Emit tab warning promptly
p = let x = 4
[tab]y = 5
in 12
produces error: parse error on input ‘y’
and nothing else. The problem is caused by a tab appearing to the user to line up x
with y
but actually placing y
in the wrong column. The user typically will scratch their head and then post a question on StackOverflow. There they'll be told to use -fwarn-tabs
, but ''that option won't help'' (and it's probably already on) because GHC will exit with a parse error before it gets around to giving the warning. I suspect the solution is probably to emit the tab warning in the lexer, but one of the parsing gurus will probably know better.
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | high |
Resolution | Unresolved |
Component | Compiler (Parser) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |