[clang] [Clang] Do not perform integral promotion if operands of expression `x ? : y` have the same type (PR #108837)

[Shafik Yaghmour via cfe-commits]

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@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
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shafik wrote:

I think this test should go in `clang/test/Sema/conditional-expr.c` and we should add a section of the GNU extension there.

I am also a bit concerned that we don't have a specific set of sema tests for the GNU form of the conditional expression. So it makes me much left confident that we will catch any breaks with this change. 

https://github.com/llvm/llvm-project/pull/108837