Don't try to typo-correct 'super' in an objc method.

This created 2 issues:

1) Performance issue, since typo-correction with PCH/modules is rather expensive.
2) Correctness issue, since if it managed to "correct" 'super' then bogus compiler errors would
be emitted, like this:

3.m:8:3: error: unknown type name 'super'; did you mean 'super1'?
  super.x = 0;
  ^~~~~
  super1
t3.m:5:13: note: 'super1' declared here
typedef int super1;
            ^
t3.m:8:8: error: expected identifier or '('
  super.x = 0;
       ^

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177126 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/DiagnosticSemaKinds.td

@@ -6074,6 +6074,8 @@ def warn_direct_ivar_access : Warning<"instance variable %0 is being "
   "directly accessed">, InGroup<DiagGroup<"direct-ivar-access">>, DefaultIgnore;
 
 // Spell-checking diagnostics
+def warn_spellcheck_initiated : Warning<"spell-checking initiated for %0">,
+  InGroup<DiagGroup<"spellcheck">>, DefaultIgnore;
 def err_unknown_type_or_class_name_suggest : Error<
   "unknown %select{type|class}2 name %0; did you mean %1?">;
 def err_unknown_typename_suggest : Error<

include/clang/Sema/Sema.h

@@ -7430,6 +7430,8 @@ private:
   /// The parser maintains this state here.
   Scope *CurScope;
 
+  mutable IdentifierInfo *Ident_super;
+
 protected:
   friend class Parser;
   friend class InitializationSequence;
@@ -7447,6 +7449,8 @@ public:
   /// template substitution or instantiation.
   Scope *getCurScope() const { return CurScope; }
 
+  IdentifierInfo *getSuperIdentifier() const;
+
   Decl *getObjCDeclContext() const;
 
   DeclContext *getCurLexicalContext() const {

lib/Sema/Sema.cpp

@@ -90,7 +90,7 @@ Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
     AccessCheckingSFINAE(false), InNonInstantiationSFINAEContext(false),
     NonInstantiationEntries(0), ArgumentPackSubstitutionIndex(-1),
     CurrentInstantiationScope(0), TyposCorrected(0),
-    AnalysisWarnings(*this)
+    AnalysisWarnings(*this), Ident_super(0)
 {
   TUScope = 0;
 
@@ -1302,3 +1302,9 @@ bool Sema::tryToRecoverWithCall(ExprResult &E, const PartialDiagnostic &PD,
   E = ExprError();
   return true;
 }
+
+IdentifierInfo *Sema::getSuperIdentifier() const {
+  if (!Ident_super)
+    Ident_super = &Context.Idents.get("super");
+  return Ident_super;
+}

lib/Sema/SemaCodeComplete.cpp

@@ -5315,7 +5315,7 @@ void Sema::CodeCompleteObjCSuperMessage(Scope *S, SourceLocation SuperLoc,
   } else {
     // "super" may be the name of a type or variable. Figure out which
     // it is.
-    IdentifierInfo *Super = &Context.Idents.get("super");
+    IdentifierInfo *Super = getSuperIdentifier();
     NamedDecl *ND = LookupSingleName(S, Super, SuperLoc, 
                                      LookupOrdinaryName);
     if ((CDecl = dyn_cast_or_null<ObjCInterfaceDecl>(ND))) {

lib/Sema/SemaLookup.cpp

@@ -3734,6 +3734,16 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
   if (!ActiveTemplateInstantiations.empty())
     return TypoCorrection();
 
+  // Don't try to correct 'super'.
+  if (S && S->isInObjcMethodScope() && Typo == getSuperIdentifier())
+    return TypoCorrection();
+
+  // This is for regression testing. It's disabled by default.
+  if (Diags.getDiagnosticLevel(diag::warn_spellcheck_initiated,
+                               TypoName.getLoc()) != DiagnosticsEngine::Ignored)
+    Diag(TypoName.getLoc(), diag::warn_spellcheck_initiated)
+      << TypoName.getName();
+
   NamespaceSpecifierSet Namespaces(Context, CurContext, SS);
 
   TypoCorrectionConsumer Consumer(*this, Typo);

test/SemaObjC/typo-correction.m

@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only -Wspellcheck
+
+@interface B
+@property int x;
+@end
+
+@interface S : B
+@end
+
+// Spell-checking 'undefined' is ok.
+undefined var; // expected-warning {{spell-checking initiated}} \
+               // expected-error {{unknown type name}}
+
+typedef int super1;
+@implementation S
+-(void)foo {
+  // Spell-checking 'super' is not ok.
+  super.x = 0;
+  self.x = 0;
+}
+@end