pub fn builtin_generic_param_count(name: &str) -> Option<usize>Expand description
How many type parameters a BUILT-IN generic takes — the one table the whole compiler asks.
★ IT LIVES HERE BECAUSE IT WAS ANSWERED IN THREE PLACES AND THEY DISAGREED. The type-expression
parser knew Result takes two; the two record-FIELD parsers knew only that Map does, so a
field typed Result of Int and E read as a ONE-parameter Result and silently dropped its error
type — and with it the whole record, since a field whose type will not resolve takes its struct
out of the layout tables. Pair/Triple fields went the same way. A field declaring a type the
language accepts everywhere else must mean the same thing here.
A registry lookup takes precedence for a USER generic; this answers for the built-ins only.