Accept 'T...[]' within a function parameter scope

Author: zyn0217

clang/lib/Parse/ParseExprCXX.cpp

@@ -238,7 +238,8 @@ bool Parser::ParseOptionalCXXScopeSpecifier(
 
   else if (!HasScopeSpecifier && Tok.is(tok::identifier) &&
            GetLookAheadToken(1).is(tok::ellipsis) &&
-           GetLookAheadToken(2).is(tok::l_square)) {
+           GetLookAheadToken(2).is(tok::l_square) &&
+           !GetLookAheadToken(3).is(tok::r_square)) {
     SourceLocation Start = Tok.getLocation();
     DeclSpec DS(AttrFactory);
     SourceLocation CCLoc;

clang/test/CXX/dcl.decl/dcl.meaning/dcl.fct/p13.cpp

@@ -57,10 +57,11 @@ template<typename T>
 void b(T[] ...);
 
 template<typename T>
-void c(T ... []); // expected-error {{expected expression}} \
-                  // expected-error {{type 'T[]' of function parameter pack does not contain any unexpanded parameter packs}} \
-                  // expected-warning {{would become a pack indexing declaration in C++2c onwards}} \
-                  // expected-note {{add a name to disambiguate}}
+void c(T ... []); // expected-error {{type 'T[]' of function parameter pack does not contain any unexpanded parameter packs}}
+
+// A function that takes pointers to each type T as arguments, after any decay.
+template <typename ...T>
+void g(T...[]);
 
 template<typename T>
 void d(T ... x[]); // expected-error{{type 'T[]' of function parameter pack does not contain any unexpanded parameter packs}}

clang/test/Parser/cxx2c-pack-indexing.cpp

@@ -12,8 +12,7 @@ struct S {
             // expected-note {{to match this '['}} \
            // expected-warning{{declaration does not declare anything}}
 
-    T...[]; // expected-error{{expected expression}} \
-           // expected-warning{{declaration does not declare anything}}
+    T...[]; // expected-error{{expected member name or ';' after declaration specifiers}}
 
     void f(auto... v) {
         decltype(v...[1]) a = v...[1];
@@ -65,7 +64,7 @@ int main() {
 }
 
 
-namespace GH11460 {
+namespace GH111460 {
 template <typename... T>
 requires( ); // expected-error {{expected expression}}
 struct SS {