switch a fixme to an assert.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40717 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/SourceLocation.h b/include/clang/Basic/SourceLocation.h
index 2ebed47..420d501 100644
--- a/include/clang/Basic/SourceLocation.h
+++ b/include/clang/Basic/SourceLocation.h
@@ -49,8 +49,7 @@
     
     // FIXME: Find a way to handle out of FileID bits!  Maybe MaxFileID is an
     // escape of some sort?
-    if (FileID >= (1 << FileIDBits))
-      FileID = (1 << FileIDBits)-1;
+    assert(FileID < (1 << FileIDBits) && "Out of fileid's");
     
     L.ID = (FileID << FilePosBits) | FilePos;
     return L;