Do not infer record fields if the LRH type is already known

[vasily-kirichenko]

This fixes #3574 and #3576

[KevinRansom]

Looks good.

[vasily-kirichenko]

wait

[vasily-kirichenko]

OK, it's really great :) (I tried to use

match adhoctDotSearchAccessible with 
    // If the type is already known, we should not try to lookup a record field
    | Exception _ when isRecdTy ncenv.g typ -> 

but it broke everything).

[vasily-kirichenko]

@dotnet-bot test this please

[KevinRansom]

@vasily-kirichenko breaking everything is a small price to pay for It's great ....

[vasily-kirichenko]

The current version seems to work OK.

I'm not sure if this is the right solution because Don suggested to use isNominalTy typ || isRecordTy #3576 (comment)

[dsyme]

@vasily-kirichenko As I explained in #3576 (comment) "isRecordTy" is not enough. The type can be a type variable too (e.g. isTyparTy, or, not isNominalTy is enough)

[dsyme]

@vasily-kirichenko Yes, what you have now should be enough

[cartermp]

@dotnet-bot test Windows_NT Release_ci_part2 Build please

[vasily-kirichenko]

it's ready

[dsyme]

Minor nit: this is odd code formatting for the compiler. We would normally use

    if X then 
        Y
    else
        match Z with 

or

    if X then Y else
    match Z with 

[dsyme]

I will mark as approved, but we should normally always add a test for this kind of change. Add it in tests\fsharp\typecheck\sigs

[vasily-kirichenko]

Done.

[vasily-kirichenko]

@dotnet-bot test this please