Pattern synonyms bind variables out of scope

Wasn't sure what to call this ticket:

{-# Language PatternSynonyms #-}

pattern XInstrProxy :: (Bool -> Bool) -> a
pattern XInstrProxy not <- _

This works fine, is it intended? It came as some surprise to me when I was renaming type variables only to find it still working even though I hadn't changed the variable in the ViewPattern

import Data.Tagged

pattern XInstrProxy proxy <- ((\(Proxy::Proxy descr) -> Proxy::Proxy (XInstr descr)) -> ty) 

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	mpickering
Operating system
Architecture

changed weight to 5

added Tbug Trac import labels

Trac metadata

Trac field	Value
TypeOfFailure	OtherFailure → InvalidProgramAccepted

assigned to @mpickering

Trac metadata

Trac field	Value
Differential revisions	- → D3377

changed milestone to %8.2.1

added 1 deleted label

removed 1 deleted label

mentioned in commit d819e416

closed

This is fixed by #13470 (closed).

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed
Test case	- → patsyn/should_fail/T13470

mentioned in issue #13969 (closed)

added PatternSynonyms label

added Pnormal label