Original bug ID: 7093
Reporter: @sliquister
Assigned to: @garrigue
Status: resolved (set by @garrigue on 2017-03-14T08:19:57Z)
Resolution: not a bug
Priority: normal
Severity: minor
Version: 4.02.3
Target version: undecided
Category: typing
Monitored by: @gasche @diml @hcarty

Bug description

When typing this code:

type a = { a : unit }
type b = a
let f (b : b) = b.typo

the compiler gives this error:

File "a.ml", line 3, characters 18-22:
Error: This expression has type b
The field typo does not belong to type a

There are two confusing things here:

• "This expression has type b" despite the position being the record field
  which is not an expression
• When the type expressions are longer, it's easy to assume the error is the usual "this
  expression has type b but an expression was expected of type a", and then get confused.

Can't the error simply be:

File "a.ml", line 3, characters 18-22:
Error: The field typo does not belong to type a

? The first part doesn't seem useful to me.