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.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101274 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 30 insertions, 26 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index a2d0e18728..8e46b9b657 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -246,32 +246,36 @@ bool Sema::DiagnoseUnknownTypeName(const IdentifierInfo &II,
   LookupResult Lookup(*this, &II, IILoc, LookupOrdinaryName, 
                       NotForRedeclaration);
 
-  // FIXME: It would be nice if we could correct for typos in built-in
-  // names, such as "itn" for "int".
-
-  if (CorrectTypo(Lookup, S, SS) && Lookup.isSingleResult()) {
-    NamedDecl *Result = Lookup.getAsSingle<NamedDecl>();
-    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 << Lookup.getLookupName()
-          << FixItHint::CreateReplacement(SourceRange(IILoc),
-                                          Result->getNameAsString());
-      else if (DeclContext *DC = computeDeclContext(*SS, false))
-        Diag(IILoc, diag::err_unknown_nested_typename_suggest) 
-          << &II << DC << Lookup.getLookupName() << SS->getRange()
-          << FixItHint::CreateReplacement(SourceRange(IILoc),
-                                          Result->getNameAsString());
-      else
-        llvm_unreachable("could not have corrected a typo here");
+  if (DeclarationName Corrected = CorrectTypo(Lookup, S, SS, 0, 0, CTC_Type)) {
+    if (NamedDecl *Result = Lookup.getAsSingle<NamedDecl>()) {
+      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 << Lookup.getLookupName()
+            << FixItHint::CreateReplacement(SourceRange(IILoc),
+                                            Result->getNameAsString());
+        else if (DeclContext *DC = computeDeclContext(*SS, false))
+          Diag(IILoc, diag::err_unknown_nested_typename_suggest) 
+            << &II << DC << Lookup.getLookupName() << SS->getRange()
+            << FixItHint::CreateReplacement(SourceRange(IILoc),
+                                            Result->getNameAsString());
+        else
+          llvm_unreachable("could not have corrected a typo here");
 
-      Diag(Result->getLocation(), diag::note_previous_decl)
-        << Result->getDeclName();
-      
-      SuggestedType = getTypeName(*Result->getIdentifier(), IILoc, S, SS);
-      return true;
+        Diag(Result->getLocation(), diag::note_previous_decl)
+          << Result->getDeclName();
+        
+        SuggestedType = getTypeName(*Result->getIdentifier(), IILoc, S, SS);
+        return true;
+      }
+    } else if (Lookup.empty()) {
+      // We corrected to a keyword.
+      // FIXME: Actually recover with the keyword we suggest, and emit a fix-it.
+      Diag(IILoc, diag::err_unknown_typename_suggest)
+        << &II << Corrected;
+      return true;      
     }
   }
 
@@ -605,7 +609,7 @@ ObjCInterfaceDecl *Sema::getObjCInterfaceDecl(IdentifierInfo *&Id,
     // Perform typo correction at the given location, but only if we
     // find an Objective-C class name.
     LookupResult R(*this, Id, RecoverLoc, LookupOrdinaryName);
-    if (CorrectTypo(R, TUScope, 0) &&
+    if (CorrectTypo(R, TUScope, 0, 0, false, CTC_NoKeywords) &&
         (IDecl = R.getAsSingle<ObjCInterfaceDecl>())) {
       Diag(RecoverLoc, diag::err_undef_interface_suggest)
         << Id << IDecl->getDeclName()