Teach typo correction about various language keywords. We can't

generally recover from typos in keywords (since we would effectively
have to mangle the token stream). However, there are still benefits to
typo-correcting with keywords:
  - We don't make stupid suggestions when the user typed something
  that is similar to a keyword. 
  - We can suggest the keyword in a diagnostic (did you mean
  "static_cast"?), even if we can't recover and therefore don't have
  a fix-it.

llvm-svn: 101274

1 files changed, 46 insertions, 33 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index d10ea6d4ab9..2a9af994933 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -946,43 +946,55 @@ bool Sema::DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS,
   }
 
   // We didn't find anything, so try to correct for a typo.
-  if (S && CorrectTypo(R, S, &SS)) {
-    if (isa<ValueDecl>(*R.begin()) || isa<FunctionTemplateDecl>(*R.begin())) {
-      if (SS.isEmpty())
-        Diag(R.getNameLoc(), diagnostic_suggest) << Name << R.getLookupName()
-          << FixItHint::CreateReplacement(R.getNameLoc(),
-                                          R.getLookupName().getAsString());
-      else
-        Diag(R.getNameLoc(), diag::err_no_member_suggest)
-          << Name << computeDeclContext(SS, false) << R.getLookupName()
-          << SS.getRange()
-          << FixItHint::CreateReplacement(R.getNameLoc(),
-                                          R.getLookupName().getAsString());
-      if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
-        Diag(ND->getLocation(), diag::note_previous_decl)
-          << ND->getDeclName();
-
-      // Tell the callee to try to recover.
-      return false;
-    }
+  DeclarationName Corrected;
+  if (S && (Corrected = CorrectTypo(R, S, &SS))) {
+    if (!R.empty()) {
+      if (isa<ValueDecl>(*R.begin()) || isa<FunctionTemplateDecl>(*R.begin())) {
+        if (SS.isEmpty())
+          Diag(R.getNameLoc(), diagnostic_suggest) << Name << R.getLookupName()
+            << FixItHint::CreateReplacement(R.getNameLoc(),
+                                            R.getLookupName().getAsString());
+        else
+          Diag(R.getNameLoc(), diag::err_no_member_suggest)
+            << Name << computeDeclContext(SS, false) << R.getLookupName()
+            << SS.getRange()
+            << FixItHint::CreateReplacement(R.getNameLoc(),
+                                            R.getLookupName().getAsString());
+        if (NamedDecl *ND = R.getAsSingle<NamedDecl>())
+          Diag(ND->getLocation(), diag::note_previous_decl)
+            << ND->getDeclName();
+
+        // Tell the callee to try to recover.
+        return false;
+      }
+    
+      if (isa<TypeDecl>(*R.begin()) || isa<ObjCInterfaceDecl>(*R.begin())) {
+        // FIXME: If we ended up with a typo for a type name or
+        // Objective-C class name, we're in trouble because the parser
+        // is in the wrong place to recover. Suggest the typo
+        // correction, but don't make it a fix-it since we're not going
+        // to recover well anyway.
+        if (SS.isEmpty())
+          Diag(R.getNameLoc(), diagnostic_suggest) << Name << R.getLookupName();
+        else
+          Diag(R.getNameLoc(), diag::err_no_member_suggest)
+            << Name << computeDeclContext(SS, false) << R.getLookupName()
+            << SS.getRange();
 
-    if (isa<TypeDecl>(*R.begin()) || isa<ObjCInterfaceDecl>(*R.begin())) {
-      // FIXME: If we ended up with a typo for a type name or
-      // Objective-C class name, we're in trouble because the parser
-      // is in the wrong place to recover. Suggest the typo
-      // correction, but don't make it a fix-it since we're not going
-      // to recover well anyway.
+        // Don't try to recover; it won't work.
+        return true;
+      }
+    } else {
+      // FIXME: We found a keyword. Suggest it, but don't provide a fix-it 
+      // because we aren't able to recover.
       if (SS.isEmpty())
-        Diag(R.getNameLoc(), diagnostic_suggest) << Name << R.getLookupName();
+        Diag(R.getNameLoc(), diagnostic_suggest) << Name << Corrected;
       else
         Diag(R.getNameLoc(), diag::err_no_member_suggest)
-          << Name << computeDeclContext(SS, false) << R.getLookupName()
-          << SS.getRange();
-
-      // Don't try to recover; it won't work.
+        << Name << computeDeclContext(SS, false) << Corrected
+        << SS.getRange();
       return true;
     }
-
     R.clear();
   }
 
@@ -2575,7 +2587,8 @@ LookupMemberExprInRecord(Sema &SemaRef, LookupResult &R,
   // We didn't find anything with the given name, so try to correct
   // for typos.
   DeclarationName Name = R.getLookupName();
-  if (SemaRef.CorrectTypo(R, 0, &SS, DC) &&
+  if (SemaRef.CorrectTypo(R, 0, &SS, DC, false, Sema::CTC_MemberLookup) && 
+      !R.empty() &&
       (isa<ValueDecl>(*R.begin()) || isa<FunctionTemplateDecl>(*R.begin()))) {
     SemaRef.Diag(R.getNameLoc(), diag::err_no_member_suggest)
       << Name << DC << R.getLookupName() << SS.getRange()
@@ -3032,7 +3045,7 @@ Sema::LookupMemberExpr(LookupResult &R, Expr *&BaseExpr,
         // Attempt to correct for typos in ivar names.
         LookupResult Res(*this, R.getLookupName(), R.getNameLoc(),
                          LookupMemberName);
-        if (CorrectTypo(Res, 0, 0, IDecl) &&
+        if (CorrectTypo(Res, 0, 0, IDecl, false, CTC_MemberLookup) &&
             (IV = Res.getAsSingle<ObjCIvarDecl>())) {
           Diag(R.getNameLoc(),
                diag::err_typecheck_member_reference_ivar_suggest)