165 reject unknown label on implicit slot callee

✓ Passing Passing: the compiler rejects this program as expected.

Code

// An explicit `label: value` names a parameter. A callee that declares an
// implicit slot (`if { expr: Expression }`) does not make up for a label that
// names nothing — `cond` is not a parameter of `if`, and saying so is the
// frontend's job.
//
// The bare form `if(true)` is the canonical spelling and the implicit slot
// absorbs it (219 call sites across the suite). What this pins is the other
// side: the slot excuses BARE arguments, never a wrong label.
import std/io

if(cond: true)
  | then |> std/io:print.ln("then branch")
  | else |> std/io:print.ln("else branch")

input.k

Actual compiler output

error[PARSE006]: unknown parameter 'cond' — 'if' has no parameter named 'cond'
  --> tests/regression/200_COMPILER_FEATURES/210_PARSER/210_165_reject_unknown_label_on_implicit_slot_callee/input.k:11:0
    |
 11 | if(cond: true)
    | ^
  hint: remove the argument, or label it with a real parameter (e.g. 'expr:')

Must fail at frontend compile:

Parsing or type-checking must reject the program.

Error output must contain

'if' has no parameter named 'cond'

Flows

flow ~if click a branch to expand · @labels scroll to their anchor

if (cond: true)

Test Configuration

MUST_ERROR

← 164 ast locations are file relative 166 fold prefix drops exit arm capture →