[clang] [Clang] Guard against null in template instantiation process (PR #97913)

[via cfe-commits]

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@@ -636,6 +636,9 @@ bool Sema::SetupConstraintScope(
             ? FD->getInstantiatedFromMemberFunction()
             : FD->getInstantiatedFromDecl();
 
+    if (!InstantiatedFrom)
+      return true;
+
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smanna12 wrote:

Thank you @zyn0217 for the reviews and clarification. Closing this as Not a defect.

https://github.com/llvm/llvm-project/pull/97913