Make implication tidying agree with Note [Tidying multiple names at once]

Note [Tidying multiple names at once] indicates that if multiple
variables have the same name then we shouldn't prioritise one of them
and instead rename them all to a1, a2, a3... etc

This patch implements that change, some error message changes as
expected.

Closes #20932

1 files changed, 12 insertions, 12 deletions

diff --git a/testsuite/tests/partial-sigs/should_compile/T10403.stderr b/testsuite/tests/partial-sigs/should_compile/T10403.stderr
index e329410514..fd38a126c2 100644
--- a/testsuite/tests/partial-sigs/should_compile/T10403.stderr
+++ b/testsuite/tests/partial-sigs/should_compile/T10403.stderr
@@ -2,23 +2,23 @@
 T10403.hs:16:7: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found extra-constraints wildcard standing for ‘Functor f’
       Where: ‘f’ is a rigid type variable bound by
-               the inferred type of h1 :: Functor f => (a -> a1) -> f a -> H f
+               the inferred type of h1 :: Functor f => (a1 -> a2) -> f a1 -> H f
                at T10403.hs:18:1-41
     • In the type signature: h1 :: _ => _
 
 T10403.hs:16:12: warning: [-Wpartial-type-signatures (in -Wdefault)]
-    • Found type wildcard ‘_’ standing for ‘(a -> a1) -> f a -> H f’
-      Where: ‘a1’, ‘a’, ‘f’ are rigid type variables bound by
-               the inferred type of h1 :: Functor f => (a -> a1) -> f a -> H f
+    • Found type wildcard ‘_’ standing for ‘(a1 -> a2) -> f a1 -> H f’
+      Where: ‘a2’, ‘a1’, ‘f’ are rigid type variables bound by
+               the inferred type of h1 :: Functor f => (a1 -> a2) -> f a1 -> H f
                at T10403.hs:18:1-41
     • In the type signature: h1 :: _ => _
 
 T10403.hs:20:7: warning: [-Wpartial-type-signatures (in -Wdefault)]
     • Found type wildcard ‘_’
-        standing for ‘(a -> a1) -> B t0 a -> H (B t0)’
+        standing for ‘(a1 -> a2) -> B t0 a1 -> H (B t0)’
       Where: ‘t0’ is an ambiguous type variable
-             ‘a1’, ‘a’ are rigid type variables bound by
-               the inferred type of h2 :: (a -> a1) -> B t0 a -> H (B t0)
+             ‘a2’, ‘a1’ are rigid type variables bound by
+               the inferred type of h2 :: (a1 -> a2) -> B t0 a1 -> H (B t0)
                at T10403.hs:23:1-41
     • In the type signature: h2 :: _
 
@@ -26,11 +26,11 @@ T10403.hs:29:8: warning: [-Wdeferred-type-errors (in -Wdefault)]
     • Couldn't match type ‘t0’ with ‘t’
       Expected: H (B t)
         Actual: H (B t0)
-        because type variable ‘t’ would escape its scope
-      This (rigid, skolem) type variable is bound by
-        the type signature for:
-          app2 :: forall t. H (B t)
-        at T10403.hs:28:1-15
+    • because type variable ‘t’ would escape its scope
+    This (rigid, skolem) type variable is bound by
+      the type signature for:
+        app2 :: forall t. H (B t)
+      at T10403.hs:28:1-15
     • In the expression: h2 (H . I) (B ())
       In an equation for ‘app2’: app2 = h2 (H . I) (B ())
     • Relevant bindings include