Hat 1.12 Bugs and Limitations
This is a list of some known limitations and bugs in Hat 1.12.
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.
- More details about compile-time problems are listed
here.
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 compare infinite data structures attempting
to generalise across several equations. Use Ctrl-C to kill it.
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.
Hat-trail
- Scrolling sometimes blanks the upper part of the display when
the trace is extended and is deeper than the window.
- If the output is empty, it cannot be selected.
More details about browser bugs and wishes are listed
here.
This page last modified: 15 Mar 2002