`bad-pattern`

A `define` or `when` pattern breaks the pattern rules.

compile error, shown by synod check.

The rules are in spec/03 section 3.1. Two inline holes cannot stand next to each other, every hole is typed, block holes come last, and words after the head start lower-case. A head is never directly followed by a comparison operator, and a hole type must name a known type.

Example

Check this program to see the diagnostic.

# package p
define Add [a: number] [b: number]
  result (a plus b)

Diagnostic

p/p.synod:2:24: error[bad-pattern]: holes "[a: number]" and "[b: number]" are adjacent

Fix

Put a word between the two holes.

# package p
define Add [a: number] and [b: number]
  result (a plus b)