tc141.hs:11:12: error:
• You cannot bind scoped type variable ‘a’
in a pattern binding signature
• In the pattern: p :: a
In the pattern: (p :: a, q :: a)
In a pattern binding: (p :: a, q :: a) = x
tc141.hs:11:31: error:
• Couldn't match expected type ‘a1’ with actual type ‘a’
because type variable ‘a1’ would escape its scope
This (rigid, skolem) type variable is bound by
an expression type signature:
a1
at tc141.hs:11:31-34
• In the expression: q :: a
In the expression: (q :: a, p)
In the expression: let (p :: a, q :: a) = x in (q :: a, p)
• Relevant bindings include
p :: a (bound at tc141.hs:11:12)
q :: a (bound at tc141.hs:11:17)
x :: (a, a) (bound at tc141.hs:11:3)
f :: (a, a) -> (t, a) (bound at tc141.hs:11:1)
tc141.hs:13:13: error:
• You cannot bind scoped type variable ‘a’
in a pattern binding signature
• In the pattern: y :: a
In a pattern binding: y :: a = a
In the expression:
let y :: a = a in
let
v :: a
v = b
in v
tc141.hs:15:18: error:
• Couldn't match expected type ‘a1’ with actual type ‘r1’
because type variable ‘a1’ would escape its scope
This (rigid, skolem) type variable is bound by
the type signature for:
v :: a1
at tc141.hs:14:14-19
• In the expression: b
In an equation for ‘v’: v = b
In the expression:
let
v :: a
v = b
in v
• Relevant bindings include
v :: a1 (bound at tc141.hs:15:14)
b :: r1 (bound at tc141.hs:13:5)
g :: r -> r1 -> forall a. a (bound at tc141.hs:13:1)