[clang] [Clang][Sema] Fix missing warning when comparing mismatched enums in … (PR #81418)

[Shafik Yaghmour via cfe-commits]

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@@ -0,0 +1,42 @@
+// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wenum-compare -Wno-unused-comparison %s
+// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wenum-compare -Wno-unused-comparison %s
+
+typedef enum EnumA {
+  A
+} EnumA;
+
+enum EnumB {
+  B
+};
+
+enum {
+  C
+};
+
+void foo(void) {
+  enum EnumA a = A;
+  enum EnumB b = B;
+  A == B;
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  a == (B);
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  a == b;
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  A > B;
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  A >= b;
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  a > b;
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  (A) <= ((B));
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  a < B;
+  // expected-warning at -1 {{comparison of different enumeration types}}
+  a < b;
+  // expected-warning at -1 {{comparison of different enumeration types}}
+
+  // In the following cases we purposefully differ from GCC and dont warn 
+  a == C; 
+  A < C;
+  b >= C; 
+}
----------------
shafik wrote:

Please add a newline at the end of the file

https://github.com/llvm/llvm-project/pull/81418