WIP: Improve error reporting: Recursive async functions

[forki]

• fixes Improve error reporting: Recursive async functions #1170

This does two things:

• We don't talk about "infinite types" any more and just talk about unification issues.
• In the case of return we give advice to use return!

[dsyme]

Will misuses of "yield" now report an error about "return"? Test cases for that?

[forki]

Can we distinguish the two?

[forki]

uh just saw I didn't commit any of my tests. oups.

[forki]

@dsyme do you know a sample that would create infinite types using yield?!
And I think the code is only triggered from with CE that are not seq

[forki]

@Tarmil gave the following code sample.

So indeed we have a false positive. Adding as test case and trying to fix it.

[forki]

/// F# syntax: yield expr 
/// F# syntax: return expr 
/// Computation expressions only
| YieldOrReturn   of (bool * bool) * SynExpr * range

@dsyme should we split that in ast.fs? Maybe in separate PR?

[forki]

so that's good.

[forki]

I leave

for another day ;-)

[dsyme]

Awesome. The code looks just fine.

I do still wonder if we should say something more than "types can't be unified", given we know there is a specific reason for this (one type would be included in the other, the types would be infinite etc.).

[forki]

yes we can improve on the wording. I just think we should avoid to talk about "infinite types" here. Even if this is the correct term it's probably a term that only very few people know. maybe we could use wording that talks about an "infinite loop while unifying". That is maybe a little less correct but I assume everyone has already seen an infinite loop.

[dsyme]

@forki Any idea why AppVeyor is no longer showing in the list of CI builds?

[forki]

I think I saw a comment from @otawfik-ms that he removed the appveyor trigger.

[dsyme]

@forki Oh, ok.

@otawfik-ms can you confirm?

I don't mind as long as what we have is reliable - I'm just a creature of habit and I'm used to AppVeyor. I haven't learned Jenkins yet, but I'll start.

@otawfik-ms Can you make sure either @forki or myself or both have admin access on Jenkins please? And @KevinRansom too. Thanks.

[OmarTawfik]

@dsyme @forki Jenkins is the main CI server for all dotnet projects now. Roslyn/other dotnet projects will be using it, with much better support for updates, parallel execution, and it is much faster (we are running all tests in CI now).
However, we will keep the appveyor script because a few community members suggested that they still want to run appveyor on their private forks for CI.

[forki]

just for fun, this is what elm gives for something similar:

Source

[KevinRansom]

ci_part2 failed:

http://dotnet-ci.cloudapp.net/job/Microsoft_visualfsharp/job/master/job/release_ci_part2_windows_nt_prtest/348/consoleText

+++ Warnings (ReturnInsteadOfReturnBang.fs) +++
Microsoft (R) F# Compiler version (private)
Copyright (c) Microsoft Corporation. All Rights Reserved.
(4,32): error FS0001: Type mismatch. Expecting a
    ''a'    
but given a
    'Async<'a>'    
The types ''a' and 'Async<'a>' cannot be unified.

Consider using 'return!' instead of 'return'.

*** The following necessary lines were never matched:
*** \(4,32\):.+error FS0001:.+.+Consider using 'return!' instead of 'return'.*


*** The following necessary lines were incorrectly matched:

Unexpected Compiler Output 
FAIL
+++ Warnings (YieldInsteadOfYieldBang.fs) +++
Microsoft (R) F# Compiler version (private)
Copyright (c) Microsoft Corporation. All Rights Reserved.
(7,30): error FS0001: Type mismatch. Expecting a
    ''a'    
but given a
    ''a list'    
The types ''a' and ''a list' cannot be unified.

Consider using 'yield!' instead of 'yield'.

*** The following necessary lines were never matched:
*** \(7,30\):.+error FS0001:.+.+Consider using 'yield!' instead of 'yield'.*


*** The following necessary lines were incorrectly matched:

Unexpected Compiler Output 
FAIL







Error: 'RunTests.cmd release fsharpqa ' failed

[forki]

Yeah I'm trying like crazy to find the correct Regex. I think I tried like
15 times now
On May 18, 2016 7:55 PM, "Kevin Ransom (msft)" [email protected]
wrote:

ci_part2 failed:

http://dotnet-ci.cloudapp.net/job/Microsoft_visualfsharp/job/master/job/release_ci_part2_windows_nt_prtest/348/consoleText

+++ Warnings (ReturnInsteadOfReturnBang.fs) +++
Microsoft (R) F# Compiler version (private)
Copyright (c) Microsoft Corporation. All Rights Reserved.
(4,32): error FS0001: Type mismatch. Expecting a
''a'
but given a
'Async<'a>'
The types ''a' and 'Async<'a>' cannot be unified.

Consider using 'return!' instead of 'return'.

*** The following necessary lines were never matched:
** (4,32):.+error FS0001:.+.+Consider using 'return!' instead of 'return'.

*** The following necessary lines were incorrectly matched:

Unexpected Compiler Output
FAIL
+++ Warnings (YieldInsteadOfYieldBang.fs) +++
Microsoft (R) F# Compiler version (private)
Copyright (c) Microsoft Corporation. All Rights Reserved.
(7,30): error FS0001: Type mismatch. Expecting a
''a'
but given a
''a list'
The types ''a' and ''a list' cannot be unified.

Consider using 'yield!' instead of 'yield'.

*** The following necessary lines were never matched:
** (7,30):.+error FS0001:.+.+Consider using 'yield!' instead of 'yield'.

*** The following necessary lines were incorrectly matched:

Unexpected Compiler Output
FAIL

Error: 'RunTests.cmd release fsharpqa ' failed

—
You are receiving this because you were mentioned.
Reply to this email directly or view it on GitHub
#1180 (comment)

[forki]

@KevinRansom @enricosada any ideas why it doesn't match?

[forki]

this is seriously driving me nuts. I can't see the error in my regex.

[enricosada]

try multiple <Expect with single parts

//<Expects status="Error" span="(7,30)" id="FS0001">.Type mismatch. Expecting a.+''a'.+but given a.+''a list'.+The types ''a' and ''a list' cannot be unified. Consider using 'yield!' instead of 'yield'.*</Expects>

also span="(7,30)" is ok? i think the error message has more characters

[forki]

That's where it starts. Tbh I only want to check for the "consider" part.
On May 23, 2016 16:46, "Enrico Sada" [email protected] wrote:

try multiple <Expect with single parts

//.Type mismatch. Expecting a.+''a'.+but given a.+''a list'.+The types ''a' and ''a list' cannot be unified. Consider using 'yield!' instead of 'yield'.*

also span="(7,30)" is ok? i think the error message has more characters

—
You are receiving this because you were mentioned.
Reply to this email directly or view it on GitHub
#1180 (comment)

[KevinRansom]

@forki I took care of the error messages:
4cce423

[forki]

Thanks so much Kevin. Didn't understand what was wrong.
On May 23, 2016 10:06 PM, "Kevin Ransom (msft)" [email protected]
wrote:

@forki https://github.com/forki I took care of the error messages:

4cce423
4cce423

—
You are receiving this because you were mentioned.
Reply to this email directly or view it on GitHub
#1180 (comment)