api/vendor/honnef.co/go/tools/unused/implements.go

80 lines
1.8 KiB
Go

package unused
import "go/types"
// lookupMethod returns the index of and method with matching package and name, or (-1, nil).
func lookupMethod(T *types.Interface, pkg *types.Package, name string) (int, *types.Func) {
if name != "_" {
for i := 0; i < T.NumMethods(); i++ {
m := T.Method(i)
if sameId(m, pkg, name) {
return i, m
}
}
}
return -1, nil
}
func sameId(obj types.Object, pkg *types.Package, name string) bool {
// spec:
// "Two identifiers are different if they are spelled differently,
// or if they appear in different packages and are not exported.
// Otherwise, they are the same."
if name != obj.Name() {
return false
}
// obj.Name == name
if obj.Exported() {
return true
}
// not exported, so packages must be the same (pkg == nil for
// fields in Universe scope; this can only happen for types
// introduced via Eval)
if pkg == nil || obj.Pkg() == nil {
return pkg == obj.Pkg()
}
// pkg != nil && obj.pkg != nil
return pkg.Path() == obj.Pkg().Path()
}
func (c *Checker) implements(V types.Type, T *types.Interface) bool {
// fast path for common case
if T.Empty() {
return true
}
if ityp, _ := V.Underlying().(*types.Interface); ityp != nil {
for i := 0; i < T.NumMethods(); i++ {
m := T.Method(i)
_, obj := lookupMethod(ityp, m.Pkg(), m.Name())
switch {
case obj == nil:
return false
case !types.Identical(obj.Type(), m.Type()):
return false
}
}
return true
}
// A concrete type implements T if it implements all methods of T.
ms := c.msCache.MethodSet(V)
for i := 0; i < T.NumMethods(); i++ {
m := T.Method(i)
sel := ms.Lookup(m.Pkg(), m.Name())
if sel == nil {
return false
}
f, _ := sel.Obj().(*types.Func)
if f == nil {
return false
}
if !types.Identical(f.Type(), m.Type()) {
return false
}
}
return true
}