[clang] [Serialization] Handle uninitialized type constraints (PR #110496)

[via cfe-commits]

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@@ -2674,7 +2674,7 @@ void ASTDeclReader::VisitTemplateTypeParmDecl(TemplateTypeParmDecl *D) {
 
   D->setDeclaredWithTypename(Record.readInt());
 
-  if (D->hasTypeConstraint()) {
+  if (Record.readBool() && D->hasTypeConstraint()) {
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cor3ntin wrote:

Can you put that bool in a variable? It would be more clear what it is

https://github.com/llvm/llvm-project/pull/110496