error messages: report a list of missing overrides

[smoothdeveloper]

This is going to be for #4982, right now, it is just a first pass at looking at the code and cleaning a bit without any behaviour change.

I intend to look at noimpl which is the location we report the error.

Instead I plan to make it an accumulator which will raise the error (with the expected message) if more than 10 missing overrides have been encountered, otherwise it will append, and then it will be checked before returning to construct the expected message if needed and raise it.

Please let me know if you see any issue with that plan.

Status:

• main logic implementation
• reorganize error message (and fix their names)
• add exhaustive tests for each variant of the message
• make it green

[vasily-kirichenko]

If mtps is a list, use listSameLength here as well.

[smoothdeveloper]

mmh it is a Typars, which in fact is a list, I'll change it as well.

It would be nice if type aliases in a tooltip were shown at the bottom.

[vasily-kirichenko]

I think there is already an issue/suggestion. It would be easy to implement, the hard part is to decide how to represent it on the tooltip.

[smoothdeveloper]

#3110 revolves around similar topic, in this case it would display:

Typars = Typar list

[smoothdeveloper]

I've added the main logic to CheckDispatchSlotsAreImplemented, few decisions to make:

• do we want to keep the same compiler error number among the variants of the message?
• do we want to reduce the variants of message regarding the one with suggestion related to interface? I believe this should be handled differently by appending another message rather than having a couple of redundant messages with just the end being different (see changes in FSComp.txt)

I'll be working on few code samples to add to the test suite, is fsharpqa\Source\ErrorMessages\MissingOverrides a good location for it?

If you have evil code idea to check I'm not breaking anything or that we have all cases cornered, please share.

Sample output for now:

Microsoft (R) F# Interactive version 10.1.0 for F# 4.1
Copyright (c) Microsoft Corporation. All Rights Reserved.

For help type #help;;

> open System
- open System.IO;;
>
- type IFoo1 =
-   abstract member Foo : t:Type * r:TextReader -> obj
-   abstract member Bar<'t> : TextReader -> 't
-   abstract member Baz<'t> : TextReader -> 't
-
- type Foo1() =
-   interface IFoo1 with
-     member x.Foo(t, reader) = obj()
- ;;

    interface IFoo1 with
  ------------^^^^^

stdin(10,13): error FS0366: No implementation was given for those members:
        'abstract member IFoo1.Bar : TextReader -> 't'
        'abstract member IFoo1.Baz : TextReader -> 't'
 Note that all interface members must be implemented and listed under an appropriate 'interface' declaration, e.g. 'interface ... with member ...'.

> type IFoo2 =
-   abstract member Foo : t:Type * r:TextReader -> obj
-   abstract member Bar<'t> : TextReader -> 't
-   abstract member Baz<'t> : TextReader -> 't
-   abstract member Baz1<'t> : TextReader -> 't
-   abstract member Baz2<'t> : TextReader -> 't
-   abstract member Baz3<'t> : TextReader -> 't
-   abstract member Baz4<'t> : TextReader -> 't
-   abstract member Baz5<'t> : TextReader -> 't
-   abstract member Baz6<'t> : TextReader -> 't
-   abstract member Baz7<'t> : TextReader -> 't
-   abstract member Baz8<'t> : TextReader -> 't
-   abstract member Baz9<'t> : TextReader -> 't
-
- type Foo2() =
-   interface IFoo2 with
-     member x.Foo(t, reader) = obj()
-     ;;

    interface IFoo2 with
  ------------^^^^^

stdin(28,13): error FS0366: No implementation was given for those members (some results omitted):
        'abstract member IFoo2.Bar : TextReader -> 't'
        'abstract member IFoo2.Baz : TextReader -> 't'
        'abstract member IFoo2.Baz1 : TextReader -> 't'
        'abstract member IFoo2.Baz2 : TextReader -> 't'
        'abstract member IFoo2.Baz3 : TextReader -> 't'
        'abstract member IFoo2.Baz4 : TextReader -> 't'
        'abstract member IFoo2.Baz5 : TextReader -> 't'
        'abstract member IFoo2.Baz6 : TextReader -> 't'
        'abstract member IFoo2.Baz7 : TextReader -> 't'
        'abstract member IFoo2.Baz8 : TextReader -> 't'
 Note that all interface members must be implemented and listed under an appropriate 'interface' declaration, e.g. 'interface ... with member ...'.
>

[smoothdeveloper]

I'm not understanding why CI part 3 & 4 fail with this error:

19:59:20 D:\j\w\release_ci_pa---c6929ad7\src\fsharp\MethodOverrides.fs(376,48): error FS0039: The field, constructor or member 'typrelNoImplementationSeveralGivenWithSuggestion' is not defined. Maybe you want one of the following:�   typrelNoImplementationGivenWithSuggestion�   typrelNoImplementationGiven�   typrelCannotResolveImplicitGenericInstantiation�   typrelOverrideImplementsMoreThenOneSlot�   typrelNamedArgumentHasBeenAssignedMoreThenOnce [D:\j\w\release_ci_pa---c6929ad7\src\buildfromsource\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj]
19:59:20 D:\j\w\release_ci_pa---c6929ad7\src\fsharp\MethodOverrides.fs(377,49): error FS0039: The field, constructor or member 'typrelNoImplementationSeveralGiven' is not defined. Maybe you want one of the following:�   typrelNoImplementationGiven�   typrelNoImplementationGivenWithSuggestion�   typrelCannotResolveAmbiguityInDelegate�   typrelOverrideImplementsMoreThenOneSlot�   typrelCannotResolveImplicitGenericInstantiation [D:\j\w\release_ci_pa---c6929ad7\src\buildfromsource\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj]
19:59:20 D:\j\w\release_ci_pa---c6929ad7\src\fsharp\MethodOverrides.fs(378,47): error FS0039: The field, constructor or member 'typrelNoImplementationSeveralTruncatedGivenWithSuggestion' is not defined. Maybe you want one of the following:�   typrelNoImplementationGivenWithSuggestion�   typrelCannotResolveImplicitGenericInstantiation�   typrelTypeImplementsIComparableShouldOverrideObjectEquals�   typrelMemberDoesNotHaveCorrectKindsOfGenericParameters�   typrelTypeImplementsIComparableDefaultObjectEqualsProvided [D:\j\w\release_ci_pa---c6929ad7\src\buildfromsource\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj]
19:59:20 D:\j\w\release_ci_pa---c6929ad7\src\fsharp\MethodOverrides.fs(379,48): error FS0039: The field, constructor or member 'typrelNoImplementationSeveralTruncatedGiven' is not defined. Maybe you want one of the following:�   typrelNoImplementationGivenWithSuggestion�   typrelNoImplementationGiven�   typrelSigImplNotCompatibleConstraintsDiffer�   typrelSigImplNotCompatibleConstraintsDifferRemove�   typrelCannotResolveImplicitGenericInstantiation [D:\j\w\release_ci_pa---c6929ad7\src\buildfromsource\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj]

those are defined in https://github.com/Microsoft/visualfsharp/pull/4983/files#diff-0e57ebf050db850b5efdd7e2cb13e725 and it compiles in part 1 & 2.

[dsyme]

I'm not understanding why CI part 3 & 4 fail with this error:

You have to update the FSComp files at least. See DEVGUIDE.md

    .\build net40
    copy /y src\fsharp\FSharp.Compiler.Private\obj\release\net40\FSComp.* src\buildfromsource\FSharp.Compiler.Private\

[dsyme]

This is looking good, once it's green let's get it merged.

Requested a few minor changes

[smoothdeveloper]

This is green and I think all comments have been addressed.

[smoothdeveloper]

@dsyme thanks for the review, is there a concern about https://github.com/Microsoft/visualfsharp/pull/4983/files#diff-87f5261ee04fbbcd39ff79a83af01e01R270 where we allocate an empty ResizeArray at the top level of CheckDispatchSlotsAreImplemented?

I could change this to a mutable ResizeArray option initialized to None or whatever other suggestion would apply here.

Edit: a list is initialized with empty array and first add to it pushes it to 4 elements, so this is basically not a concern.

[KevinRansom]

@smoothdeveloper,

thanks for this

Kevin