This page collects tickets that Simon PJ is interested in, so that he remembers them

Performance

• #2253: NCG could do better. Look at this when John D’s ncg is working
• #2762: Arity analysis
• #1434: Slow conversion Double to Int
• #2439: Strict dictionaries
• #2002: Very slow compilation. (There is linear stack growth with depth of linear list literal, which we think is ok, but it still should not be so slow.) Needs profiling
• #2132: Optimise nested comparisons: if you know x>0 then you know x>=1 etc. Maybe a special pass that knows about arithmetic?
• #783: SRTs getting big
• #1969: quadratic behaviour in the specialiser
• #1216: array indexing, inlining/arity bug
• #149: float-out/CSE
• #2078: INLINing improvement; ask Christian.Maeder@… to see if it improves CASL
• #2463: mall change makes a big change to inlining (of a record) and performance
• #2289, 2387:(a) cheap check at start of case alternatives, (b) nested CPR analysis
• #1818 code size regression Simonmar
• #2092 Possible quadratic-sized Eq instances. Does it really go quadratic, or does the join-point inlining machinery prevent it? Simonmar
• #2255 Improve SpecConstr for free variables
• #2374 SAT and MutableByteArray? Max?
• #2420 Inlining of class methods infelicity (odd rather than bad)
• #
• #Bugs
• #2202 Typechecker loop, caused by normalization of equalities. There’s a related bug from Bryan Donlan in the same ticket. Manuel
• #1870 Panic compiling regex-tdfa-0.93
• #1148, 2267, 1074 “Unused import” warnings should be generated from RdrNames?
• #2193 Bad error message with impredicative types
• #2182 GHCi session retains instance after removing a module from scope
• #2152 Bogus inlining of foregn import. Arises from seeing through a NOINLINE in exprIsConApp_maybe
• #1241 Lifting the Coverage Condition for functional dependencies isn’t the Right Thing Manuel
• #2256 Incomplete inference due to lack of quantification over implication constraints.
• #
• #Also, see “BUG WARNING” in TcSimplify? line 717 or thereabouts. fdPredsOfInsts is returning preds that mention quantified variables, which is quite wrong Manuel
• #2219 GADT refinement fails to refine type variable Manuel
• #2239 Lack of improvement with type functions Manuel
• #1954 Incorrect “defined but not used” msg
• #
• #Features
• #788 Class aliases
• #2086 Require bang patterns on unlifted let-bindings
• #2648 Report out of date interface files robustly
• #2599 Better error message for non-rigid types
• #2588 Better error message about ‘forall’
• #2600 Bind type variables in RULES
• #2595 Record update for existentials
• #2442 Better error message heuristics for “not in scope” Max B’s patch
• #2340 Better TH error recovery. Easy to do; change to signature of qRecover.
• #1930 Infix type operators: a+b.
• #2360 Better location info in occurs-check message.
• #1856 Better error message for mutually recursive modules
• #1928 Confusing type error message (Claus makes suggestions)
• #2534 Another confusing type error message
• #1441 Generate local info for ‘undefined’. Implicit location parameters in general
• #1475 Allow TH to generate import declarations
• #2135 Warn when exporting a function whose type mentions a type constructor defined locally but not itself exported
• #2526 Add -fwarn-missing-export-signatures
• #2119 Explicitly importing deprecated symbols should generate deprecation warnings
• #2116 GHCi should load as much of the module as it can
• #2207 Load interfaces for GHC.* even without -O
• #1231 Better deprecations