Arrows: correctly query arrow methods (#17423)

Consider the following code:

    proc (C x y) -> ...

Before this patch, the evidence binding for the Arrow dictionary was
attached to the C pattern:

    proc (C x y) { $dArrow = ... } -> ...

But then when we desugar this, we use arrow operations ("arr", ">>>"...)
specialised for this arrow:

    let
        arr_xy = arr $dArrow -- <-- Not in scope!
        ...
    in
        arr_xy (\(C x y) { $dArrow = ... } -> ...)

This patch allows arrow operations to be type-checked before the proc
itself, avoiding this issue.

Fix #17423

3 files changed, 1 insertions, 1 deletions

diff --git a/testsuite/tests/gadt/T17423.hs b/testsuite/tests/arrows/should_compile/T17423.hs
index 35023f0612..35023f0612 100644
--- a/testsuite/tests/gadt/T17423.hs
+++ b/testsuite/tests/arrows/should_compile/T17423.hs
diff --git a/testsuite/tests/arrows/should_compile/all.T b/testsuite/tests/arrows/should_compile/all.T
index 279dd109dd..b47cea0538 100644
--- a/testsuite/tests/arrows/should_compile/all.T
+++ b/testsuite/tests/arrows/should_compile/all.T
@@ -16,3 +16,4 @@ test('T5283', normal, compile, [''])
 test('T5267', expect_broken(5267), compile, [''])
 test('T5022', normalise_fun(normalise_errmsg), compile, [''])
 test('T5333', normal, compile, [''])
+test('T17423', normal, compile, [''])
diff --git a/testsuite/tests/gadt/all.T b/testsuite/tests/gadt/all.T
index 05ec39f18e..225d8e8650 100644
--- a/testsuite/tests/gadt/all.T
+++ b/testsuite/tests/gadt/all.T
@@ -119,6 +119,5 @@ test('T14808', normal, compile, [''])
 test('T15009', normal, compile, [''])
 test('T15558', normal, compile, [''])
 test('T16427', normal, compile_fail, [''])
-test('T17423', expect_broken(17423), compile_and_run, [''])
 test('T18191', normal, compile_fail, [''])
 test('SynDataRec', normal, compile, [''])