Fix get_op in the case of an unambiguous record selector (#13132)

Test Plan: validate

Reviewers: simonpj, austin, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D2985

GHC Trac Issues: #13132

compiler/rename/RnTypes.hs

@@ -1227,6 +1227,7 @@ get_op :: LHsExpr Name -> Name
 -- See RnExpr.rnUnboundVar
 get_op (L _ (HsVar (L _ n)))   = n
 get_op (L _ (HsUnboundVar uv)) = mkUnboundName (unboundVarOcc uv)
+get_op (L _ (HsRecFld (Unambiguous _ n))) = n
 get_op other                   = pprPanic "get_op" (ppr other)
 
 -- Parser left-associates everything, but

testsuite/tests/rename/should_compile/T13132.hs

+module Bug where
+
+newtype ContT r m a = ContT { runContT :: (a -> m r) -> m r }
+
+foo bar baz = (`runContT` bar.baz)

testsuite/tests/rename/should_compile/all.T

@@ -245,3 +245,4 @@ test('T12127',
 test('T12533', normal, compile, [''])
 test('T12597', normal, compile, [''])
 test('T12548', normal, compile, [''])
+test('T13132', normal, compile, [''])