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"This rule is never matched" warning is not shown if an active pattern is used in match expression #7177

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Bug
#19528
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"This rule is never matched" warning is not shown if an active pattern is used in match expression#7177
Bug
#19528
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AI-thinks-issue-fixedArea-Compiler-PatternMatchingpattern compilation, active patterns, performance, codegenBugImpact-Low(Internal MS Team use only) Describes an issue with limited impact on existing code.
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Backlog
@vasily-kirichenko

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@vasily-kirichenko
vasily-kirichenko
opened on Jul 10, 2019
let _ =
    match obj() with
    | x -> ()
    | _ -> ()
    | _ -> ()

results with proper warnings:

image

However, if an active pattern is used in match expression, there are no warnings at all:

let (|AP|_|) x = Some()

let _ =
    match obj() with
    | AP -> ()
    | _ -> ()
    | _ -> ()

image

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    AI-thinks-issue-fixedArea-Compiler-PatternMatchingpattern compilation, active patterns, performance, codegenBugImpact-Low(Internal MS Team use only) Describes an issue with limited impact on existing code.

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    Bug

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    F# Compiler and Tooling

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