[clang] [clang] Check constexpr int->enum conversions consistently. (PR #143034)

[Shafik Yaghmour via cfe-commits]

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@@ -2513,6 +2513,9 @@ void testValueInRangeOfEnumerationValues() {
   // expected-error at -1 {{constexpr variable 'x2' must be initialized by a constant expression}}
   // expected-note at -2 {{integer value 8 is outside the valid range of values [-8, 7] for the enumeration type 'E1'}}
   E1 x2b = static_cast<E1>(8); // ok, not a constant expression context
+  static_assert(static_cast<E1>(8), "");
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shafik wrote:

I guess these are the cases my previous checks missed?

https://github.com/llvm/llvm-project/pull/143034