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