Fix tyvar scoping within class SPECIALISE pragmas

Type variables from class/instance headers scope over class/instance
method type signatures, but DO NOT scope over the type signatures in
SPECIALISE and SPECIALISE instance pragmas.

The logic in GHC.Rename.Bind.rnMethodBinds correctly accounted for
SPECIALISE inline pragmas, but forgot to apply the same treatment
to method SPECIALISE pragmas, which lead to a Core Lint failure with
an out-of-scope type variable. This patch makes sure we apply the same
logic for both cases.

Fixes #22913

2 files changed, 11 insertions, 0 deletions

diff --git a/testsuite/tests/rename/should_compile/T22913.hs b/testsuite/tests/rename/should_compile/T22913.hs
new file mode 100644
index 0000000000..a43ee28a9d
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T22913.hs
@@ -0,0 +1,10 @@
+module T22913 where
+
+class FromSourceIO a where
+    fromSourceIO :: a
+instance FromSourceIO (Maybe o) where
+    fromSourceIO = undefined
+    {-# SPECIALISE INLINE fromSourceIO :: Maybe o #-}
+ -- This SPECIALISE pragma caused a Core Lint error
+ -- due to incorrectly scoping the type variable 'o' from the instance header
+ -- over the SPECIALISE pragma.
diff --git a/testsuite/tests/rename/should_compile/all.T b/testsuite/tests/rename/should_compile/all.T
index 19401582dd..673cdf8c78 100644
--- a/testsuite/tests/rename/should_compile/all.T
+++ b/testsuite/tests/rename/should_compile/all.T
@@ -199,3 +199,4 @@ test('T22513f', normal, compile, ['-Wterm-variable-capture'])
 test('T22513g', normal, compile, ['-Wterm-variable-capture'])
 test('T22513h', normal, compile, ['-Wterm-variable-capture'])
 test('T22513i', req_th, compile, ['-Wterm-variable-capture'])
+test('T22913', normal, compile, [''])