[EMAIL PROTECTED] writes:
> A typo which should cause a type error produces instead
> an Hugs 1.4 internal error:
>
> data C = C { p :: Int}
> a c = C (p = p c) -- typo: () instead of {}
>
> --------------------------------------
> Dependency analysis
> INTERNAL ERROR: in depExpr
> --------------------------------------
Actually, it should cause a parse error since this isn't legal Haskell
syntax - but it is legal TREX syntax. (TREX - Typed Records with
EXtensions - are pretty cool but they're off by default.)
Here's a patch which catches every use of TREX-specific syntax and
prints a mildly useful error message instead.
diff -r1.16 parser.y
45a46,48
> #if !TREX
> static Void local noTREX Args((String));
> #endif
385c388,394
< lacks : varid1 '\\' varid1 {$$ = gc3(ap(mkExt(textOf($3)),$
1));}
---
> lacks : varid1 '\\' varid1 {
> #if TREX
> $$ = gc3(ap(mkExt(textOf($3)),$1));
> #else
> noTREX("a type context");
> #endif
> }
428c437
< $$ = gc3(NIL);
---
> noTREX("a type");
630c639,645
< vfield : qvarid '=' exp {$$ = gc3(ap(mkExt(textOf($1)),$
3));}
---
> vfield : qvarid '=' exp {
> #if TREX
> $$ = gc3(ap(mkExt(textOf($1)),$3));
> #else
> noTREX("an expression");
> #endif
> }
958a974,982
>
> #if !TREX
> static Void local noTREX(where)
> String where; {
> ERRMSG(row) "Attempt to use Typed Records with Extensions\nwhile parsing %
s. This feature is disabled in this build of Hugs.",
> where
> EEND;
> }
> #endif
[The rule for making parser.c from parser.y is commented out in the
Makefile since we assume that you don't have a working yacc on your
system. On PCs, this is a fairly safe assumption since neither byacc
nor bison produce working parser.c's.]
It'd be nicer to just disable the syntax rules altogether - but then you
have to preprocess the grammar which doesn't work.
> This happens on a PC and on a Sun4 running SunOS 4.1.3,
> but not on a Sun running 5.5.1.
Yoiks. I can't imagine why it wouldn't show up on Solaris. Can you
check again?
Alastair
