[clang] [-Wunterminated-string-initialization] Handle C string literals ending with explicit '\0' (PR #143487)

[Aaron Ballman via cfe-commits]

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@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunterminated-string-initialization %s -x c
+// RUN: %clang_cc1 -fsyntax-only -verify -Wunterminated-string-initialization %s -x c++
+
+
+// In C, the following examples are fine:
+#if __cplusplus
+char foo[3] = "fo\0"; // expected-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
+
+struct S {
+  char buf[3];
+  char fub[3];
+} s = { "ba\0", "bo\0" }; // expected-error 2{{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
+
+signed char scfoo[3] = "fo\0"; // expected-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
+unsigned char ucfoo[3] = "fo\0"; // expected-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
+
----------------
AaronBallman wrote:

Another test case that's good to add would be:
```
char c[1] = ""; // Okay
```


https://github.com/llvm/llvm-project/pull/143487