[clang] [Clang] Substitute non dependent concepts in constraints (PR #163827)

[Younan Zhang via cfe-commits]

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@@ -2249,8 +2287,14 @@ NormalizedConstraint *NormalizedConstraint::fromConstraintExpr(
       // Use canonical declarations to merge ConceptDecls across
       // different modules.
       ConceptDecl *CD = CSE->getNamedConcept()->getCanonicalDecl();
+
+      ExprResult Res =
+          SubstituteConceptsInConstrainExpression(S, D, CSE, SubstIndex);
+      if (!Res.isUsable())
+        return nullptr;
+
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zyn0217 wrote:

Note that a substitution in this function will risk resulting in an exponential time complexity, unless we can ensure that the substitution in SubstituteConceptsInConstrainExpression is not deeply recursive. (i.e. at most 1 level substitution)

https://github.com/llvm/llvm-project/pull/163827