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Incorrect error/warning position ranges #1801
Description
Activity
ShadowedName
If you do something like
foo = \baz -> case baz of Just baz -> 42 Nothing -> 12
It returns the position of the entire top level expression, which can require some hunting. It should point to where the shadowed name was bound.
Also, interestingly, if I change it to:
foo' baz = case baz of Just baz -> 42 Nothing -> 12
No warning is generated.
WildcardInferredType
The position ranges over the entire type declaration. It should point to a specific wildcard, otherwise its confusing if you have multiple wildcards.
UnknownValue
Given:
module Test.Foo where foo n = n + 1
It reports the error as
Error found: in module Test.Foo at /Users/nathan/Sites/purescript/purescript-psa/test/Foo.purs line 3, column 9 - line 3, column 13 Unknown value (+)The correct start range would be line 3, column 11.
Reacted by Alexander ThiemannErrorParsingModule
Given:
module Test.Foo where improt Prelude import Bar
It reports the error as
Error found: at /Users/nathan/Sites/purescript/purescript-psa/test/Foo.purs line 4, column 1 - line 4, column 1 Unable to parse module: unexpected "import" expecting binder or indentationWhich is an empty span.
NoInstanceFound
module Test where import Prelude type Foo = {foo::Int} foo :: Foo -> Foo -> Boolean foo x y = x == yError found: in module Test at Test.purs line 5, column 1 - line 6, column 1 No type class instance was found for Prelude.Eq { foo :: Int } in value declaration foo See https://github.com/purescript/purescript/wiki/Error-Code-NoInstanceFound for more information, or to contribute content related to this error.Reacted by Ryan RempelInfiniteType
module InfiniteType where import Prelude (map) foo = "wat" where woo = "woo" wat x = map (\k -> wat k x)
in module InfiniteType at InfiniteType.purs line 6, column 3 - line 7, column 3 An infinite type was inferred for an expression: _0 _1 while trying to match type _0 _1 with type _1 while inferring the type of let woo = "woo" wat = \x -> ... in "wat" in value declaration foo where _0 is an unknown type _1 is an unknown typeWhich is the definition of
woo(it'swatthat gives the error). If you do this at the top level it reports no error location.CannotDerive
doesn't have positionderive instance foo :: Generic {foo::Int}Error found: Cannot derive a type class instance for Data.Generic.Generic { foo :: Int } See https://github.com/purescript/purescript/wiki/Error-Code-CannotDerive for more information, or to contribute content related to this error.DuplicateModuleName
doesn't have position
Main.pursmodule Main whereMain2.purs
module Main whereError found: Module Main has been defined multiple times. See https://github.com/purescript/purescript/wiki/Error-Code-DuplicateModuleName for more information, or to contribute content related to this error.CycleInModules
doesn't have position
Main.pursmodule Main where import TestTest.purs
module Test where import MainError found: There is a cycle in module dependencies in these modules: Main Test See https://github.com/purescript/purescript/wiki/Error-Code-CycleInModules for more information, or to contribute content related to this error.UnknownImportDataConstructor
doesn't have positionmodule Test where type Foo = Foo IntError found: in module Test Module Test does not export data constructor Foo for type Foo See https://github.com/purescript/purescript/wiki/Error-Code-UnknownImportDataConstructor for more information, or to contribute content related to this error.TypesDoNotUnify
If the
returntype of a do block is incorrect, the error spans over the entire block.module DoTest where import Prelude import Data.Maybe foo :: Maybe String foo = do x <- Just 42 y <- Just 12 pure y
[1/1 TypesDoNotUnify] src/DoError.purs:7:7 v 7 foo = do 8 x <- Just 42 9 y <- Just 12 10 pure y ^ Could not match type Int with type String while trying to match type Maybe _0 with type Maybe String while checking that expression (bind (Just 42)) (\$1 -> case $1 of x -> ... ) has type Maybe String in value declaration foo where _0 is an unknown typeUnknownDataConstructor
module Test where data Foo = Foo Int foo = Foo BarError found: in module Test at Test.purs line 4, column 7 - line 4, column 11 Unknown data constructor Bar See https://github.com/purescript/purescript/wiki/Error-Code-UnknownDataConstructor for more information, or to contribute content related to this error.should be
line 4, column 11 - line 4, column 1322 remaining items
WildcardInferredTypeis done (also listed twice above)7 main :: forall eff. Eff (console :: CONSOLE | eff ) _ ^UnknownName- it seems this example has a different error code but the same error position (note the same occurs withfoo n = add n 1, the wording is different)[1/1 UnknownName] src/Foo.purs:10:9 10 foo n = n + 1 ^^^^^ Unknown operator (+)- added a commit that references this issue
on Nov 11, 2016 - added a commit that references this issue
on Nov 16, 2016 [1/8 CannotFindDerivingType] Cannot derive a type class instance, because the type declaration for VarMapValue could not be found.I've started working on an AST representation in which source span annotations will be necessary everywhere, which should help a lot here. It's going to take a while though, since it's a big change.
Reacted by Harry Garrood and Nathan FaubionNot sure if this goes here or not, but thought I'd post. I can open a new ticket if so.
If you leave out a comma when defining a type alias, the compiler things there is a kind error.
type Asset = { name :: String list :: Array String } Unknown kind ArrayReacted by Vance PalacioTypesDoNotUnify
When a type mismatch arises as a result of a use of the record update syntax
r { x = y }whereris not a record, the span seems to be larger than necessary:makeRecord x = { x, y: 0 } eg = case unit of _ -> makeRecord 0 { y = 1 }Note that for this to typecheck you would need to write
(makeRecord 0) { y = 1 }. The source span for this error is currently the entireegdeclaration.TypesDoNotUnify
When a record field does not match, the error span sometimes covers the entire record literal. I've found that this problem is more likely to arise in the presence of type applications, i.e. having
Array StringversusMaybe Stringseems more likely to result in a bad error span than sayStringversusInt.module Main where import Prelude import Data.Maybe eg :: { foo :: String, bar :: Array Int } eg = { foo: "hi" , bar: Just "hi" }I've checked all the outstanding test cases, and the list is now up to date as of the v0.14 release candidates. Remaining items behave as follows:
TransitiveExportError: spans the entire moduleMissingFFIImplementations: spans the entire moduleKindsDoNotUnify: highlights a relevant token, but not the most intuitive/helpful onesTypesDoNotUnify: highlights the wrong part of thedoblock
I gave
CycleInModulescredit because it now highlights the module header and imports block. Conceivably it could zero in on the problematic import(s) but I don't think that's always possible in the case of complex cycles, in which case I'm not sure what the ideal behavior would be.Is the
affects-v0.14.0label new? What does it mean exactly?It means I've confirmed the bug is still present in 0.14. Right now it's functioning as a checklist as I go through our list of 60 open bugs and look for anything that can be trivially closed; going forward, my thought was that it'll get replaced by
affects-v0.15.0etc. on bugs that continue to be confirmed on newer versions of PS, and thus serve as a staleness indicator for the next person doing housekeeping. (If you think this is a bad idea, I can stop using the label.)Ah, I see, thanks. Not at all, that sounds great - thank you for doing this!
I'm working on a frontend for psc that prints original source ranges, so it makes it very easy to spot which errors have incorrect position reporting. This issue is to catalog all those we find so we don't have to make separate issues for them.
Edit (@paf31) Here is a list of all errors listed here. Let's check them off as they get fixed:
NoInstanceFoundWildcardInferredTypeTransitiveExportErrorUnknownTypeUnknownDataConstructorUnknownImportDataConstructorUnknownValueKindsDoNotUnifyTypesDoNotUnifyCycleInModulesShadowedNameInfiniteTypeDuplicateModuleNameCannotFindDerivingTypeMissingFFIImplementationsCannotDerive