[clang]Treat arguments to builtin type traits as template type arguments (#87132)

This change improves error messages for builtins in case of empty
parentheses.

Fixes #86997

Author: AMP999

clang/lib/Parse/ParseExprCXX.cpp

@@ -3910,10 +3910,10 @@ ExprResult Parser::ParseTypeTrait() {
   SmallVector<ParsedType, 2> Args;
   do {
     // Parse the next type.
-    TypeResult Ty =
-        ParseTypeName(/*SourceRange=*/nullptr,
-                      getLangOpts().CPlusPlus ? DeclaratorContext::TemplateArg
-                                              : DeclaratorContext::TypeName);
+    TypeResult Ty = ParseTypeName(/*SourceRange=*/nullptr,
+                                  getLangOpts().CPlusPlus
+                                      ? DeclaratorContext::TemplateTypeArg
+                                      : DeclaratorContext::TypeName);
     if (Ty.isInvalid()) {
       Parens.skipToEnd();
       return ExprError();
@@ -3955,8 +3955,8 @@ ExprResult Parser::ParseArrayTypeTrait() {
   if (T.expectAndConsume())
     return ExprError();
 
-  TypeResult Ty =
-      ParseTypeName(/*SourceRange=*/nullptr, DeclaratorContext::TemplateArg);
+  TypeResult Ty = ParseTypeName(/*SourceRange=*/nullptr,
+                                DeclaratorContext::TemplateTypeArg);
   if (Ty.isInvalid()) {
     SkipUntil(tok::comma, StopAtSemi);
     SkipUntil(tok::r_paren, StopAtSemi);

clang/test/Sema/static-assert.c

@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -std=c11 -Wgnu-folding-constant -fsyntax-only -verify=expected,c %s
-// RUN: %clang_cc1 -fms-compatibility -Wgnu-folding-constant -DMS -fsyntax-only -verify=expected,ms,c %s
-// RUN: %clang_cc1 -std=c99 -pedantic -Wgnu-folding-constant -fsyntax-only -verify=expected,ext,c %s
+// RUN: %clang_cc1 -std=c11 -Wgnu-folding-constant -fsyntax-only -verify %s
+// RUN: %clang_cc1 -fms-compatibility -Wgnu-folding-constant -DMS -fsyntax-only -verify=expected,ms %s
+// RUN: %clang_cc1 -std=c99 -pedantic -Wgnu-folding-constant -fsyntax-only -verify=expected,ext %s
 // RUN: %clang_cc1 -xc++ -std=c++11 -pedantic -fsyntax-only -verify=expected,ext,cxx %s
 
 _Static_assert("foo", "string is nonzero"); // ext-warning {{'_Static_assert' is a C11 extension}}
@@ -57,8 +57,7 @@ UNION(char[2], short) u2 = { .one = { 'a', 'b' } }; // ext-warning 3 {{'_Static_
 typedef UNION(char, short) U3; // expected-error {{static assertion failed due to requirement 'sizeof(char) == sizeof(short)': type size mismatch}} \
                                // expected-note{{evaluates to '1 == 2'}} \
                                // ext-warning 3 {{'_Static_assert' is a C11 extension}}
-typedef UNION(float, 0.5f) U4; // c-error {{expected a type}} \
-                               // cxx-error {{type name requires a specifier or qualifier}} \
+typedef UNION(float, 0.5f) U4; // expected-error {{expected a type}} \
                                // ext-warning 3 {{'_Static_assert' is a C11 extension}}
 
 // After defining the assert macro in MS-compatibility mode, we should

clang/test/SemaCXX/builtins.cpp

@@ -76,6 +76,11 @@ using ConstMemFnType = int (Dummy::*)() const;
 
 void foo() {}
 
+void test_builtin_empty_parentheses_diags() {
+  __is_trivially_copyable(); // expected-error {{expected a type}}
+  __is_trivially_copyable(1); // expected-error {{expected a type}}
+}
+
 void test_builtin_launder_diags(void *vp, const void *cvp, FnType *fnp,
                                 MemFnType mfp, ConstMemFnType cmfp, int (&Arr)[5]) {
   __builtin_launder(vp);   // expected-error {{void pointer argument to '__builtin_launder' is not allowed}}

clang/test/SemaCXX/deprecated-builtins.cpp

@@ -17,3 +17,8 @@ void f() {
     a = __has_trivial_destructor(A);  // expected-warning-re {{__has_trivial_destructor {{.*}} use __is_trivially_destructible}}
 
 }
+
+void test_builtin_empty_parentheses_diags(void) {
+    __has_nothrow_copy(); // expected-error {{expected a type}}
+    __has_nothrow_copy(1); // expected-error {{expected a type}}
+}