[clang] [Clang] Fix crash on template-specialization (PR #142338)

[Timm Baeder via cfe-commits]

================
@@ -5120,6 +5121,10 @@ bool Sema::addInstantiatedParametersToScope(
       // Simple case: not a parameter pack.
       assert(FParamIdx < Function->getNumParams());
       ParmVarDecl *FunctionParam = Function->getParamDecl(FParamIdx);
+      DeclarationName name = FunctionParam->getDeclName();
----------------
tbaederr wrote:

```suggestion
      DeclarationName Name = FunctionParam->getDeclName();
```

https://github.com/llvm/llvm-project/pull/142338