Expression evaluator doesn't work in value-dependent types, so ensure that the precondition it asserts holds. This fixes https://bugs.llvm.org/show_bug.cgi?id=42532 Differential Revision: https://reviews.llvm.org/D64409 llvm-svn: 365490
Patch by Emilio Cobos Álvarez! See https://reviews.llvm.org/D26788 llvm-svn: 288438
rdar://24091595 llvm-svn: 257968