"go/token"
)
+// ----------------------------------------------------------------------------
+// API
+
+// An Interface represents an interface type.
+type Interface struct {
+ obj *TypeName // type name object defining this interface; or nil (for better error messages)
+ methods []*Func // ordered list of explicitly declared methods
+ embeddeds []Type // ordered list of explicitly embedded elements
+ embedPos *[]token.Pos // positions of embedded elements; or nil (for error messages) - use pointer to save space
+ complete bool // indicates that obj, methods, and embeddeds are set and type set can be computed
+
+ tset *TypeSet // type set described by this interface, computed lazily
+}
+
+// typeSet returns the type set for interface t.
+func (t *Interface) typeSet() *TypeSet { return computeTypeSet(nil, token.NoPos, t) }
+
+// is reports whether interface t represents types that all satisfy f.
+func (t *Interface) is(f func(Type, bool) bool) bool {
+ switch t := t.typeSet().types.(type) {
+ case nil, *top:
+ // TODO(gri) should settle on top or nil to represent this case
+ return false // we must have at least one type! (was bug)
+ case *Union:
+ return t.is(func(typ Type, tilde bool) bool { return f(typ, tilde) })
+ default:
+ return f(t, false)
+ }
+}
+
+// emptyInterface represents the empty (completed) interface
+var emptyInterface = Interface{complete: true, tset: &topTypeSet}
+
+// NewInterface returns a new interface for the given methods and embedded types.
+// NewInterface takes ownership of the provided methods and may modify their types
+// by setting missing receivers.
+//
+// Deprecated: Use NewInterfaceType instead which allows arbitrary embedded types.
+func NewInterface(methods []*Func, embeddeds []*Named) *Interface {
+ tnames := make([]Type, len(embeddeds))
+ for i, t := range embeddeds {
+ tnames[i] = t
+ }
+ return NewInterfaceType(methods, tnames)
+}
+
+// NewInterfaceType returns a new interface for the given methods and embedded types.
+// NewInterfaceType takes ownership of the provided methods and may modify their types
+// by setting missing receivers.
+func NewInterfaceType(methods []*Func, embeddeds []Type) *Interface {
+ if len(methods) == 0 && len(embeddeds) == 0 {
+ return &emptyInterface
+ }
+
+ // set method receivers if necessary
+ typ := new(Interface)
+ for _, m := range methods {
+ if sig := m.typ.(*Signature); sig.recv == nil {
+ sig.recv = NewVar(m.pos, m.pkg, "", typ)
+ }
+ }
+
+ // TODO(rfindley): this guard is not present in types2. Remove it?
+ // All embedded types should be interfaces; however, defined types
+ // may not yet be fully resolved. Only verify that non-defined types
+ // are interfaces. This matches the behavior of the code before the
+ // fix for #25301 (issue #25596).
+ for _, t := range embeddeds {
+ if _, ok := t.(*Named); !ok && !IsInterface(t) {
+ panic("embedded type is not an interface")
+ }
+ }
+
+ // sort for API stability
+ sortMethods(methods)
+
+ typ.methods = methods
+ typ.embeddeds = embeddeds
+ typ.complete = true
+
+ return typ
+}
+
+// NumExplicitMethods returns the number of explicitly declared methods of interface t.
+func (t *Interface) NumExplicitMethods() int { return len(t.methods) }
+
+// ExplicitMethod returns the i'th explicitly declared method of interface t for 0 <= i < t.NumExplicitMethods().
+// The methods are ordered by their unique Id.
+func (t *Interface) ExplicitMethod(i int) *Func { return t.methods[i] }
+
+// NumEmbeddeds returns the number of embedded types in interface t.
+func (t *Interface) NumEmbeddeds() int { return len(t.embeddeds) }
+
+// Embedded returns the i'th embedded defined (*Named) type of interface t for 0 <= i < t.NumEmbeddeds().
+// The result is nil if the i'th embedded type is not a defined type.
+//
+// Deprecated: Use EmbeddedType which is not restricted to defined (*Named) types.
+func (t *Interface) Embedded(i int) *Named { tname, _ := t.embeddeds[i].(*Named); return tname }
+
+// EmbeddedType returns the i'th embedded type of interface t for 0 <= i < t.NumEmbeddeds().
+func (t *Interface) EmbeddedType(i int) Type { return t.embeddeds[i] }
+
+// NumMethods returns the total number of methods of interface t.
+func (t *Interface) NumMethods() int { return t.typeSet().NumMethods() }
+
+// Method returns the i'th method of interface t for 0 <= i < t.NumMethods().
+// The methods are ordered by their unique Id.
+func (t *Interface) Method(i int) *Func { return t.typeSet().Method(i) }
+
+// Empty reports whether t is the empty interface.
+func (t *Interface) Empty() bool { return t.typeSet().IsTop() }
+
+// IsComparable reports whether interface t is or embeds the predeclared interface "comparable".
+func (t *Interface) IsComparable() bool { return t.typeSet().IsComparable() }
+
+// IsConstraint reports whether interface t is not just a method set.
+func (t *Interface) IsConstraint() bool { return !t.typeSet().IsMethodSet() }
+
+// isSatisfiedBy reports whether interface t's type list is satisfied by the type typ.
+// If the type list is empty (absent), typ trivially satisfies the interface.
+// TODO(gri) This is not a great name. Eventually, we should have a more comprehensive
+// "implements" predicate.
+func (t *Interface) isSatisfiedBy(typ Type) bool {
+ t.Complete()
+ switch t := t.typeSet().types.(type) {
+ case nil:
+ return true // no type restrictions
+ case *Union:
+ r, _ := t.intersect(typ, false)
+ return r != nil
+ default:
+ return Identical(t, typ)
+ }
+}
+
+// Complete computes the interface's type set. It must be called by users of
+// NewInterfaceType and NewInterface after the interface's embedded types are
+// fully defined and before using the interface type in any way other than to
+// form other types. The interface must not contain duplicate methods or a
+// panic occurs. Complete returns the receiver.
+//
+// Deprecated: Type sets are now computed lazily, on demand; this function
+// is only here for backward-compatibility. It does not have to
+// be called explicitly anymore.
+func (t *Interface) Complete() *Interface {
+ // Some tests are still depending on the state change
+ // (string representation of an Interface not containing an
+ // /* incomplete */ marker) caused by the explicit Complete
+ // call, so we compute the type set eagerly here.
+ t.complete = true
+ t.typeSet()
+ return t
+}
+
+func (t *Interface) Underlying() Type { return t }
+func (t *Interface) String() string { return TypeString(t, nil) }
+
+// ----------------------------------------------------------------------------
+// Implementation
+
func (check *Checker) interfaceType(ityp *Interface, iface *ast.InterfaceType, def *Named) {
var tlist []ast.Expr
var tname *ast.Ident // "type" name of first entry in a type list declaration
// At returns the i'th variable of tuple t.
func (t *Tuple) At(i int) *Var { return t.vars[i] }
-// An Interface represents an interface type.
-type Interface struct {
- obj *TypeName // type name object defining this interface; or nil (for better error messages)
- methods []*Func // ordered list of explicitly declared methods
- embeddeds []Type // ordered list of explicitly embedded elements
- embedPos *[]token.Pos // positions of embedded elements; or nil (for error messages) - use pointer to save space
- complete bool // indicates that obj, methods, and embeddeds are set and type set can be computed
-
- tset *TypeSet // type set described by this interface, computed lazily
-}
-
-// typeSet returns the type set for interface t.
-func (t *Interface) typeSet() *TypeSet { return computeTypeSet(nil, token.NoPos, t) }
-
-// is reports whether interface t represents types that all satisfy f.
-func (t *Interface) is(f func(Type, bool) bool) bool {
- switch t := t.typeSet().types.(type) {
- case nil, *top:
- // TODO(gri) should settle on top or nil to represent this case
- return false // we must have at least one type! (was bug)
- case *Union:
- return t.is(func(typ Type, tilde bool) bool { return f(typ, tilde) })
- default:
- return f(t, false)
- }
-}
-
-// emptyInterface represents the empty (completed) interface
-var emptyInterface = Interface{complete: true, tset: &topTypeSet}
-
-// NewInterface returns a new interface for the given methods and embedded types.
-// NewInterface takes ownership of the provided methods and may modify their types
-// by setting missing receivers.
-//
-// Deprecated: Use NewInterfaceType instead which allows arbitrary embedded types.
-func NewInterface(methods []*Func, embeddeds []*Named) *Interface {
- tnames := make([]Type, len(embeddeds))
- for i, t := range embeddeds {
- tnames[i] = t
- }
- return NewInterfaceType(methods, tnames)
-}
-
-// NewInterfaceType returns a new interface for the given methods and embedded types.
-// NewInterfaceType takes ownership of the provided methods and may modify their types
-// by setting missing receivers.
-func NewInterfaceType(methods []*Func, embeddeds []Type) *Interface {
- if len(methods) == 0 && len(embeddeds) == 0 {
- return &emptyInterface
- }
-
- // set method receivers if necessary
- typ := new(Interface)
- for _, m := range methods {
- if sig := m.typ.(*Signature); sig.recv == nil {
- sig.recv = NewVar(m.pos, m.pkg, "", typ)
- }
- }
-
- // All embedded types should be interfaces; however, defined types
- // may not yet be fully resolved. Only verify that non-defined types
- // are interfaces. This matches the behavior of the code before the
- // fix for #25301 (issue #25596).
- for _, t := range embeddeds {
- if _, ok := t.(*Named); !ok && !IsInterface(t) {
- panic("embedded type is not an interface")
- }
- }
-
- // sort for API stability
- sortMethods(methods)
-
- typ.methods = methods
- typ.embeddeds = embeddeds
- typ.complete = true
-
- return typ
-}
-
-// NumExplicitMethods returns the number of explicitly declared methods of interface t.
-func (t *Interface) NumExplicitMethods() int { return len(t.methods) }
-
-// ExplicitMethod returns the i'th explicitly declared method of interface t for 0 <= i < t.NumExplicitMethods().
-// The methods are ordered by their unique Id.
-func (t *Interface) ExplicitMethod(i int) *Func { return t.methods[i] }
-
-// NumEmbeddeds returns the number of embedded types in interface t.
-func (t *Interface) NumEmbeddeds() int { return len(t.embeddeds) }
-
-// Embedded returns the i'th embedded defined (*Named) type of interface t for 0 <= i < t.NumEmbeddeds().
-// The result is nil if the i'th embedded type is not a defined type.
-//
-// Deprecated: Use EmbeddedType which is not restricted to defined (*Named) types.
-func (t *Interface) Embedded(i int) *Named { tname, _ := t.embeddeds[i].(*Named); return tname }
-
-// EmbeddedType returns the i'th embedded type of interface t for 0 <= i < t.NumEmbeddeds().
-func (t *Interface) EmbeddedType(i int) Type { return t.embeddeds[i] }
-
-// NumMethods returns the total number of methods of interface t.
-func (t *Interface) NumMethods() int { return t.typeSet().NumMethods() }
-
-// Method returns the i'th method of interface t for 0 <= i < t.NumMethods().
-// The methods are ordered by their unique Id.
-func (t *Interface) Method(i int) *Func { return t.typeSet().Method(i) }
-
-// Empty reports whether t is the empty interface.
-func (t *Interface) Empty() bool { return t.typeSet().IsTop() }
-
-// IsComparable reports whether interface t is or embeds the predeclared interface "comparable".
-func (t *Interface) IsComparable() bool { return t.typeSet().IsComparable() }
-
-// IsConstraint reports whether interface t is not just a method set.
-func (t *Interface) IsConstraint() bool { return !t.typeSet().IsMethodSet() }
-
-// isSatisfiedBy reports whether interface t's type list is satisfied by the type typ.
-// If the type list is empty (absent), typ trivially satisfies the interface.
-// TODO(gri) This is not a great name. Eventually, we should have a more comprehensive
-// "implements" predicate.
-func (t *Interface) isSatisfiedBy(typ Type) bool {
- t.Complete()
- switch t := t.typeSet().types.(type) {
- case nil:
- return true // no type restrictions
- case *Union:
- r, _ := t.intersect(typ, false)
- return r != nil
- default:
- return Identical(t, typ)
- }
-}
-
-// Complete computes the interface's type set. It must be called by users of
-// NewInterfaceType and NewInterface after the interface's embedded types are
-// fully defined and before using the interface type in any way other than to
-// form other types. The interface must not contain duplicate methods or a
-// panic occurs. Complete returns the receiver.
-//
-// Deprecated: Type sets are now computed lazily, on demand; this function
-// is only here for backward-compatibility. It does not have to
-// be called explicitly anymore.
-func (t *Interface) Complete() *Interface {
- // Some tests are still depending on the state change
- // (string representation of an Interface not containing an
- // /* incomplete */ marker) caused by the explicit Complete
- // call, so we compute the type set eagerly here.
- t.complete = true
- t.typeSet()
- return t
-}
-
// A Map represents a map type.
type Map struct {
key, elem Type
func (t *Slice) Underlying() Type { return t }
func (t *Pointer) Underlying() Type { return t }
func (t *Tuple) Underlying() Type { return t }
-func (t *Interface) Underlying() Type { return t }
func (t *Map) Underlying() Type { return t }
func (t *Chan) Underlying() Type { return t }
func (t *Named) Underlying() Type { return t.expand().underlying }
func (t *Slice) String() string { return TypeString(t, nil) }
func (t *Pointer) String() string { return TypeString(t, nil) }
func (t *Tuple) String() string { return TypeString(t, nil) }
-func (t *Interface) String() string { return TypeString(t, nil) }
func (t *Map) String() string { return TypeString(t, nil) }
func (t *Chan) String() string { return TypeString(t, nil) }
func (t *Named) String() string { return TypeString(t, nil) }