[libcxx-commits] [clang] [libcxx] [Clang] Normalize constraints before checking for satisfaction (PR #141776)

[Erich Keane via libcxx-commits]

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@@ -28,10 +28,19 @@ namespace clang {
 
 class ConceptDecl;
 class TemplateDecl;
+class ConceptReference;
 class Expr;
 class NamedDecl;
 struct PrintingPolicy;
 
+/// Pairs of unsatisfied atomic constraint expressions along with the
+/// substituted constraint expr, if the template arguments could be
+/// substituted into them, or a diagnostic if substitution resulted in
+/// an invalid expression.
+using UnsatisfiedConstraintRecord =
+    llvm::PointerUnion<const Expr *, const ConceptReference *,
+                       std::pair<SourceLocation, StringRef> *>;
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erichkeane wrote:

This probably just needs to be a struct type.  The union + pair + 2 different things results in some pretty unreadable code below.

https://github.com/llvm/llvm-project/pull/141776