Summary: In the [expr.sub] p1, we can read that for a given E1[E2], E1 is sequenced before E2.
Patch by Mateusz Janek.
Reviewers: rsmith, Rakete1111
Reviewed By: rsmith, Rakete1111
Subscribers: riccibruno, lebedev.ri, Rakete1111, hiraditya, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D50766
llvm-svn: 350874