Undeclared variable in cmm reports as panic
In CMM code, if one makes an assignment to a variable that's not been declared, the compiler panics, in addition to reporting an almost sensible error message.
Here's code to make it happen:
testingbug
{
var = 1;
}And here's the output it causes:
ghc-6.9.20080305: panic! (the 'impossible' happened)
(GHC version 6.9.20080305 for x86_64-unknown-linux):
CmmParse: var not a register
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabugI see two problems here:
- As the output notes, the compiler should not panic just because the user fed it noticeably bad code. It should just report the underlying message, with a line/column reference to the offending code.
- The error message should quote the variable name about which it's complaining. When I initially discovered this, the variable name in question was
data, and that was rather confusing.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 6.9 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |