Bug #:

Submitted by:
Reviewed by:
- Added type checking to Sema::ParseReturnStmt (still under construction).
- Improved Expr::isLvalue() and Expr::isModifiableLvalue() to return more
info. Used the info in Sema::CheckAssignmentOperands() to produce more
descriptive diagnostics. Added FIXME to other clients of isLvalue()/etc.
- Added a SourceLocation slot to MemberExpr...changed the implementation
of getSourceRange().
- Added getResultType() helper to FunctionDecl.
- Changed many Diag calls to use the SourceRange support (now that it's
a big hit...we better milk it:-).

llvm-svn: 39501