YAMLParser: report errors according to provided position

[chfast]

Summary

Function yaml::Scanner::setError() has a Position argument that is never used
and is supposed to provide better information about position of an error.
The change uses Position instead of Current source location.

Alternatively, the Position argument can be removed and the code would be
simplified. Unit tests don't care.

Is there any case where Position is not Current and that information is useful?

[Bigcheese]

lgtm.

[chfast]

Ok, thanks. Any thoughts about the alternative "solution"?

[Bigcheese]

I would prefer the alternative. Just get rid of the parameter.

[chfast]

Please see the alternative https://reviews.llvm.org/D22619.

[chfast]

Ping².

[chfast]

As you are doing something with YAML, can you take a look here?

lib/Support/YAMLParser.cpp

public:
   Token getNext();
 
   void printError(SMLoc Loc, SourceMgr::DiagKind Kind, const Twine &Message,
                   ArrayRef<SMRange> Ranges = None) {
     SM.PrintMessage(Loc, Kind, Message, Ranges, /* FixIts= */ None, ShowColors);
   }
 
   void setError(const Twine &Message, StringRef::iterator Position) {
-    if (Current >= End)
-      Current = End - 1;
+    if (Position >= End)
+      Position = End - 1;
 
     // Don't print out more errors after the first one we encounter. The rest
     // are just the result of the first, and have no meaning.
     if (!Failed)
-      printError(SMLoc::getFromPointer(Current), SourceMgr::DK_Error, Message);
+      printError(SMLoc::getFromPointer(Position), SourceMgr::DK_Error, Message);
     Failed = true;
   }
 
   void setError(const Twine &Message) {
     setError(Message, Current);
   }
 
   /// @brief Returns true if an error occurred while parsing.