From: Martin Uecker <uecker@tugraz.at>
Date: Fri, 9 Jan 2026 13:38:31 +0000 (+0100)
Subject: c: Fix ignored qualifier issue for enumerations [PR123435,PR123463]
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=00b6346d5374efab8dabbf99d2647ad69b1df706;p=thirdparty%2Fgcc.git

c: Fix ignored qualifier issue for enumerations [PR123435,PR123463]

We accept a mismatch in qualifiers for enumerations and integers
because we switch to the underlying type before checking that qualifiers
match.

	PR c/123435
	PR c/123463

gcc/c/ChangeLog:
	* c-typeck.cc (comptypes_internal): Test for qualifiers first.

gcc/testsuite/ChangeLog:
	* gcc.dg/pr123435-1.c: New test.
	* gcc.dg/pr123435-2.c: New test.
	* gcc.dg/pr123463.c: New test.
---

diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index 43d4a5d5d9e..a762f3c47d1 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -1666,6 +1666,11 @@ comptypes_internal (const_tree type1, const_tree type2,
       || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
     return true;
 
+  /* Qualifiers must match. C99 6.7.3p9 */
+
+  if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
+    return false;
+
   /* Enumerated types are compatible with integer types, but this is
      not transitive: two enumerated types in the same translation unit
      are compatible with each other only if they are the same type.  */
@@ -1701,11 +1706,6 @@ comptypes_internal (const_tree type1, const_tree type2,
   if (TREE_CODE (t1) != TREE_CODE (t2))
     return false;
 
-  /* Qualifiers must match. C99 6.7.3p9 */
-
-  if (TYPE_QUALS (t1) != TYPE_QUALS (t2))
-    return false;
-
   /* Allow for two different type nodes which have essentially the same
      definition.  Note that we already checked for equality of the type
      qualifiers (just above).  */
diff --git a/gcc/testsuite/gcc.dg/pr123435-1.c b/gcc/testsuite/gcc.dg/pr123435-1.c
new file mode 100644
index 00000000000..18d579ee112
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr123435-1.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c23" } */
+
+const enum E { A } *x;
+
+/* qualifier mismatch */
+_Static_assert(_Generic(x, unsigned int *: 0, default: 1), "");
+
diff --git a/gcc/testsuite/gcc.dg/pr123435-2.c b/gcc/testsuite/gcc.dg/pr123435-2.c
new file mode 100644
index 00000000000..7ad605cccc5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr123435-2.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+
+enum E { E1 = -1, E2 = 0, E3 = 1 };
+const volatile enum E i2;
+extern int i2;			/* { dg-error "conflicting type qualifiers" } */
+
diff --git a/gcc/testsuite/gcc.dg/pr123463.c b/gcc/testsuite/gcc.dg/pr123463.c
new file mode 100644
index 00000000000..1ae445aed41
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr123463.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+
+enum mm { L };
+extern const enum mm m[1];
+void f(unsigned egno) {
+	f(m);		/* { dg-error "integer from pointer" } */
+}
+