[doc parsing]: don't attempt to fix single character

commands (\t \n are common). \\ rdar://12381408 


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181517 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AST/CommentCommandTraits.cpp

@@ -49,6 +49,10 @@ HelperTypoCorrectCommandInfo(SmallVectorImpl<const CommandInfo *> &BestCommand,
   const unsigned MaxEditDistance = 1;
   unsigned BestEditDistance = MaxEditDistance + 1;
   StringRef Name = Command->Name;
+  // Don't attempt trying to typo fix single character commands.
+  // \t and \n are very common
+  if (Name.size() <= 1)
+    return;
   
   unsigned MinPossibleEditDistance = abs((int)Name.size() - (int)Typo.size());
   if (MinPossibleEditDistance > 0 &&

test/Sema/warn-documentation-fixits.cpp

@@ -67,6 +67,9 @@ int FooBar();
 /// \fooba bbb IS_DOXYGEN_END
 int gorf();
 
+/// \t bbb IS_DOXYGEN_END
+int Bar();
+
 // CHECK: fix-it:"{{.*}}":{5:12-5:22}:"a"
 // CHECK: fix-it:"{{.*}}":{9:12-9:15}:"aaa"
 // CHECK: fix-it:"{{.*}}":{13:13-13:23}:"T"