParameterClause><<GenericParameter>a, </GenericParameter><GenericParameter>b, </GenericParameter><GenericParameter>c</GenericParameter>></GenericParameterClause><FunctionSignature>(<FunctionParameter>a b: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier>, </FunctionParameter><FunctionParameter>c: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier></FunctionParameter>) throws -> <ArrayType>[<SimpleTypeIdentifier>Int</SimpleTypeIdentifier>] </ArrayType></FunctionSignature><GenericWhereClause>where <SameTypeRequirement><SimpleTypeIdentifier>a</SimpleTypeIdentifier>==<SimpleTypeIdentifier>p1</SimpleTypeIdentifier>, </SameTypeRequirement><ConformanceRequirement><SimpleTypeIdentifier>b</SimpleTypeIdentifier>:<SimpleTypeIdentifier>p2 </SimpleTypeIdentifier></ConformanceRequirement></GenericWhereClause><CodeBlock>{ <IdentifierExpr>ddd </IdentifierExpr>}</CodeBlock></FunctionDecl>
+private </DeclModifier><DeclModifier>static </DeclModifier><DeclModifier>override </DeclModifier>func foo<GenericParameterClause><<GenericParameter>a, </GenericParameter><GenericParameter>b, </GenericParameter><GenericParameter>c</GenericParameter>></GenericParameterClause><FunctionSignature>(<FunctionParameter>a b: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier>, </FunctionParameter><FunctionParameter>c: <SimpleTypeIdentifier>Int</SimpleTypeIdentifier></FunctionParameter>) throws -> <ArrayType>[<SimpleTypeIdentifier>Int</SimpleTypeIdentifier>] </ArrayType></FunctionSignature><GenericWhereClause>where <SameTypeRequirement><SimpleTypeIdentifier>a</SimpleTypeIdentifier>==<SimpleTypeIdentifier>p1</SimpleTypeIdentifier>, </SameTypeRequirement><ConformanceRequirement><SimpleTypeIdentifier>b</SimpleTypeIdentifier>:<SimpleTypeIdentifier>p2 </SimpleTypeIdentifier></ConformanceRequirement></GenericWhereClause><CodeBlock>{ <IdentifierExpr>ddd </IdentifierExpr>}</CodeBlock></FunctionDecl><FunctionDecl>
+func rootView<FunctionSignature>() -> <SimpleTypeIdentifier>Label </SimpleTypeIdentifier></FunctionSignature><CodeBlock>{}</CodeBlock></FunctionDecl>
 }</MemberDeclBlock></StructDecl>

test/Syntax/round_trip_parse_gen.swift

@@ -109,4 +109,5 @@ struct C {
 @objc
 @available(*, unavailable)
 private static override func foo<a, b, c>(a b: Int, c: Int) throws -> [Int] where a==p1, b:p2 { ddd }
+func rootView() -> Label {}
 }