mirror of https://go.googlesource.com/go
573 lines
18 KiB
Go
573 lines
18 KiB
Go
// Code generated by "go test -run=Generate -write=all"; DO NOT EDIT.
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// Source: ../../cmd/compile/internal/types2/predicates.go
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// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This file implements commonly used type predicates.
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package types
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// isValid reports whether t is a valid type.
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func isValid(t Type) bool { return Unalias(t) != Typ[Invalid] }
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// The isX predicates below report whether t is an X.
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// If t is a type parameter the result is false; i.e.,
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// these predicates don't look inside a type parameter.
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func isBoolean(t Type) bool { return isBasic(t, IsBoolean) }
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func isInteger(t Type) bool { return isBasic(t, IsInteger) }
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func isUnsigned(t Type) bool { return isBasic(t, IsUnsigned) }
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func isFloat(t Type) bool { return isBasic(t, IsFloat) }
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func isComplex(t Type) bool { return isBasic(t, IsComplex) }
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func isNumeric(t Type) bool { return isBasic(t, IsNumeric) }
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func isString(t Type) bool { return isBasic(t, IsString) }
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func isIntegerOrFloat(t Type) bool { return isBasic(t, IsInteger|IsFloat) }
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func isConstType(t Type) bool { return isBasic(t, IsConstType) }
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// isBasic reports whether under(t) is a basic type with the specified info.
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// If t is a type parameter the result is false; i.e.,
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// isBasic does not look inside a type parameter.
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func isBasic(t Type, info BasicInfo) bool {
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u, _ := under(t).(*Basic)
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return u != nil && u.info&info != 0
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}
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// The allX predicates below report whether t is an X.
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// If t is a type parameter the result is true if isX is true
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// for all specified types of the type parameter's type set.
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// allX is an optimized version of isX(coreType(t)) (which
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// is the same as underIs(t, isX)).
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func allBoolean(t Type) bool { return allBasic(t, IsBoolean) }
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func allInteger(t Type) bool { return allBasic(t, IsInteger) }
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func allUnsigned(t Type) bool { return allBasic(t, IsUnsigned) }
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func allNumeric(t Type) bool { return allBasic(t, IsNumeric) }
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func allString(t Type) bool { return allBasic(t, IsString) }
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func allOrdered(t Type) bool { return allBasic(t, IsOrdered) }
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func allNumericOrString(t Type) bool { return allBasic(t, IsNumeric|IsString) }
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// allBasic reports whether under(t) is a basic type with the specified info.
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// If t is a type parameter, the result is true if isBasic(t, info) is true
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// for all specific types of the type parameter's type set.
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// allBasic(t, info) is an optimized version of isBasic(coreType(t), info).
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func allBasic(t Type, info BasicInfo) bool {
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if tpar, _ := Unalias(t).(*TypeParam); tpar != nil {
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return tpar.is(func(t *term) bool { return t != nil && isBasic(t.typ, info) })
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}
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return isBasic(t, info)
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}
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// hasName reports whether t has a name. This includes
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// predeclared types, defined types, and type parameters.
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// hasName may be called with types that are not fully set up.
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func hasName(t Type) bool {
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switch Unalias(t).(type) {
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case *Basic, *Named, *TypeParam:
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return true
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}
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return false
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}
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// isTypeLit reports whether t is a type literal.
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// This includes all non-defined types, but also basic types.
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// isTypeLit may be called with types that are not fully set up.
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func isTypeLit(t Type) bool {
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switch Unalias(t).(type) {
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case *Named, *TypeParam:
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return false
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}
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return true
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}
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// isTyped reports whether t is typed; i.e., not an untyped
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// constant or boolean.
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// Safe to call from types that are not fully set up.
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func isTyped(t Type) bool {
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// Alias and named types cannot denote untyped types
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// so there's no need to call Unalias or under, below.
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b, _ := t.(*Basic)
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return b == nil || b.info&IsUntyped == 0
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}
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// isUntyped(t) is the same as !isTyped(t).
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// Safe to call from types that are not fully set up.
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func isUntyped(t Type) bool {
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return !isTyped(t)
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}
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// isUntypedNumeric reports whether t is an untyped numeric type.
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// Safe to call from types that are not fully set up.
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func isUntypedNumeric(t Type) bool {
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// Alias and named types cannot denote untyped types
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// so there's no need to call Unalias or under, below.
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b, _ := t.(*Basic)
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return b != nil && b.info&IsUntyped != 0 && b.info&IsNumeric != 0
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}
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// IsInterface reports whether t is an interface type.
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func IsInterface(t Type) bool {
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_, ok := under(t).(*Interface)
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return ok
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}
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// isNonTypeParamInterface reports whether t is an interface type but not a type parameter.
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func isNonTypeParamInterface(t Type) bool {
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return !isTypeParam(t) && IsInterface(t)
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}
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// isTypeParam reports whether t is a type parameter.
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func isTypeParam(t Type) bool {
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_, ok := Unalias(t).(*TypeParam)
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return ok
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}
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// hasEmptyTypeset reports whether t is a type parameter with an empty type set.
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// The function does not force the computation of the type set and so is safe to
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// use anywhere, but it may report a false negative if the type set has not been
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// computed yet.
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func hasEmptyTypeset(t Type) bool {
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if tpar, _ := Unalias(t).(*TypeParam); tpar != nil && tpar.bound != nil {
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iface, _ := safeUnderlying(tpar.bound).(*Interface)
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return iface != nil && iface.tset != nil && iface.tset.IsEmpty()
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}
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return false
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}
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// isGeneric reports whether a type is a generic, uninstantiated type
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// (generic signatures are not included).
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// TODO(gri) should we include signatures or assert that they are not present?
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func isGeneric(t Type) bool {
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// A parameterized type is only generic if it doesn't have an instantiation already.
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if alias, _ := t.(*Alias); alias != nil && alias.tparams != nil && alias.targs == nil {
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return true
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}
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named := asNamed(t)
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return named != nil && named.obj != nil && named.inst == nil && named.TypeParams().Len() > 0
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}
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// Comparable reports whether values of type T are comparable.
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func Comparable(T Type) bool {
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return comparable(T, true, nil, nil)
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}
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// If dynamic is set, non-type parameter interfaces are always comparable.
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// If reportf != nil, it may be used to report why T is not comparable.
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func comparable(T Type, dynamic bool, seen map[Type]bool, reportf func(string, ...interface{})) bool {
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if seen[T] {
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return true
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}
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if seen == nil {
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seen = make(map[Type]bool)
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}
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seen[T] = true
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switch t := under(T).(type) {
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case *Basic:
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// assume invalid types to be comparable
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// to avoid follow-up errors
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return t.kind != UntypedNil
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case *Pointer, *Chan:
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return true
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case *Struct:
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for _, f := range t.fields {
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if !comparable(f.typ, dynamic, seen, nil) {
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if reportf != nil {
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reportf("struct containing %s cannot be compared", f.typ)
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}
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return false
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}
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}
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return true
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case *Array:
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if !comparable(t.elem, dynamic, seen, nil) {
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if reportf != nil {
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reportf("%s cannot be compared", t)
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}
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return false
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}
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return true
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case *Interface:
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if dynamic && !isTypeParam(T) || t.typeSet().IsComparable(seen) {
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return true
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}
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if reportf != nil {
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if t.typeSet().IsEmpty() {
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reportf("empty type set")
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} else {
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reportf("incomparable types in type set")
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}
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}
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// fallthrough
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}
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return false
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}
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// hasNil reports whether type t includes the nil value.
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func hasNil(t Type) bool {
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switch u := under(t).(type) {
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case *Basic:
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return u.kind == UnsafePointer
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case *Slice, *Pointer, *Signature, *Map, *Chan:
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return true
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case *Interface:
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return !isTypeParam(t) || u.typeSet().underIs(func(u Type) bool {
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return u != nil && hasNil(u)
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})
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}
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return false
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}
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// samePkg reports whether packages a and b are the same.
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func samePkg(a, b *Package) bool {
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// package is nil for objects in universe scope
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if a == nil || b == nil {
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return a == b
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}
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// a != nil && b != nil
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return a.path == b.path
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}
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// An ifacePair is a node in a stack of interface type pairs compared for identity.
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type ifacePair struct {
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x, y *Interface
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prev *ifacePair
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}
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func (p *ifacePair) identical(q *ifacePair) bool {
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return p.x == q.x && p.y == q.y || p.x == q.y && p.y == q.x
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}
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// A comparer is used to compare types.
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type comparer struct {
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ignoreTags bool // if set, identical ignores struct tags
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ignoreInvalids bool // if set, identical treats an invalid type as identical to any type
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}
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// For changes to this code the corresponding changes should be made to unifier.nify.
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func (c *comparer) identical(x, y Type, p *ifacePair) bool {
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x = Unalias(x)
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y = Unalias(y)
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if x == y {
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return true
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}
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if c.ignoreInvalids && (!isValid(x) || !isValid(y)) {
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return true
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}
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switch x := x.(type) {
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case *Basic:
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// Basic types are singletons except for the rune and byte
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// aliases, thus we cannot solely rely on the x == y check
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// above. See also comment in TypeName.IsAlias.
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if y, ok := y.(*Basic); ok {
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return x.kind == y.kind
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}
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case *Array:
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// Two array types are identical if they have identical element types
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// and the same array length.
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if y, ok := y.(*Array); ok {
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// If one or both array lengths are unknown (< 0) due to some error,
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// assume they are the same to avoid spurious follow-on errors.
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return (x.len < 0 || y.len < 0 || x.len == y.len) && c.identical(x.elem, y.elem, p)
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}
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case *Slice:
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// Two slice types are identical if they have identical element types.
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if y, ok := y.(*Slice); ok {
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return c.identical(x.elem, y.elem, p)
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}
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case *Struct:
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// Two struct types are identical if they have the same sequence of fields,
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// and if corresponding fields have the same names, and identical types,
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// and identical tags. Two embedded fields are considered to have the same
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// name. Lower-case field names from different packages are always different.
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if y, ok := y.(*Struct); ok {
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if x.NumFields() == y.NumFields() {
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for i, f := range x.fields {
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g := y.fields[i]
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if f.embedded != g.embedded ||
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!c.ignoreTags && x.Tag(i) != y.Tag(i) ||
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!f.sameId(g.pkg, g.name, false) ||
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!c.identical(f.typ, g.typ, p) {
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return false
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}
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}
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return true
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}
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}
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case *Pointer:
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// Two pointer types are identical if they have identical base types.
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if y, ok := y.(*Pointer); ok {
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return c.identical(x.base, y.base, p)
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}
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case *Tuple:
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// Two tuples types are identical if they have the same number of elements
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// and corresponding elements have identical types.
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if y, ok := y.(*Tuple); ok {
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if x.Len() == y.Len() {
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if x != nil {
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for i, v := range x.vars {
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w := y.vars[i]
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if !c.identical(v.typ, w.typ, p) {
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return false
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}
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}
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}
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return true
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}
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}
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case *Signature:
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y, _ := y.(*Signature)
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if y == nil {
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return false
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}
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// Two function types are identical if they have the same number of
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// parameters and result values, corresponding parameter and result types
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// are identical, and either both functions are variadic or neither is.
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// Parameter and result names are not required to match, and type
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// parameters are considered identical modulo renaming.
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if x.TypeParams().Len() != y.TypeParams().Len() {
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return false
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}
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// In the case of generic signatures, we will substitute in yparams and
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// yresults.
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yparams := y.params
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yresults := y.results
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if x.TypeParams().Len() > 0 {
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// We must ignore type parameter names when comparing x and y. The
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// easiest way to do this is to substitute x's type parameters for y's.
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xtparams := x.TypeParams().list()
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ytparams := y.TypeParams().list()
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var targs []Type
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for i := range xtparams {
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targs = append(targs, x.TypeParams().At(i))
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}
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smap := makeSubstMap(ytparams, targs)
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var check *Checker // ok to call subst on a nil *Checker
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ctxt := NewContext() // need a non-nil Context for the substitution below
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// Constraints must be pair-wise identical, after substitution.
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for i, xtparam := range xtparams {
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ybound := check.subst(nopos, ytparams[i].bound, smap, nil, ctxt)
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if !c.identical(xtparam.bound, ybound, p) {
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return false
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}
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}
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yparams = check.subst(nopos, y.params, smap, nil, ctxt).(*Tuple)
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yresults = check.subst(nopos, y.results, smap, nil, ctxt).(*Tuple)
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}
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return x.variadic == y.variadic &&
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c.identical(x.params, yparams, p) &&
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c.identical(x.results, yresults, p)
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case *Union:
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if y, _ := y.(*Union); y != nil {
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// TODO(rfindley): can this be reached during type checking? If so,
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// consider passing a type set map.
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unionSets := make(map[*Union]*_TypeSet)
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xset := computeUnionTypeSet(nil, unionSets, nopos, x)
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yset := computeUnionTypeSet(nil, unionSets, nopos, y)
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return xset.terms.equal(yset.terms)
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}
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case *Interface:
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// Two interface types are identical if they describe the same type sets.
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// With the existing implementation restriction, this simplifies to:
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//
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// Two interface types are identical if they have the same set of methods with
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// the same names and identical function types, and if any type restrictions
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// are the same. Lower-case method names from different packages are always
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// different. The order of the methods is irrelevant.
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if y, ok := y.(*Interface); ok {
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xset := x.typeSet()
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yset := y.typeSet()
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if xset.comparable != yset.comparable {
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return false
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}
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if !xset.terms.equal(yset.terms) {
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return false
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}
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a := xset.methods
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b := yset.methods
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if len(a) == len(b) {
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// Interface types are the only types where cycles can occur
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// that are not "terminated" via named types; and such cycles
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// can only be created via method parameter types that are
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// anonymous interfaces (directly or indirectly) embedding
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// the current interface. Example:
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//
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// type T interface {
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// m() interface{T}
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// }
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//
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// If two such (differently named) interfaces are compared,
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// endless recursion occurs if the cycle is not detected.
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//
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// If x and y were compared before, they must be equal
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// (if they were not, the recursion would have stopped);
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// search the ifacePair stack for the same pair.
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//
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// This is a quadratic algorithm, but in practice these stacks
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// are extremely short (bounded by the nesting depth of interface
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// type declarations that recur via parameter types, an extremely
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// rare occurrence). An alternative implementation might use a
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// "visited" map, but that is probably less efficient overall.
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q := &ifacePair{x, y, p}
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for p != nil {
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if p.identical(q) {
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return true // same pair was compared before
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}
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p = p.prev
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}
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if debug {
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assertSortedMethods(a)
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assertSortedMethods(b)
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}
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for i, f := range a {
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g := b[i]
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if f.Id() != g.Id() || !c.identical(f.typ, g.typ, q) {
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return false
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}
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}
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return true
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}
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}
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case *Map:
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// Two map types are identical if they have identical key and value types.
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if y, ok := y.(*Map); ok {
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return c.identical(x.key, y.key, p) && c.identical(x.elem, y.elem, p)
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}
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case *Chan:
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// Two channel types are identical if they have identical value types
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// and the same direction.
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if y, ok := y.(*Chan); ok {
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return x.dir == y.dir && c.identical(x.elem, y.elem, p)
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}
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case *Named:
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// Two named types are identical if their type names originate
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// in the same type declaration; if they are instantiated they
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// must have identical type argument lists.
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if y := asNamed(y); y != nil {
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// check type arguments before origins to match unifier
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// (for correct source code we need to do all checks so
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// order doesn't matter)
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xargs := x.TypeArgs().list()
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yargs := y.TypeArgs().list()
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if len(xargs) != len(yargs) {
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return false
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}
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for i, xarg := range xargs {
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if !Identical(xarg, yargs[i]) {
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return false
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}
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}
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return identicalOrigin(x, y)
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}
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case *TypeParam:
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// nothing to do (x and y being equal is caught in the very beginning of this function)
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case nil:
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// avoid a crash in case of nil type
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default:
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panic("unreachable")
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}
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return false
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}
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|
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// identicalOrigin reports whether x and y originated in the same declaration.
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func identicalOrigin(x, y *Named) bool {
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|
// TODO(gri) is this correct?
|
|
return x.Origin().obj == y.Origin().obj
|
|
}
|
|
|
|
// identicalInstance reports if two type instantiations are identical.
|
|
// Instantiations are identical if their origin and type arguments are
|
|
// identical.
|
|
func identicalInstance(xorig Type, xargs []Type, yorig Type, yargs []Type) bool {
|
|
if len(xargs) != len(yargs) {
|
|
return false
|
|
}
|
|
|
|
for i, xa := range xargs {
|
|
if !Identical(xa, yargs[i]) {
|
|
return false
|
|
}
|
|
}
|
|
|
|
return Identical(xorig, yorig)
|
|
}
|
|
|
|
// Default returns the default "typed" type for an "untyped" type;
|
|
// it returns the incoming type for all other types. The default type
|
|
// for untyped nil is untyped nil.
|
|
func Default(t Type) Type {
|
|
// Alias and named types cannot denote untyped types
|
|
// so there's no need to call Unalias or under, below.
|
|
if t, _ := t.(*Basic); t != nil {
|
|
switch t.kind {
|
|
case UntypedBool:
|
|
return Typ[Bool]
|
|
case UntypedInt:
|
|
return Typ[Int]
|
|
case UntypedRune:
|
|
return universeRune // use 'rune' name
|
|
case UntypedFloat:
|
|
return Typ[Float64]
|
|
case UntypedComplex:
|
|
return Typ[Complex128]
|
|
case UntypedString:
|
|
return Typ[String]
|
|
}
|
|
}
|
|
return t
|
|
}
|
|
|
|
// maxType returns the "largest" type that encompasses both x and y.
|
|
// If x and y are different untyped numeric types, the result is the type of x or y
|
|
// that appears later in this list: integer, rune, floating-point, complex.
|
|
// Otherwise, if x != y, the result is nil.
|
|
func maxType(x, y Type) Type {
|
|
// We only care about untyped types (for now), so == is good enough.
|
|
// TODO(gri) investigate generalizing this function to simplify code elsewhere
|
|
if x == y {
|
|
return x
|
|
}
|
|
if isUntypedNumeric(x) && isUntypedNumeric(y) {
|
|
// untyped types are basic types
|
|
if x.(*Basic).kind > y.(*Basic).kind {
|
|
return x
|
|
}
|
|
return y
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// clone makes a "flat copy" of *p and returns a pointer to the copy.
|
|
func clone[P *T, T any](p P) P {
|
|
c := *p
|
|
return &c
|
|
}
|