[clang] [analyzer] CStringChecker: fix crash in `CheckOverlap` when arguments are not pointers (PR #160511)

[Donát Nagy via cfe-commits]

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@@ -96,3 +96,19 @@ void test_snprintf6() {
   char b[4] = {0};
   snprintf(a, sizeof(a), "%s", b); // no-warning
 }
+
+
+void memcpy(int dst, int src, size_t size); // expected-warning{{incompatible redeclaration of library function 'memcpy'}} expected-note{{'memcpy' is a builtin with type 'void *(void *, const void *, __size_t)' (aka 'void *(void *, const void *, unsigned long)')}}
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NagyDonat wrote:

The static analyzer tests usually add `-Wno-...` to the `RUN:` lines in order to silence the compiler warnings that overlap with the tested feature. I think that would be slightly more elegant here than these long `expected` lines.

https://github.com/llvm/llvm-project/pull/160511