Crash when compiling with nims files - only on v0.19.2

[genotrance]

Consider three files:

# a.nim
echo "Hello"

# config.nims
switch("d", "ABC")

# a.nims
switch("d", "DEF")

When compiling a.nim, nim crashes. This is only seen on 0.19.2, not on 0.19.0 or on devel.

> nim c a.nim
Hint: used config file 'C:\Users\gt\.choosenim\toolchains\nim-0.19.2\config\nim.cfg' [Conf]
Hint: used config file 'C:\Dropbox\Private\github\nimterop\config.nims' [Conf]
???(0, 0) Error: internal error: n is not nil
No stack traceback available
To create a stacktrace, rerun compilation with ./koch temp c <file>

Delete one of the nims files and it works again.

I'm using config.nims for global flags and a.nims for a define that only applies in compiled executable.

[Araq]

@timotheecour is the bugfix/commit marked with [backport]?

[timotheecour]

no idea, i just added fixed in devel because it works in devel; idk if it's 1 commit or more, or it got fixed by chance as part of another commit; the good news is our git history is now quite linear so git bisect could help to identify it
(all commits since 2018-12-19 10:03 +0100 Andreas Rumpf M─┐ Merge pull request #9959 from nc-x/better-error-message)

[narimiran]

git bisect could help to identify it

I did git bisect on version-0-19 branch and it spit out 41e2f6b as a first bad commit ;)

[narimiran]

I just confirmed that reverting that commit would fix this bug in version-0-19 branch.

[timotheecour]

but that fixed a regression itself:
fix #9264 regression (#9265)

so would probably need to backport stuff like #9259 (this PR should have all the context, including the revert of #8590 done in #9265)

[narimiran]

so would probably need to backport stuff like #9259

You're right, backporting that fixed this issue.

I just pushed that to version-0-19, so the fix will be part of v0.19.4 — this can be closed now.