change FullSourceLoc to have a *const* SourceManager&, eliminating
a const_cast.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101940 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/TextDiagnosticPrinter.cpp b/lib/Frontend/TextDiagnosticPrinter.cpp
index f2b16a4..28bb17a 100644
--- a/lib/Frontend/TextDiagnosticPrinter.cpp
+++ b/lib/Frontend/TextDiagnosticPrinter.cpp
@@ -282,7 +282,7 @@
 void TextDiagnosticPrinter::EmitCaretDiagnostic(SourceLocation Loc,
                                                 SourceRange *Ranges,
                                                 unsigned NumRanges,
-                                                SourceManager &SM,
+                                                const SourceManager &SM,
                                                 const FixItHint *Hints,
                                                 unsigned NumHints,
                                                 unsigned Columns) {