| // Copyright 2022 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package ifaceassert |
| |
| import ( |
| "go/types" |
| |
| "golang.org/x/tools/internal/typeparams" |
| ) |
| |
| // isParameterized reports whether typ contains any of the type parameters of tparams. |
| // |
| // NOTE: Adapted from go/types/infer.go. If that is exported in a future release remove this copy. |
| func isParameterized(typ types.Type) bool { |
| w := tpWalker{ |
| seen: make(map[types.Type]bool), |
| } |
| return w.isParameterized(typ) |
| } |
| |
| type tpWalker struct { |
| seen map[types.Type]bool |
| } |
| |
| func (w *tpWalker) isParameterized(typ types.Type) (res bool) { |
| // detect cycles |
| if x, ok := w.seen[typ]; ok { |
| return x |
| } |
| w.seen[typ] = false |
| defer func() { |
| w.seen[typ] = res |
| }() |
| |
| switch t := typ.(type) { |
| case nil, *types.Basic: // TODO(gri) should nil be handled here? |
| break |
| |
| case *types.Array: |
| return w.isParameterized(t.Elem()) |
| |
| case *types.Slice: |
| return w.isParameterized(t.Elem()) |
| |
| case *types.Struct: |
| for i, n := 0, t.NumFields(); i < n; i++ { |
| if w.isParameterized(t.Field(i).Type()) { |
| return true |
| } |
| } |
| |
| case *types.Pointer: |
| return w.isParameterized(t.Elem()) |
| |
| case *types.Tuple: |
| n := t.Len() |
| for i := 0; i < n; i++ { |
| if w.isParameterized(t.At(i).Type()) { |
| return true |
| } |
| } |
| |
| case *types.Signature: |
| // t.tparams may not be nil if we are looking at a signature |
| // of a generic function type (or an interface method) that is |
| // part of the type we're testing. We don't care about these type |
| // parameters. |
| // Similarly, the receiver of a method may declare (rather than |
| // use) type parameters, we don't care about those either. |
| // Thus, we only need to look at the input and result parameters. |
| return w.isParameterized(t.Params()) || w.isParameterized(t.Results()) |
| |
| case *types.Interface: |
| for i, n := 0, t.NumMethods(); i < n; i++ { |
| if w.isParameterized(t.Method(i).Type()) { |
| return true |
| } |
| } |
| terms, err := typeparams.InterfaceTermSet(t) |
| if err != nil { |
| panic(err) |
| } |
| for _, term := range terms { |
| if w.isParameterized(term.Type()) { |
| return true |
| } |
| } |
| |
| case *types.Map: |
| return w.isParameterized(t.Key()) || w.isParameterized(t.Elem()) |
| |
| case *types.Chan: |
| return w.isParameterized(t.Elem()) |
| |
| case *types.Named: |
| list := typeparams.NamedTypeArgs(t) |
| for i, n := 0, list.Len(); i < n; i++ { |
| if w.isParameterized(list.At(i)) { |
| return true |
| } |
| } |
| |
| case *typeparams.TypeParam: |
| return true |
| |
| default: |
| panic(t) // unreachable |
| } |
| |
| return false |
| } |