Bad error message when enums do not match up

[andreabedini]

Describe the bug

When enum do not match up the error is ... bad?

this expression has type Enum, but Enum was expected

To Reproduce

❯ nickel repl
nickel> match { 'a => 1 } 'b
error: dynamic type error
  ┌─ <repl-input-0>:1:1
  │
1 │ match { 'a => 1 } 'b
  │ ^^^^^^^^^^^^^^^^^^^^
  │ │                 │
  │ │                 evaluated to this
  │ this expression has type Enum, but Enum was expected
  │
  = match expects its argument to be a Enum

Expected behavior

The error is not telling us what the interpreter is actually expecting, mentioning 'a and/or 'b.

Environment

• x86_64 GNU/Linux
• nickel-lang-cli nickel 1.4.0 (rev cargore)

[yannham]

Prophetic comment 🙃

nickel/core/src/eval/operation.rs

Line 355 in 8a1e538

// ? We should have a dedicated error for unmatched pattern