[clang] [HLSL][RootSignature] Use "stringified" version for diagnostic output of punctuator tokens (PR #145827)

[Ashley Coleman via cfe-commits]

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@@ -18,3 +18,7 @@ void bad_root_signature_3() {}
 
 [RootSignature("DescriptorTable(), invalid")] // expected-error {{expected end of stream to denote end of parameters, or, another valid parameter of RootSignature}}
 void bad_root_signature_4() {}
+
+// expected-error at +1 {{expected ')' to denote end of parameters, or, another valid parameter of RootConstants}}
+[RootSignature("RootConstants(b0, num32BitConstants = 1, invalid)")]
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V-FEXrt wrote:

Am I missing a detail here? The parens are matched in this test case right? If so this error message would send me down a very wrong path.

Maybe that is because I'm not familiar with rootsigs, maybe someone more familiar with them would understand the error better

https://github.com/llvm/llvm-project/pull/145827