An identifier is bound more than once in a pattern.
Erroneous code example:
match (1, 2) { (x, x) => {} // error: identifier `x` is bound more than once in the // same pattern }
Please verify you didn‘t misspell identifiers’ name. Example:
match (1, 2) { (x, y) => {} // ok! }
Or maybe did you mean to unify? Consider using a guard:
# let (A, B, C) = (1, 2, 3); match (A, B, C) { (x, x2, see) if x == x2 => { /* A and B are equal, do one thing */ } (y, z, see) => { /* A and B unequal; do another thing */ } }