clang frontend crash due to an exponential complexity of typo corrector

[llvmbot]

Bugzilla Link	44580
Version	unspecified
OS	All
Attachments	typos.cpp from description
Reporter	LLVM Bugzilla Contributor
CC	@dwblaikie,@DougGregor,@zygoloid,@Weverything

Extended Description

Compiling typos.cpp ends with an "LLVM ERROR: out of memory"

typos.cpp is a very simple file with n=10 int definitions and a function call with n arguments.
When clang analyzes this file it tries to correct typos in it. In order to do this it calls method clangSema::SemaExprCXX.cpp::CheckAndAdvanceTypoExprCorrectionStreams

The problem is that amount of calls is around 8^(n-1), which leads to a crash or infinitely long waiting time.

[Endilll]

Still hanging as of post-17 trunk: https://godbolt.org/z/4PfT54sjG

[llvmbot]

@llvm/issue-subscribers-clang-frontend

[AaronBallman]

This issue is fixed now that we've removed delayed typo correction in 9eef4d1