[llvm-branch-commits] [clang] [clang] Finish implementation of P0522 (PR #96023)

[via llvm-branch-commits]

================
@@ -6369,27 +6451,88 @@ bool Sema::isTemplateTemplateParameterAtLeastAsSpecializedAs(
   //   be inverted between Ps and As. On non-deduced context, matching needs to
   //   happen both ways, according to [temp.arg.template]p3, but this is
   //   currently implemented as a special case elsewhere.
-  if (::DeduceTemplateArguments(*this, A, AArgs, PArgs, Info, Deduced,
-                                /*NumberOfArgumentsMustMatch=*/false,
-                                IsDeduced ? PackFold::ArgumentToParameter
-                                          : PackFold::ParameterToArgument) !=
-      TemplateDeductionResult::Success)
+  switch (TemplateDeductionResult Result = ::DeduceTemplateArguments(
+              *this, A, AArgs, PArgs, Info, Deduced,
+              /*NumberOfArgumentsMustMatch=*/false,
+              IsDeduced ? PackFold::ArgumentToParameter : PackFold::Both)) {
+  case clang::TemplateDeductionResult::Success:
+    break;
+
+  case TemplateDeductionResult::MiscellaneousDeductionFailure:
+    Diag(AArg->getLocation(), diag::err_template_param_list_different_arity)
+        << (A->size() > P->size()) << /*isTemplateTemplateParameter=*/true
+        << SourceRange(A->getTemplateLoc(), P->getRAngleLoc());
+    return false;
+  case TemplateDeductionResult::NonDeducedMismatch:
+    Diag(AArg->getLocation(), diag::err_non_deduced_mismatch)
+        << Info.FirstArg << Info.SecondArg;
+    return false;
+  case TemplateDeductionResult::Inconsistent:
+    Diag(getAsNamedDecl(Info.Param)->getLocation(),
+         diag::err_inconsistent_deduction)
+        << Info.FirstArg << Info.SecondArg;
+    return false;
+  case TemplateDeductionResult::AlreadyDiagnosed:
     return false;
 
+  // None of these should happen for a plain deduction.
+  case TemplateDeductionResult::Invalid:
+  case TemplateDeductionResult::InstantiationDepth:
+  case TemplateDeductionResult::Incomplete:
+  case TemplateDeductionResult::IncompletePack:
+  case TemplateDeductionResult::Underqualified:
+  case TemplateDeductionResult::SubstitutionFailure:
+  case TemplateDeductionResult::DeducedMismatch:
+  case TemplateDeductionResult::DeducedMismatchNested:
+  case TemplateDeductionResult::TooManyArguments:
+  case TemplateDeductionResult::TooFewArguments:
+  case TemplateDeductionResult::InvalidExplicitArguments:
+  case TemplateDeductionResult::NonDependentConversionFailure:
+  case TemplateDeductionResult::ConstraintsNotSatisfied:
+  case TemplateDeductionResult::CUDATargetMismatch:
+    llvm_unreachable("Unexpected Result");
+  }
+
   SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
-  Sema::InstantiatingTemplate Inst(*this, Info.getLocation(), AArg, DeducedArgs,
-                                   Info);
-  if (Inst.isInvalid())
-    return false;
 
-  bool AtLeastAsSpecialized;
+  TemplateDeductionResult TDK;
   runWithSufficientStackSpace(Info.getLocation(), [&] {
-    AtLeastAsSpecialized =
-        ::FinishTemplateArgumentDeduction(
-            *this, AArg, /*IsPartialOrdering=*/true, PArgs, Deduced, Info) ==
-        TemplateDeductionResult::Success;
+    TDK = ::FinishTemplateArgumentDeduction(
+        *this, AArg, /*IsPartialOrdering=*/true, PArgs, Deduced, Info);
   });
-  return AtLeastAsSpecialized;
+  switch (TDK) {
+  case TemplateDeductionResult::Success:
+    return true;
+
+  // It doesn't seem possible to get a non-deduced mismatch when partial
+  // ordering TTPs.
+  case TemplateDeductionResult::NonDeducedMismatch:
+    llvm_unreachable("Unexpected NonDeducedMismatch");
+
+  // Substitution failures should have already been diagnosed.
+  case TemplateDeductionResult::AlreadyDiagnosed:
+  case TemplateDeductionResult::SubstitutionFailure:
+  case TemplateDeductionResult::InstantiationDepth:
+    return false;
+
+  // None of these should happen when just converting deduced arguments.
+  case TemplateDeductionResult::Invalid:
+  case TemplateDeductionResult::Incomplete:
+  case TemplateDeductionResult::IncompletePack:
+  case TemplateDeductionResult::Inconsistent:
+  case TemplateDeductionResult::Underqualified:
+  case TemplateDeductionResult::DeducedMismatch:
+  case TemplateDeductionResult::DeducedMismatchNested:
+  case TemplateDeductionResult::TooManyArguments:
+  case TemplateDeductionResult::TooFewArguments:
+  case TemplateDeductionResult::InvalidExplicitArguments:
+  case TemplateDeductionResult::NonDependentConversionFailure:
+  case TemplateDeductionResult::ConstraintsNotSatisfied:
+  case TemplateDeductionResult::MiscellaneousDeductionFailure:
+  case TemplateDeductionResult::CUDATargetMismatch:
+    llvm_unreachable("Unexpected Result");
----------------
cor3ntin wrote:

Ditto

https://github.com/llvm/llvm-project/pull/96023