Convert SemaDecl.cpp to pass callback objects to CorrectTypo.

Includes tests highlighting the cases where accuracy has improved
(there is one call that does no filtering beyond selecting the set
of allowed keywords, and one call that only triggers for ObjC code
for which a test by someone who knows ObjC would be welcome). Also
fixes a small typo in one of the suggestion messages, and drops a
malformed "expected-note" for a suggestion that did not occur even
when the malformed note was committed as r145930.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148420 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 82 insertions, 47 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 61e104fd1d..f2af0a7075 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -55,6 +55,30 @@ Sema::DeclGroupPtrTy Sema::ConvertDeclToDeclGroup(Decl *Ptr, Decl *OwnedType) {
   return DeclGroupPtrTy::make(DeclGroupRef(Ptr));
 }
 
+namespace {
+
+class TypeNameValidatorCCC : public CorrectionCandidateCallback {
+ public:
+  TypeNameValidatorCCC(bool AllowInvalid) : AllowInvalidDecl(AllowInvalid) {
+    WantExpressionKeywords = false;
+    WantCXXNamedCasts = false;
+    WantRemainingKeywords = false;
+  }
+
+  virtual bool ValidateCandidate(const TypoCorrection &candidate) {
+    if (NamedDecl *ND = candidate.getCorrectionDecl())
+      return (isa<TypeDecl>(ND) || isa<ObjCInterfaceDecl>(ND)) &&
+          (AllowInvalidDecl || !ND->isInvalidDecl());
+    else
+      return candidate.isKeyword();
+  }
+
+ private:
+  bool AllowInvalidDecl;
+};
+
+}
+
 /// \brief If the identifier refers to a type name within this scope,
 /// return the declaration of that type.
 ///
@@ -147,9 +171,9 @@ ParsedType Sema::getTypeName(IdentifierInfo &II, SourceLocation NameLoc,
   case LookupResult::NotFound:
   case LookupResult::NotFoundInCurrentInstantiation:
     if (CorrectedII) {
+      TypeNameValidatorCCC Validator(true);
       TypoCorrection Correction = CorrectTypo(Result.getLookupNameInfo(),
-                                              Kind, S, SS, 0, false,
-                                              Sema::CTC_Type);
+                                              Kind, S, SS, &Validator);
       IdentifierInfo *NewII = Correction.getCorrectionAsIdentifierInfo();
       TemplateTy Template;
       bool MemberOfUnknownSpecialization;
@@ -339,9 +363,10 @@ bool Sema::DiagnoseUnknownTypeName(const IdentifierInfo &II,
   
   // There may have been a typo in the name of the type. Look up typo
   // results, in case we have something that we can suggest.
+  TypeNameValidatorCCC Validator(false);
   if (TypoCorrection Corrected = CorrectTypo(DeclarationNameInfo(&II, IILoc),
-                                             LookupOrdinaryName, S, SS, NULL,
-                                             false, CTC_Type)) {
+                                             LookupOrdinaryName, S, SS,
+                                             &Validator)) {
     std::string CorrectedStr(Corrected.getAsString(getLangOptions()));
     std::string CorrectedQuotedStr(Corrected.getQuoted(getLangOptions()));
 
@@ -350,32 +375,28 @@ bool Sema::DiagnoseUnknownTypeName(const IdentifierInfo &II,
       // FIXME: Actually recover with the keyword we suggest, and emit a fix-it.
       Diag(IILoc, diag::err_unknown_typename_suggest)
         << &II << CorrectedQuotedStr;
-      return true;      
     } else {
       NamedDecl *Result = Corrected.getCorrectionDecl();
-      if ((isa<TypeDecl>(Result) || isa<ObjCInterfaceDecl>(Result)) &&
-          !Result->isInvalidDecl()) {
-        // We found a similarly-named type or interface; suggest that.
-        if (!SS || !SS->isSet())
-          Diag(IILoc, diag::err_unknown_typename_suggest)
-            << &II << CorrectedQuotedStr
-            << FixItHint::CreateReplacement(SourceRange(IILoc), CorrectedStr);
-        else if (DeclContext *DC = computeDeclContext(*SS, false))
-          Diag(IILoc, diag::err_unknown_nested_typename_suggest) 
-            << &II << DC << CorrectedQuotedStr << SS->getRange()
-            << FixItHint::CreateReplacement(SourceRange(IILoc), CorrectedStr);
-        else
-          llvm_unreachable("could not have corrected a typo here");
+      // We found a similarly-named type or interface; suggest that.
+      if (!SS || !SS->isSet())
+        Diag(IILoc, diag::err_unknown_typename_suggest)
+          << &II << CorrectedQuotedStr
+          << FixItHint::CreateReplacement(SourceRange(IILoc), CorrectedStr);
+      else if (DeclContext *DC = computeDeclContext(*SS, false))
+        Diag(IILoc, diag::err_unknown_nested_typename_suggest)
+          << &II << DC << CorrectedQuotedStr << SS->getRange()
+          << FixItHint::CreateReplacement(SourceRange(IILoc), CorrectedStr);
+      else
+        llvm_unreachable("could not have corrected a typo here");
 
-        Diag(Result->getLocation(), diag::note_previous_decl)
-          << CorrectedQuotedStr;
-        
-        SuggestedType = getTypeName(*Result->getIdentifier(), IILoc, S, SS,
-                                    false, false, ParsedType(),
-                                    /*NonTrivialTypeSourceInfo=*/true);
-        return true;
-      }
+      Diag(Result->getLocation(), diag::note_previous_decl)
+        << CorrectedQuotedStr;
+
+      SuggestedType = getTypeName(*Result->getIdentifier(), IILoc, S, SS,
+                                  false, false, ParsedType(),
+                                  /*NonTrivialTypeSourceInfo=*/true);
     }
+    return true;
   }
 
   if (getLangOptions().CPlusPlus) {
@@ -546,9 +567,10 @@ Corrected:
     // close to this name.
     if (!SecondTry) {
       SecondTry = true;
+      CorrectionCandidateCallback DefaultValidator;
       if (TypoCorrection Corrected = CorrectTypo(Result.getLookupNameInfo(),
                                                  Result.getLookupKind(), S, 
-                                                 &SS)) {
+                                                 &SS, &DefaultValidator)) {
         unsigned UnqualifiedDiag = diag::err_undeclared_var_use_suggest;
         unsigned QualifiedDiag = diag::err_no_member_suggest;
         std::string CorrectedStr(Corrected.getAsString(getLangOptions()));
@@ -1241,10 +1263,11 @@ ObjCInterfaceDecl *Sema::getObjCInterfaceDecl(IdentifierInfo *&Id,
   if (!IDecl && DoTypoCorrection) {
     // Perform typo correction at the given location, but only if we
     // find an Objective-C class name.
-    TypoCorrection C;
-    if ((C = CorrectTypo(DeclarationNameInfo(Id, IdLoc), LookupOrdinaryName,
-                         TUScope, NULL, NULL, false, CTC_NoKeywords)) &&
-        (IDecl = C.getCorrectionDeclAs<ObjCInterfaceDecl>())) {
+    DeclFilterCCC<ObjCInterfaceDecl> Validator;
+    if (TypoCorrection C = CorrectTypo(DeclarationNameInfo(Id, IdLoc),
+                                       LookupOrdinaryName, TUScope, NULL,
+                                       &Validator)) {
+      IDecl = C.getCorrectionDeclAs<ObjCInterfaceDecl>();
       Diag(IdLoc, diag::err_undef_interface_suggest)
         << Id << IDecl->getDeclName() 
         << FixItHint::CreateReplacement(IdLoc, IDecl->getNameAsString());
@@ -4409,6 +4432,18 @@ namespace {
   };
 }
 
+namespace {
+
+// Callback to only accept typo corrections that have a non-zero edit distance.
+class DifferentNameValidatorCCC : public CorrectionCandidateCallback {
+ public:
+  virtual bool ValidateCandidate(const TypoCorrection &candidate) {
+    return candidate.getEditDistance() > 0;
+  }
+};
+
+}
+
 /// \brief Generate diagnostics for an invalid function redeclaration.
 ///
 /// This routine handles generating the diagnostic messages for an invalid
@@ -4438,6 +4473,7 @@ static NamedDecl* DiagnoseInvalidRedeclaration(
   SemaRef.LookupQualifiedName(Prev, NewDC);
   assert(!Prev.isAmbiguous() &&
          "Cannot have an ambiguity in previous-declaration lookup");
+  DifferentNameValidatorCCC Validator;
   if (!Prev.empty()) {
     for (LookupResult::iterator Func = Prev.begin(), FuncEnd = Prev.end();
          Func != FuncEnd; ++Func) {
@@ -4453,8 +4489,8 @@ static NamedDecl* DiagnoseInvalidRedeclaration(
     }
   // If the qualified name lookup yielded nothing, try typo correction
   } else if ((Correction = SemaRef.CorrectTypo(Prev.getLookupNameInfo(),
-                                         Prev.getLookupKind(), 0, 0, NewDC)) &&
-             Correction.getCorrection() != Name) {
+                                         Prev.getLookupKind(), 0, 0,
+                                         &Validator, NewDC))) {
     // Trap errors.
     Sema::SFINAETrap Trap(SemaRef);
 
@@ -7309,21 +7345,20 @@ NamedDecl *Sema::ImplicitlyDefineFunction(SourceLocation Loc,
   // function declaration is going to be treated as an error.
   if (Diags.getDiagnosticLevel(diag_id, Loc) >= DiagnosticsEngine::Error) {
     TypoCorrection Corrected;
+    DeclFilterCCC<FunctionDecl> Validator;
     if (S && (Corrected = CorrectTypo(DeclarationNameInfo(&II, Loc),
-                                      LookupOrdinaryName, S, 0))) {
-      NamedDecl *Decl = Corrected.getCorrectionDecl();
-      if (FunctionDecl *Func = dyn_cast_or_null<FunctionDecl>(Decl)) {
-        std::string CorrectedStr = Corrected.getAsString(getLangOptions());
-        std::string CorrectedQuotedStr = Corrected.getQuoted(getLangOptions());
-
-        Diag(Loc, diag::note_function_suggestion) << CorrectedQuotedStr
-            << FixItHint::CreateReplacement(Loc, CorrectedStr);
-
-        if (Func->getLocation().isValid()
-            && !II.getName().startswith("__builtin_"))
-          Diag(Func->getLocation(), diag::note_previous_decl)
-              << CorrectedQuotedStr;
-      }
+                                      LookupOrdinaryName, S, 0, &Validator))) {
+      std::string CorrectedStr = Corrected.getAsString(getLangOptions());
+      std::string CorrectedQuotedStr = Corrected.getQuoted(getLangOptions());
+      FunctionDecl *Func = Corrected.getCorrectionDeclAs<FunctionDecl>();
+
+      Diag(Loc, diag::note_function_suggestion) << CorrectedQuotedStr
+          << FixItHint::CreateReplacement(Loc, CorrectedStr);
+
+      if (Func->getLocation().isValid()
+          && !II.getName().startswith("__builtin_"))
+        Diag(Func->getLocation(), diag::note_previous_decl)
+            << CorrectedQuotedStr;
     }
   }