[ASTImporter] Remove redundant IsStructuralMatch overloads

[teemperor]

Summary

Nearly all of the overloads have pretty much the same behaviour. The only exception here
is that some of them call back GetOriginalDecl and others don't, but the only real user
of that overload (which is LLDB) actually prefers getting this callback.

[teemperor]

clang/lib/AST/ASTImporter.cpp

2179

(Importer.getToContext is actually not the ASTContext of To, so this technically can lead to creating types in the wrong ASTContext. I'll fix that in a follow-up either by changing this or removing the GetOriginalDecl above).

2185

Will turn that into a generic IsStructurallyEquivalent overload as a separate follow-up

[martong]

Makes sense! Thanks!

clang/lib/AST/ASTImporter.cpp

2179

uhh, okay.

[teemperor]

In D112796#3096016, @martong wrote:

Makes sense! Thanks!

Thanks for the quick review!

clang/lib/AST/ASTImporter.cpp

Error ImportDefaultArgOfParmVarDecl(const ParmVarDecl *FromParam,
                                         ParmVarDecl *ToParam);
 
     Expected<InheritedConstructor>
     ImportInheritedConstructor(const InheritedConstructor &From);
 
     template <typename T>
     bool hasSameVisibilityContextAndLinkage(T *Found, T *From);
 
-    bool IsStructuralMatch(Decl *From, Decl *To, bool Complain);
-    bool IsStructuralMatch(RecordDecl *FromRecord, RecordDecl *ToRecord,
-                           bool Complain = true);
-    bool IsStructuralMatch(VarDecl *FromVar, VarDecl *ToVar,
-                           bool Complain = true);
-    bool IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToRecord);
+    bool IsStructuralMatch(Decl *From, Decl *To, bool Complain = true);
     bool IsStructuralMatch(EnumConstantDecl *FromEC, EnumConstantDecl *ToEC);
-    bool IsStructuralMatch(FunctionTemplateDecl *From,
-                           FunctionTemplateDecl *To);
-    bool IsStructuralMatch(FunctionDecl *From, FunctionDecl *To);
-    bool IsStructuralMatch(ClassTemplateDecl *From, ClassTemplateDecl *To);
-    bool IsStructuralMatch(VarTemplateDecl *From, VarTemplateDecl *To);
     ExpectedDecl VisitDecl(Decl *D);
     ExpectedDecl VisitImportDecl(ImportDecl *D);
     ExpectedDecl VisitEmptyDecl(EmptyDecl *D);
     ExpectedDecl VisitAccessSpecDecl(AccessSpecDecl *D);
     ExpectedDecl VisitStaticAssertDecl(StaticAssertDecl *D);
     ExpectedDecl VisitTranslationUnitDecl(TranslationUnitDecl *D);
     ExpectedDecl VisitBindingDecl(BindingDecl *D);
     ExpectedDecl VisitNamespaceDecl(NamespaceDecl *D);

 
 static StructuralEquivalenceKind
 getStructuralEquivalenceKind(const ASTImporter &Importer) {
   return Importer.isMinimalImport() ? StructuralEquivalenceKind::Minimal
                                     : StructuralEquivalenceKind::Default;
 }
 
 bool ASTNodeImporter::IsStructuralMatch(Decl *From, Decl *To, bool Complain) {
-  StructuralEquivalenceContext Ctx(
-      Importer.getFromContext(), Importer.getToContext(),
-      Importer.getNonEquivalentDecls(), getStructuralEquivalenceKind(Importer),
-      false, Complain);
-  return Ctx.IsEquivalent(From, To);
-}
-
-bool ASTNodeImporter::IsStructuralMatch(RecordDecl *FromRecord,
-                                        RecordDecl *ToRecord, bool Complain) {
   // Eliminate a potential failure point where we attempt to re-import
   // something we're trying to import while completing ToRecord.
-  Decl *ToOrigin = Importer.GetOriginalDecl(ToRecord);
+  Decl *ToOrigin = Importer.GetOriginalDecl(To);
   if (ToOrigin) {
-    auto *ToOriginRecord = dyn_cast<RecordDecl>(ToOrigin);
-    if (ToOriginRecord)
-      ToRecord = ToOriginRecord;
-  }
-
-  StructuralEquivalenceContext Ctx(Importer.getFromContext(),
-                                   ToRecord->getASTContext(),
-                                   Importer.getNonEquivalentDecls(),
-                                   getStructuralEquivalenceKind(Importer),
-                                   false, Complain);
-  return Ctx.IsEquivalent(FromRecord, ToRecord);
+    To = ToOrigin;
   }
 
-bool ASTNodeImporter::IsStructuralMatch(VarDecl *FromVar, VarDecl *ToVar,
-                                        bool Complain) {
   StructuralEquivalenceContext Ctx(
       Importer.getFromContext(), Importer.getToContext(),
       Importer.getNonEquivalentDecls(), getStructuralEquivalenceKind(Importer),
       false, Complain);
-  return Ctx.IsEquivalent(FromVar, ToVar);
-}
-
-bool ASTNodeImporter::IsStructuralMatch(EnumDecl *FromEnum, EnumDecl *ToEnum) {
-  // Eliminate a potential failure point where we attempt to re-import
-  // something we're trying to import while completing ToEnum.
-  if (Decl *ToOrigin = Importer.GetOriginalDecl(ToEnum))
-    if (auto *ToOriginEnum = dyn_cast<EnumDecl>(ToOrigin))
-        ToEnum = ToOriginEnum;
-
-  StructuralEquivalenceContext Ctx(
-      Importer.getFromContext(), Importer.getToContext(),
-      Importer.getNonEquivalentDecls(), getStructuralEquivalenceKind(Importer));
-  return Ctx.IsEquivalent(FromEnum, ToEnum);
-}
-
-bool ASTNodeImporter::IsStructuralMatch(FunctionTemplateDecl *From,
-                                        FunctionTemplateDecl *To) {
-  StructuralEquivalenceContext Ctx(
-      Importer.getFromContext(), Importer.getToContext(),
-      Importer.getNonEquivalentDecls(), getStructuralEquivalenceKind(Importer),
-      false, false);
-  return Ctx.IsEquivalent(From, To);
-}
-
-bool ASTNodeImporter::IsStructuralMatch(FunctionDecl *From, FunctionDecl *To) {
-  StructuralEquivalenceContext Ctx(
-      Importer.getFromContext(), Importer.getToContext(),
-      Importer.getNonEquivalentDecls(), getStructuralEquivalenceKind(Importer),
-      false, false);
   return Ctx.IsEquivalent(From, To);
 }
 
 bool ASTNodeImporter::IsStructuralMatch(EnumConstantDecl *FromEC,
                                         EnumConstantDecl *ToEC) {
   const llvm::APSInt &FromVal = FromEC->getInitVal();
   const llvm::APSInt &ToVal = ToEC->getInitVal();
 
   return FromVal.isSigned() == ToVal.isSigned() &&
          FromVal.getBitWidth() == ToVal.getBitWidth() &&
          FromVal == ToVal;
 }
 
-bool ASTNodeImporter::IsStructuralMatch(ClassTemplateDecl *From,
-                                        ClassTemplateDecl *To) {
-  StructuralEquivalenceContext Ctx(Importer.getFromContext(),
-                                   Importer.getToContext(),
-                                   Importer.getNonEquivalentDecls(),
-                                   getStructuralEquivalenceKind(Importer));
-  return Ctx.IsEquivalent(From, To);
-}
-
-bool ASTNodeImporter::IsStructuralMatch(VarTemplateDecl *From,
-                                        VarTemplateDecl *To) {
-  StructuralEquivalenceContext Ctx(Importer.getFromContext(),
-                                   Importer.getToContext(),
-                                   Importer.getNonEquivalentDecls(),
-                                   getStructuralEquivalenceKind(Importer));
-  return Ctx.IsEquivalent(From, To);
-}
-
 ExpectedDecl ASTNodeImporter::VisitDecl(Decl *D) {
   Importer.FromDiag(D->getLocation(), diag::err_unsupported_ast_node)
     << D->getDeclKindName();
   return make_error<ImportError>(ImportError::UnsupportedConstruct);
 }
 
 ExpectedDecl ASTNodeImporter::VisitImportDecl(ImportDecl *D) {
   Importer.FromDiag(D->getLocation(), diag::err_unsupported_ast_node)