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

[Erich Keane via libcxx-commits]

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@@ -16,130 +16,385 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclTemplate.h"
 #include "clang/AST/Expr.h"
+#include "clang/AST/ExprConcepts.h"
 #include "clang/Basic/SourceLocation.h"
+#include "clang/Sema/Ownership.h"
 #include "llvm/ADT/FoldingSet.h"
-#include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/STLFunctionalExtras.h"
+#include "llvm/ADT/SmallBitVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include <optional>
 #include <utility>
 
 namespace clang {
 class Sema;
+class MultiLevelTemplateArgumentList;
 
-enum { ConstraintAlignment = 8 };
+/// \brief A normalized constraint, as defined in C++ [temp.constr.normal], is
+/// either an atomic constraint, a conjunction of normalized constraints or a
+/// disjunction of normalized constraints.
+struct NormalizedConstraint {
+
+  enum class ConstraintKind : unsigned char {
+    Atomic = 0,
+    ConceptId,
+    FoldExpanded,
+    Compound,
+  };
+
+  enum CompoundConstraintKind : unsigned char {
+    CCK_Conjunction,
+    CCK_Disjunction
+  };
+  enum class FoldOperatorKind : unsigned char { And, Or };
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erichkeane wrote:

It seems perhaps there is 1 too many enums here.  Either Compound Constraints are just a constraint kind, or Fold & Compound are the same thing? 

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