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

[Younan Zhang via cfe-commits]

================
@@ -4487,6 +4487,109 @@ ExprResult Sema::SubstConstraintExprWithoutSatisfaction(
   return Instantiator.TransformExpr(E);
 }
 
+ExprResult Sema::SubstConceptTemplateArguments(
+    const ConceptSpecializationExpr *CSE, const Expr *ConstraintExpr,
+    const MultiLevelTemplateArgumentList &MLTAL) {
+  TemplateInstantiator Instantiator(*this, MLTAL, SourceLocation(),
+                                    DeclarationName());
+  auto *ArgsAsWritten = CSE->getTemplateArgsAsWritten();
+  TemplateArgumentListInfo SubstArgs(ArgsAsWritten->getLAngleLoc(),
+                                     ArgsAsWritten->getRAngleLoc());
+
+  Sema::InstantiatingTemplate Inst(
+      *this, ArgsAsWritten->arguments().front().getSourceRange().getBegin(),
+      Sema::InstantiatingTemplate::ConstraintNormalization{},
+      CSE->getNamedConcept(),
+      ArgsAsWritten->arguments().front().getSourceRange());
----------------
zyn0217 wrote:

```cpp
if (Inst.isInvalid())
  return ExprError();
```

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