[clang] move -Wcast-function-type under -Wextra (llvm#77178)

The -Wcast-fuction-type-strict has been moved under dignstic group
-Wextra.
Edited the test cases for -Wcast-fuction-type-strict and
-Wcast-fuction-type in Sema an SemaCXX.

Added a new test case which include a functionality that was already in
the -Wextra group, i.e -Wignored-qualifiers with
-Wcast-fuction-type-strict.

Fixes: llvm#76872

clang/docs/ReleaseNotes.rst

@@ -193,6 +193,8 @@ Modified Compiler Flags
   ``-Wreturn-type``, and moved some of the diagnostics previously controlled by
   ``-Wreturn-type`` under this new flag. Fixes #GH72116.
 
+- Added ``-Wcast-function-type`` as a warning enabled by ``-Wextra``. #GH76872
+
 Removed Compiler Flags
 -------------------------
 

clang/include/clang/Basic/DiagnosticGroups.td

@@ -1038,6 +1038,7 @@ def Extra : DiagGroup<"extra", [
     EmptyInitStatement,
     StringConcatation,
     FUseLdPath,
+    CastFunctionType,
   ]>;
 
 def Most : DiagGroup<"most", [

clang/test/Sema/warn-cast-function-type-strict.c

@@ -1,6 +1,6 @@
 // RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type -verify
 // RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type-strict -verify
-
+// RUN: %clang_cc1 %s -fsyntax-only -Wextra -Wno-ignored-qualifiers -verify
 
 int t(int array[static 12]);
 int u(int i);
@@ -39,5 +39,6 @@ void foo(void) {
   g = (f7 *)x; /* expected-warning {{cast from 'int (*)(long)' to 'f7 *' (aka 'int (*)(long, ...)') converts to incompatible function type}} */
   h = (f8 *)t;
   i = (f9 *)u;
+  // FIXME: return type qualifier should not be included in the function type . Warning should be absent after this issue is fixed. https://github.com/llvm/llvm-project/issues/39494 .
   j = (f10 *)v; /* expected-warning {{cast from 'const int (*)(int)' to 'f10 *' (aka 'int (*)(int)') converts to incompatible function type}} */
 }

clang/test/Sema/warn-cast-function-type.c

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 %s -fsyntax-only -Wcast-function-type -Wno-cast-function-type-strict -verify
+// RUN: %clang_cc1 %s -fsyntax-only -Wextra -Wno-cast-function-type-strict -verify
 
 int x(long);
 

clang/test/SemaCXX/warn-cast-function-type-strict.cpp

@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wcast-function-type -verify
 // RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wcast-function-type-strict -verify
+// RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wextra -verify
 
 int x(long);
 

clang/test/SemaCXX/warn-cast-function-type.cpp

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wcast-function-type -Wno-cast-function-type-strict -verify
+// RUN: %clang_cc1 %s -fblocks -fsyntax-only -Wextra -Wno-cast-function-type-strict -verify
 
 int x(long);