[clang] Fix crash and improve diagnostics for void lambda returns (PR #188904)

[Kartik Ohlan via cfe-commits]

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@@ -18,7 +18,8 @@ void infer_void_return_type(int i) {
     switch (x) {
     case 0: return get<void>();
     case 1: return;
-    case 2: return { 1, 2.0 }; // expected-error {{cannot deduce lambda return type from initializer list}}
+    case 2: return { 1, 2.0 }; // expected-error {{cannot deduce lambda return type from initializer list}} \
+                                   // cxx11-error {{void lambda should not return a value}}
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Ko496-glitch wrote:

yeah sure, i just wanted to first get the brute force solution since it was passing on my  machine yesterday :( 

My first thought was that changing line 21 to newer diagnositc " void lambda should not return a value" would fix it but that wasn't the case 



https://github.com/llvm/llvm-project/pull/188904