Rework diagnostics for wrong number of generic args (fixes#66228 and #71924)
This PR reworks the `wrong number of {} arguments` message, so that it provides more details and contextual hints.
This makes it possible to pass the `Impl` directly to functions, instead
of having to pass each of the many fields one at a time. It also
simplifies matches in many cases.
diag: improve closure/generic parameter mismatch
Fixes#51154.
This PR improves the diagnostic when a type parameter is expected and a closure is found, noting that each closure has a distinct type and therefore could not always match the caller-chosen type of the parameter.
r? @estebank
use if let instead of single match arm expressions
use if let instead of single match arm expressions to compact code and reduce nesting (clippy::single_match)
This commit improves the diagnostic when a type parameter is expected
and a closure is found, noting that each closure has a distinct type and
therefore could not always match the caller-chosen type of the
parameter.
Signed-off-by: David Wood <david@davidtw.co>
