! unparam .
cmp stdout stdout.golden

-- go.mod --
module testdata.tld/foo
-- stdout.golden --
foo.go:8:28: (FooType).oneUnused - a is unused
-- foo.go --
package foo

// FooType is exported, as otherwise go/ssa gets rid of it.
type FooType int

func (f FooType) allUsed(a FooType) FooType { return f + a }

func (f FooType) oneUnused(a FooType) FooType { return 2 * f }
