[clang] Changes to produce sugared converted template arguments

Makes CheckTemplateArgumentList and the template deduction functions
produce a sugared converted argument list in addition to the canonical one.

This is mostly NFC except that we hook this up to a few diagnostics in
SemaOverload.

The infrastructure here will be used in subsequent patches
where we perform a finalized sugared substitution for entities
which we do not unique per specializations on canonical arguments,
and later on will be used for template specialization resugaring.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D133874

clang/include/clang/Sema/Sema.h

@@ -8224,14 +8224,13 @@ class Sema final {
     CTAK_DeducedFromArrayBound
   };
 
-  bool CheckTemplateArgument(NamedDecl *Param,
-                             TemplateArgumentLoc &Arg,
-                             NamedDecl *Template,
-                             SourceLocation TemplateLoc,
-                             SourceLocation RAngleLoc,
-                             unsigned ArgumentPackIndex,
-                           SmallVectorImpl<TemplateArgument> &Converted,
-                             CheckTemplateArgumentKind CTAK = CTAK_Specified);
+  bool
+  CheckTemplateArgument(NamedDecl *Param, TemplateArgumentLoc &Arg,
+                        NamedDecl *Template, SourceLocation TemplateLoc,
+                        SourceLocation RAngleLoc, unsigned ArgumentPackIndex,
+                        SmallVectorImpl<TemplateArgument> &SugaredConverted,
+                        SmallVectorImpl<TemplateArgument> &CanonicalConverted,
+                        CheckTemplateArgumentKind CTAK);
 
   /// Check that the given template arguments can be be provided to
   /// the given template, converting the arguments along the way.
@@ -8262,23 +8261,25 @@ class Sema final {
   /// the template not being satisfied by the template arguments.
   ///
   /// \returns true if an error occurred, false otherwise.
-  bool CheckTemplateArgumentList(TemplateDecl *Template,
-                                 SourceLocation TemplateLoc,
-                                 TemplateArgumentListInfo &TemplateArgs,
-                                 bool PartialTemplateArgs,
-                                 SmallVectorImpl<TemplateArgument> &Converted,
-                                 bool UpdateArgsWithConversions = true,
-                                 bool *ConstraintsNotSatisfied = nullptr);
-
-  bool CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
-                                 TemplateArgumentLoc &Arg,
-                           SmallVectorImpl<TemplateArgument> &Converted);
+  bool CheckTemplateArgumentList(
+      TemplateDecl *Template, SourceLocation TemplateLoc,
+      TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
+      SmallVectorImpl<TemplateArgument> &SugaredConverted,
+      SmallVectorImpl<TemplateArgument> &CanonicalConverted,
+      bool UpdateArgsWithConversions = true,
+      bool *ConstraintsNotSatisfied = nullptr);
+
+  bool CheckTemplateTypeArgument(
+      TemplateTypeParmDecl *Param, TemplateArgumentLoc &Arg,
+      SmallVectorImpl<TemplateArgument> &SugaredConverted,
+      SmallVectorImpl<TemplateArgument> &CanonicalConverted);
 
   bool CheckTemplateArgument(TypeSourceInfo *Arg);
   ExprResult CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
                                    QualType InstantiatedParamType, Expr *Arg,
-                                   TemplateArgument &Converted,
-                               CheckTemplateArgumentKind CTAK = CTAK_Specified);
+                                   TemplateArgument &SugaredConverted,
+                                   TemplateArgument &CanonicalConverted,
+                                   CheckTemplateArgumentKind CTAK);
   bool CheckTemplateTemplateArgument(TemplateTemplateParmDecl *Param,
                                      TemplateParameterList *Params,
                                      TemplateArgumentLoc &Arg);

clang/include/clang/Sema/TemplateDeduction.h

@@ -41,7 +41,7 @@ namespace sema {
 /// TemplateDeductionResult value.
 class TemplateDeductionInfo {
   /// The deduced template argument list.
-  TemplateArgumentList *Deduced = nullptr;
+  TemplateArgumentList *DeducedSugared = nullptr, *DeducedCanonical = nullptr;
 
   /// The source location at which template argument
   /// deduction is occurring.
@@ -71,8 +71,8 @@ class TemplateDeductionInfo {
   /// Create temporary template deduction info for speculatively deducing
   /// against a base class of an argument's type.
   TemplateDeductionInfo(ForBaseTag, const TemplateDeductionInfo &Info)
-      : Deduced(Info.Deduced), Loc(Info.Loc), DeducedDepth(Info.DeducedDepth),
-        ExplicitArgs(Info.ExplicitArgs) {}
+      : DeducedSugared(Info.DeducedSugared), Loc(Info.Loc),
+        DeducedDepth(Info.DeducedDepth), ExplicitArgs(Info.ExplicitArgs) {}
 
   /// Returns the location at which template argument is
   /// occurring.
@@ -91,10 +91,15 @@ class TemplateDeductionInfo {
     return ExplicitArgs;
   }
 
-  /// Take ownership of the deduced template argument list.
-  TemplateArgumentList *take() {
-    TemplateArgumentList *Result = Deduced;
-    Deduced = nullptr;
+  /// Take ownership of the deduced template argument lists.
+  TemplateArgumentList *takeSugared() {
+    TemplateArgumentList *Result = DeducedSugared;
+    DeducedSugared = nullptr;
+    return Result;
+  }
+  TemplateArgumentList *takeCanonical() {
+    TemplateArgumentList *Result = DeducedCanonical;
+    DeducedCanonical = nullptr;
     return Result;
   }
 
@@ -120,15 +125,20 @@ class TemplateDeductionInfo {
 
   /// Provide an initial template argument list that contains the
   /// explicitly-specified arguments.
-  void setExplicitArgs(TemplateArgumentList *NewDeduced) {
-    Deduced = NewDeduced;
-    ExplicitArgs = Deduced->size();
+  void setExplicitArgs(TemplateArgumentList *NewDeducedSugared,
+                       TemplateArgumentList *NewDeducedCanonical) {
+    assert(NewDeducedSugared->size() == NewDeducedCanonical->size());
+    DeducedSugared = NewDeducedSugared;
+    DeducedCanonical = NewDeducedCanonical;
+    ExplicitArgs = DeducedSugared->size();
   }
 
   /// Provide a new template argument list that contains the
   /// results of template argument deduction.
-  void reset(TemplateArgumentList *NewDeduced) {
-    Deduced = NewDeduced;
+  void reset(TemplateArgumentList *NewDeducedSugared,
+             TemplateArgumentList *NewDeducedCanonical) {
+    DeducedSugared = NewDeducedSugared;
+    DeducedCanonical = NewDeducedCanonical;
   }
 
   /// Is a SFINAE diagnostic available?

clang/lib/Sema/SemaLookup.cpp

@@ -3694,11 +3694,11 @@ Sema::LookupLiteralOperator(Scope *S, LookupResult &R,
         // is a well-formed template argument for the template parameter.
         if (StringLit) {
           SFINAETrap Trap(*this);
-          SmallVector<TemplateArgument, 1> Checked;
+          SmallVector<TemplateArgument, 1> SugaredChecked, CanonicalChecked;
           TemplateArgumentLoc Arg(TemplateArgument(StringLit), StringLit);
-          if (CheckTemplateArgument(Params->getParam(0), Arg, FD,
-                                    R.getNameLoc(), R.getNameLoc(), 0,
-                                    Checked) ||
+          if (CheckTemplateArgument(
+                  Params->getParam(0), Arg, FD, R.getNameLoc(), R.getNameLoc(),
+                  0, SugaredChecked, CanonicalChecked, CTAK_Specified) ||
               Trap.hasErrorOccurred())
             IsTemplate = false;
         }

clang/lib/Sema/SemaOverload.cpp

@@ -640,7 +640,7 @@ clang::MakeDeductionFailureInfo(ASTContext &Context,
     auto *Saved = new (Context) DFIDeducedMismatchArgs;
     Saved->FirstArg = Info.FirstArg;
     Saved->SecondArg = Info.SecondArg;
-    Saved->TemplateArgs = Info.take();
+    Saved->TemplateArgs = Info.takeSugared();
     Saved->CallArgIndex = Info.CallArgIndex;
     Result.Data = Saved;
     break;
@@ -669,7 +669,7 @@ clang::MakeDeductionFailureInfo(ASTContext &Context,
   }
 
   case Sema::TDK_SubstitutionFailure:
-    Result.Data = Info.take();
+    Result.Data = Info.takeSugared();
     if (Info.hasSFINAEDiagnostic()) {
       PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt(
           SourceLocation(), PartialDiagnostic::NullDiagnostic());
@@ -680,7 +680,7 @@ clang::MakeDeductionFailureInfo(ASTContext &Context,
 
   case Sema::TDK_ConstraintsNotSatisfied: {
     CNSInfo *Saved = new (Context) CNSInfo;
-    Saved->TemplateArgs = Info.take();
+    Saved->TemplateArgs = Info.takeSugared();
     Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction;
     Result.Data = Saved;
     break;