[clang] [DiagnosticInfo] Allow std::string_view in DiagnosticBuilder operator<<. (PR #190374)

[Jackson Stogel via cfe-commits]

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@@ -164,20 +176,20 @@ TEST(DiagnosticTest, diagnosticError) {
   EXPECT_EQ(Value->first, 20);
 }
 
+class CaptureDiagnosticConsumer : public DiagnosticConsumer {
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jtstogel wrote:

Moved out of a function scope that it can be shared by `reportAcceptsStringViewMessage`

https://github.com/llvm/llvm-project/pull/190374