[clang] [Clang] FunctionEffects: Correctly navigate through array types in FunctionEffectsRef::get(). (PR #121525)

[via cfe-commits]

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@@ -246,6 +246,26 @@ void PTMFTester::convert() [[clang::nonblocking]]
 	(this->*mConvertFunc)();
 }
 
+// Allow implicit conversion from array to pointer.
+void nb14(unsigned idx) [[clang::nonblocking]]
+{
+	using FP = void (*)() [[clang::nonblocking]];
+	using FPArray = FP[2];
+	auto nb = +[]() [[clang::nonblocking]] {};
+
+	FPArray src{ nb, nullptr };
+	FP f = src[idx]; // This should not generate a warning.
+
+	FP twoDim[2][2] = {};
+	FP g = twoDim[1][1];
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wvla-extension"
+	FP vla[idx];
+#pragma clang diagnostic pop
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Sirraide wrote:

I think it’s fine to either just throw `-Wno-vla-extension` into the `RUN` line or to add `expected-` directives for this and the notes it produces. We generally try to avoid disabling and then reenabling warnings with `#pragma`s in tests because that just ends up being a bit hard to follow...

https://github.com/llvm/llvm-project/pull/121525