Hat 1.10 Bugs and Limitations


This is a list of some known limitations and bugs in Hat 1.10. Please mail nhc-bugs@haskell.org to report any other problems you find.

Compile-time problems:

Type variables of higher kinds have only limited support.
Libraries Time and Locale are missing.
Rarely, the compiler fails with heap overrun.
Very rarely, the compiler fails with No match in _dCaf.

Run-time problems:

Programs that exhaust memory fail with no trace.
Strictness annotations in data type definitions lose their effect.

Problems with viewing a trace

General

Records are not traced at source level.
List comprehensions are not traced at source level.
Monadic do expressions are not traced at source level.
Some numeric expressions are not traced at source level.
Super-saturated applications are not shown correctly.
Traces involving pattern bindings may be incomplete.

Hat-observe

Hat-observe cannot show infinite data structures.

Hat-detect

Only useable for computations that produce faulty output, not for computations that abort with an error message or are interrupted.
Does not work correctly for programs that read input.
It cannot show infinite data structures.

Hat-trail

Scrolling sometimes resets when trace is extended and is deeper than trace window.
If the output is empty, it cannot be selected.
In script playback, folding away trace sections doesn't work.

This page last modified: 18 Oct 2001