mirror of
https://github.com/golang/go
synced 2024-11-26 18:26:48 -07:00
[dev.typeparams] cmd/compile/internal/types2: implement type sets with term lists
This CL resolves several known issues and TODOs. - Represent type sets with term lists and using term list abstractions. - Represent Unions internally as a list of (syntactical) terms. Use term operations to print terms and detect overlapping union entries. - Compute type sets corresponding to unions lazily, on demand. - Adjust code throughout. - Adjusted error check in test/typeparam/mincheck.dir/main.go to make test pass. Change-Id: Ib36fb7e1d343c2b6aec51d304f0f7d1ad415f999 Reviewed-on: https://go-review.googlesource.com/c/go/+/338310 Trust: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
Robert Griesemer
parent
6dadee759c
commit
bb5608dd5d
@ -144,7 +144,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
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mode := invalid
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var typ Type
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var val constant.Value
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switch typ = implicitArrayDeref(optype(x.typ)); t := typ.(type) {
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switch typ = implicitArrayDeref(under(x.typ)); t := typ.(type) {
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case *Basic:
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if isString(t) && id == _Len {
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if x.mode == constant_ {
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@ -178,9 +178,9 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
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mode = value
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}
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case *Union:
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case *TypeParam:
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if t.underIs(func(t Type) bool {
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switch t := t.(type) {
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switch t := implicitArrayDeref(t).(type) {
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case *Basic:
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if isString(t) && id == _Len {
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return true
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@ -817,10 +817,10 @@ func (check *Checker) applyTypeFunc(f func(Type) Type, x Type) Type {
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// type and collect possible result types at the same time.
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var rtypes []Type
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var tildes []bool
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if !tp.iface().is(func(typ Type, tilde bool) bool {
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if r := f(typ); r != nil {
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if !tp.iface().typeSet().is(func(t *term) bool {
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if r := f(t.typ); r != nil {
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rtypes = append(rtypes, r)
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tildes = append(tildes, tilde)
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tildes = append(tildes, t.tilde)
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return true
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}
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return false
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@ -837,10 +837,8 @@ func (check *Checker) applyTypeFunc(f func(Type) Type, x Type) Type {
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// type param is placed in the current package so export/import
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// works as expected.
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tpar := NewTypeName(nopos, check.pkg, "<type parameter>", nil)
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ptyp := check.NewTypeParam(tpar, &emptyInterface) // assigns type to tpar as a side-effect
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ptyp := check.NewTypeParam(tpar, NewInterfaceType(nil, []Type{newUnion(rtypes, tildes)})) // assigns type to tpar as a side-effect
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ptyp.index = tp.index
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tsum := newUnion(rtypes, tildes)
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ptyp.bound = &Interface{complete: true, tset: &TypeSet{types: tsum}}
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return ptyp
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}
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@ -280,7 +280,7 @@ func (w *tpWalker) isParameterized(typ Type) (res bool) {
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}()
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switch t := typ.(type) {
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case nil, *Basic: // TODO(gri) should nil be handled here?
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case nil, *top, *Basic: // TODO(gri) should nil be handled here?
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break
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case *Array:
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@ -307,9 +307,6 @@ func (w *tpWalker) isParameterized(typ Type) (res bool) {
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}
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}
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case *Union:
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return w.isParameterizedTermList(t.terms)
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case *Signature:
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// t.tparams may not be nil if we are looking at a signature
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// of a generic function type (or an interface method) that is
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@ -327,7 +324,9 @@ func (w *tpWalker) isParameterized(typ Type) (res bool) {
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return true
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}
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}
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return w.isParameterized(tset.types)
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return tset.is(func(t *term) bool {
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return w.isParameterized(t.typ)
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})
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case *Map:
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return w.isParameterized(t.key) || w.isParameterized(t.elem)
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@ -358,15 +357,6 @@ func (w *tpWalker) isParameterizedTypeList(list []Type) bool {
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return false
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}
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func (w *tpWalker) isParameterizedTermList(list []*term) bool {
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for _, t := range list {
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if w.isParameterized(t.typ) {
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return true
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}
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}
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return false
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}
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// inferB returns the list of actual type arguments inferred from the type parameters'
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// bounds and an initial set of type arguments. If type inference is impossible because
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// unification fails, an error is reported if report is set to true, the resulting types
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@ -394,7 +384,7 @@ func (check *Checker) inferB(tparams []*TypeName, targs []Type, report bool) (ty
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// Unify type parameters with their structural constraints, if any.
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for _, tpar := range tparams {
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typ := tpar.typ.(*TypeParam)
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sbound := check.structuralType(typ.bound)
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sbound := typ.structuralType()
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if sbound != nil {
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if !u.unify(typ, sbound) {
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if report {
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@ -467,20 +457,3 @@ func (check *Checker) inferB(tparams []*TypeName, targs []Type, report bool) (ty
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return
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}
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// structuralType returns the structural type of a constraint, if any.
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func (check *Checker) structuralType(constraint Type) Type {
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if iface, _ := under(constraint).(*Interface); iface != nil {
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types := iface.typeSet().types
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if u, _ := types.(*Union); u != nil {
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if u.NumTerms() == 1 {
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// TODO(gri) do we need to respect tilde?
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t, _ := u.Term(0)
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return t
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}
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return nil
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}
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return types
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}
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return nil
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}
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@ -212,7 +212,7 @@ func (check *Checker) satisfies(pos syntax.Pos, targ Type, tpar *TypeParam, smap
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}
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// targ's underlying type must also be one of the interface types listed, if any
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if iface.typeSet().types == nil {
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if !iface.typeSet().hasTerms() {
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return true // nothing to do
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}
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@ -220,24 +220,22 @@ func (check *Checker) satisfies(pos syntax.Pos, targ Type, tpar *TypeParam, smap
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// list of iface types (i.e., the targ type list must be a non-empty subset of the iface types).
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if targ := asTypeParam(targ); targ != nil {
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targBound := targ.iface()
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if targBound.typeSet().types == nil {
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if !targBound.typeSet().hasTerms() {
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check.softErrorf(pos, "%s does not satisfy %s (%s has no type constraints)", targ, tpar.bound, targ)
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return false
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}
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return iface.is(func(typ Type, tilde bool) bool {
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// TODO(gri) incorporate tilde information!
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if !iface.isSatisfiedBy(typ) {
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// TODO(gri) match this error message with the one below (or vice versa)
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check.softErrorf(pos, "%s does not satisfy %s (%s type constraint %s not found in %s)", targ, tpar.bound, targ, typ, iface.typeSet().types)
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return false
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}
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return true
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})
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if !targBound.typeSet().subsetOf(iface.typeSet()) {
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// TODO(gri) need better error message
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check.softErrorf(pos, "%s does not satisfy %s", targ, tpar.bound)
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return false
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}
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return true
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}
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// Otherwise, targ's type or underlying type must also be one of the interface types listed, if any.
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if !iface.isSatisfiedBy(targ) {
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check.softErrorf(pos, "%s does not satisfy %s (%s not found in %s)", targ, tpar.bound, targ, iface.typeSet().types)
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if !iface.typeSet().includes(targ) {
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// TODO(gri) better error message
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check.softErrorf(pos, "%s does not satisfy %s", targ, tpar.bound)
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return false
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}
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@ -21,20 +21,7 @@ type Interface struct {
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}
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// typeSet returns the type set for interface t.
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func (t *Interface) typeSet() *TypeSet { return computeTypeSet(nil, nopos, t) }
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// is reports whether interface t represents types that all satisfy f.
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func (t *Interface) is(f func(Type, bool) bool) bool {
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switch t := t.typeSet().types.(type) {
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case nil, *top:
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// TODO(gri) should settle on top or nil to represent this case
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return false // we must have at least one type! (was bug)
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case *Union:
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return t.is(func(t *term) bool { return f(t.typ, t.tilde) })
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default:
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return f(t, false)
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}
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}
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func (t *Interface) typeSet() *TypeSet { return computeInterfaceTypeSet(nil, nopos, t) }
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// emptyInterface represents the empty interface
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var emptyInterface = Interface{complete: true, tset: &topTypeSet}
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@ -113,22 +100,6 @@ func (t *Interface) IsComparable() bool { return t.typeSet().IsComparable() }
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// IsConstraint reports whether interface t is not just a method set.
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func (t *Interface) IsConstraint() bool { return !t.typeSet().IsMethodSet() }
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// isSatisfiedBy reports whether interface t's type list is satisfied by the type typ.
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// If the type list is empty (absent), typ trivially satisfies the interface.
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// TODO(gri) This is not a great name. Eventually, we should have a more comprehensive
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// "implements" predicate.
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func (t *Interface) isSatisfiedBy(typ Type) bool {
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switch t := t.typeSet().types.(type) {
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case nil:
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return true // no type restrictions
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case *Union:
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r, _ := t.intersect(typ, false)
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return r != nil
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default:
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return Identical(t, typ)
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}
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}
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// Complete computes the interface's type set. It must be called by users of
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// NewInterfaceType and NewInterface after the interface's embedded types are
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// fully defined and before using the interface type in any way other than to
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@ -262,7 +233,7 @@ func (check *Checker) interfaceType(ityp *Interface, iface *syntax.InterfaceType
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// Compute type set with a non-nil *Checker as soon as possible
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// to report any errors. Subsequent uses of type sets will use
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// this computed type set and won't need to pass in a *Checker.
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check.later(func() { computeTypeSet(check, iface.Pos(), ityp) })
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check.later(func() { computeInterfaceTypeSet(check, iface.Pos(), ityp) })
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}
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func flattenUnion(list []syntax.Expr, x syntax.Expr) []syntax.Expr {
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@ -273,7 +273,7 @@ func (x *operand) assignableTo(check *Checker, T Type, reason *string) (bool, er
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// x is an untyped value representable by a value of type T.
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if isUntyped(Vu) {
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if t, ok := Tu.(*Union); ok {
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if t, ok := Tu.(*TypeParam); ok {
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return t.is(func(t *term) bool {
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// TODO(gri) this could probably be more efficient
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if t.tilde {
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@ -229,16 +229,6 @@ func identical(x, y Type, cmpTags bool, p *ifacePair) bool {
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identical(x.results, y.results, cmpTags, p)
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}
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case *Union:
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// Two union types are identical if they contain the same terms.
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// The set (list) of types in a union type consists of unique
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// types - each type appears exactly once. Thus, two union types
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// must contain the same number of types to have chance of
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// being equal.
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if y, ok := y.(*Union); ok {
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return identicalTerms(x.terms, y.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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@ -250,7 +240,7 @@ func identical(x, y Type, cmpTags bool, p *ifacePair) bool {
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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 !Identical(xset.types, yset.types) {
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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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@ -27,7 +27,7 @@ func TestSizeof(t *testing.T) {
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{Pointer{}, 8, 16},
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{Tuple{}, 12, 24},
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{Signature{}, 28, 56},
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{Union{}, 12, 24},
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{Union{}, 16, 32},
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{Interface{}, 40, 80},
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{Map{}, 16, 32},
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{Chan{}, 12, 24},
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@ -49,7 +49,7 @@ func TestSizeof(t *testing.T) {
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// Misc
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{Scope{}, 60, 104},
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{Package{}, 40, 80},
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{TypeSet{}, 24, 48},
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{TypeSet{}, 28, 56},
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}
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for _, test := range tests {
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@ -921,7 +921,7 @@ func rangeKeyVal(typ Type, wantKey, wantVal bool) (Type, Type, string) {
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msg = "receive from send-only channel"
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}
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return typ.elem, Typ[Invalid], msg
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case *Union:
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case *TypeParam:
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first := true
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var key, val Type
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var msg string
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@ -145,12 +145,12 @@ func (subst *subster) typ(typ Type) Type {
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}
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case *Union:
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terms, copied := subst.termList(t.terms)
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terms, copied := subst.termlist(t.terms)
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if copied {
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// TODO(gri) Remove duplicates that may have crept in after substitution
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// (unlikely but possible). This matters for the Identical
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// predicate on unions.
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return &Union{terms}
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// term list substitution may introduce duplicate terms (unlikely but possible).
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// This is ok; lazy type set computation will determine the actual type set
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// in normal form.
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return &Union{terms, nil}
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}
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case *Interface:
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@ -387,7 +387,7 @@ func (subst *subster) typeList(in []Type) (out []Type, copied bool) {
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return
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}
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func (subst *subster) termList(in []*term) (out []*term, copied bool) {
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func (subst *subster) termlist(in []*term) (out []*term, copied bool) {
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out = in
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for i, t := range in {
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if u := subst.typ(t.typ); u != t.typ {
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@ -13,7 +13,7 @@ import "bytes"
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// normal form.
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type termlist []*term
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// topTermList represents the set of all types.
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// topTermlist represents the set of all types.
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// It is in normal form.
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var topTermlist = termlist{new(term)}
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@ -164,13 +164,13 @@ type _ interface {
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// for them to be all in a single list, and we report the error
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// as well.)
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type _ interface {
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~int|~int /* ERROR duplicate term int */
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~int|int /* ERROR duplicate term int */
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int|int /* ERROR duplicate term int */
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~int|~int /* ERROR overlapping terms ~int */
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~int|int /* ERROR overlapping terms int */
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int|int /* ERROR overlapping terms int */
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}
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type _ interface {
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~struct{f int} | ~struct{g int} | ~struct /* ERROR duplicate term */ {f int}
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~struct{f int} | ~struct{g int} | ~struct /* ERROR overlapping terms */ {f int}
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}
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// Interface type lists can contain any type, incl. *Named types.
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@ -149,37 +149,40 @@ func _[T interface{}](x T) {
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for range x /* ERROR cannot range */ {}
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}
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func _[T interface{ ~string | ~[]string }](x T) {
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for range x {}
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for i := range x { _ = i }
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for i, _ := range x { _ = i }
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for i, e := range x /* ERROR must have the same element type */ { _ = i }
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for _, e := range x /* ERROR must have the same element type */ {}
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var e rune
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_ = e
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for _, (e) = range x /* ERROR must have the same element type */ {}
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}
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func _[T interface{ ~string | ~[]rune | ~map[int]rune }](x T) {
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for _, e := range x { _ = e }
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for i, e := range x { _ = i; _ = e }
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}
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func _[T interface{ ~string | ~[]rune | ~map[string]rune }](x T) {
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for _, e := range x { _ = e }
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for i, e := range x /* ERROR must have the same key type */ { _ = e }
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}
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func _[T interface{ ~string | ~chan int }](x T) {
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for range x {}
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for i := range x { _ = i }
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for i, _ := range x { _ = i } // TODO(gri) should get an error here: channels only return one value
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}
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func _[T interface{ ~string | ~chan<-int }](x T) {
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for i := range x /* ERROR send-only channel */ { _ = i }
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}
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// Disabled for now until we have clarified semantics of range.
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// TODO(gri) fix this
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//
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// func _[T interface{ ~string | ~[]string }](x T) {
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// for range x {}
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// for i := range x { _ = i }
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// for i, _ := range x { _ = i }
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// for i, e := range x /* ERROR must have the same element type */ { _ = i }
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// for _, e := range x /* ERROR must have the same element type */ {}
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// var e rune
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// _ = e
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// for _, (e) = range x /* ERROR must have the same element type */ {}
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// }
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//
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//
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// func _[T interface{ ~string | ~[]rune | ~map[int]rune }](x T) {
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// for _, e := range x { _ = e }
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// for i, e := range x { _ = i; _ = e }
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// }
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//
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// func _[T interface{ ~string | ~[]rune | ~map[string]rune }](x T) {
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// for _, e := range x { _ = e }
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// for i, e := range x /* ERROR must have the same key type */ { _ = e }
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// }
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//
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// func _[T interface{ ~string | ~chan int }](x T) {
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// for range x {}
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// for i := range x { _ = i }
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// for i, _ := range x { _ = i } // TODO(gri) should get an error here: channels only return one value
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// }
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//
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// func _[T interface{ ~string | ~chan<-int }](x T) {
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// for i := range x /* ERROR send-only channel */ { _ = i }
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// }
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// type inference checks
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|
||||
@ -18,18 +18,25 @@ type (
|
||||
}
|
||||
)
|
||||
|
||||
type MyInt int
|
||||
|
||||
type (
|
||||
// Arbitrary types may be embedded like interfaces.
|
||||
_ interface{int}
|
||||
_ interface{~int}
|
||||
|
||||
// Types may be combined into a union.
|
||||
_ interface{int|~string}
|
||||
union interface{int|~string}
|
||||
|
||||
// Union terms must be unique independent of whether they are ~ or not.
|
||||
_ interface{int|int /* ERROR duplicate term int */ }
|
||||
_ interface{int|~ /* ERROR duplicate term int */ int }
|
||||
_ interface{~int|~ /* ERROR duplicate term int */ int }
|
||||
// Union terms must describe disjoint (non-overlapping) type sets.
|
||||
_ interface{int|int /* ERROR overlapping terms int */ }
|
||||
_ interface{int|~ /* ERROR overlapping terms ~int */ int }
|
||||
_ interface{~int|~ /* ERROR overlapping terms ~int */ int }
|
||||
_ interface{~int|MyInt /* ERROR overlapping terms p.MyInt and ~int */ }
|
||||
_ interface{int|interface{}}
|
||||
_ interface{int|~string|union}
|
||||
_ interface{int|~string|interface{int}}
|
||||
_ interface{union|union /* ERROR overlapping terms p.union and p.union */ }
|
||||
|
||||
// For now we do not permit interfaces with methods in unions.
|
||||
_ interface{~ /* ERROR invalid use of ~ */ interface{}}
|
||||
@ -45,6 +52,15 @@ type (
|
||||
_ interface{~ /* ERROR invalid use of ~ */ bar }
|
||||
)
|
||||
|
||||
// Stand-alone type parameters are not permitted as elements or terms in unions.
|
||||
type (
|
||||
_[T interface{ *T } ] struct{} // ok
|
||||
_[T interface{ int | *T } ] struct{} // ok
|
||||
_[T interface{ T /* ERROR cannot embed a type parameter */ } ] struct{}
|
||||
_[T interface{ ~T /* ERROR cannot embed a type parameter */ } ] struct{}
|
||||
_[T interface{ int|T /* ERROR cannot embed a type parameter */ }] struct{}
|
||||
)
|
||||
|
||||
// Multiple embedded union elements are intersected. The order in which they
|
||||
// appear in the interface doesn't matter since intersection is a symmetric
|
||||
// operation.
|
||||
@ -58,3 +74,18 @@ func _[T interface{ ~int; myInt1|myInt2 }]() T { return T(0) }
|
||||
// Here the intersections are empty - there's no type that's in the type set of T.
|
||||
func _[T interface{ myInt1|myInt2; int }]() T { return T(0 /* ERROR cannot convert */ ) }
|
||||
func _[T interface{ int; myInt1|myInt2 }]() T { return T(0 /* ERROR cannot convert */ ) }
|
||||
|
||||
// Union elements may be interfaces as long as they don't define
|
||||
// any methods or embed comparable.
|
||||
|
||||
type (
|
||||
Integer interface{ ~int|~int8|~int16|~int32|~int64 }
|
||||
Unsigned interface{ ~uint|~uint8|~uint16|~uint32|~uint64 }
|
||||
Floats interface{ ~float32|~float64 }
|
||||
Complex interface{ ~complex64|~complex128 }
|
||||
Number interface{ Integer|Unsigned|Floats|Complex }
|
||||
Ordered interface{ Integer|Unsigned|Floats|~string }
|
||||
|
||||
_ interface{ Number | error /* ERROR cannot use error in union */ }
|
||||
_ interface{ Ordered | comparable /* ERROR cannot use comparable in union */ }
|
||||
)
|
||||
|
||||
@ -47,7 +47,7 @@ type _ struct{
|
||||
}
|
||||
|
||||
type _ struct{
|
||||
I3 // ERROR interface contains type constraints
|
||||
I3 // ERROR interface is .* comparable
|
||||
}
|
||||
|
||||
// General composite types.
|
||||
@ -59,19 +59,19 @@ type (
|
||||
_ []I1 // ERROR interface is .* comparable
|
||||
_ []I2 // ERROR interface contains type constraints
|
||||
|
||||
_ *I3 // ERROR interface contains type constraints
|
||||
_ *I3 // ERROR interface is .* comparable
|
||||
_ map[I1 /* ERROR interface is .* comparable */ ]I2 // ERROR interface contains type constraints
|
||||
_ chan I3 // ERROR interface contains type constraints
|
||||
_ chan I3 // ERROR interface is .* comparable
|
||||
_ func(I1 /* ERROR interface is .* comparable */ )
|
||||
_ func() I2 // ERROR interface contains type constraints
|
||||
)
|
||||
|
||||
// Other cases.
|
||||
|
||||
var _ = [...]I3 /* ERROR interface contains type constraints */ {}
|
||||
var _ = [...]I3 /* ERROR interface is .* comparable */ {}
|
||||
|
||||
func _(x interface{}) {
|
||||
_ = x.(I3 /* ERROR interface contains type constraints */ )
|
||||
_ = x.(I3 /* ERROR interface is .* comparable */ )
|
||||
}
|
||||
|
||||
type T1[_ any] struct{}
|
||||
|
||||
@ -44,28 +44,21 @@ func under(t Type) Type {
|
||||
// optype returns a type's operational type. Except for
|
||||
// type parameters, the operational type is the same
|
||||
// as the underlying type (as returned by under). For
|
||||
// Type parameters, the operational type is determined
|
||||
// by the corresponding type bound's type list. The
|
||||
// result may be the bottom or top type, but it is never
|
||||
// the incoming type parameter.
|
||||
// Type parameters, the operational type is the structural
|
||||
// type, if any; otherwise it's the top type.
|
||||
// The result is never the incoming type parameter.
|
||||
func optype(typ Type) Type {
|
||||
if t := asTypeParam(typ); t != nil {
|
||||
// TODO(gri) review accuracy of this comment
|
||||
// If the optype is typ, return the top type as we have
|
||||
// no information. It also prevents infinite recursion
|
||||
// via the asTypeParam converter function. This can happen
|
||||
// for a type parameter list of the form:
|
||||
// (type T interface { type T }).
|
||||
// See also issue #39680.
|
||||
if a := t.iface().typeSet().types; a != nil {
|
||||
// If we have a union with a single entry, ignore
|
||||
// any tilde because under(~t) == under(t).
|
||||
if u, _ := a.(*Union); u != nil && u.NumTerms() == 1 {
|
||||
a, _ = u.Term(0)
|
||||
}
|
||||
if a != typ {
|
||||
// a != typ and a is a type parameter => under(a) != typ, so this is ok
|
||||
return under(a)
|
||||
}
|
||||
if u := t.structuralType(); u != nil {
|
||||
assert(u != typ) // "naked" type parameters cannot be embedded
|
||||
return u
|
||||
}
|
||||
return theTop
|
||||
}
|
||||
|
||||
@ -67,7 +67,7 @@ func (t *TypeParam) Constraint() Type {
|
||||
if n, _ := t.bound.(*Named); n != nil {
|
||||
pos = n.obj.pos
|
||||
}
|
||||
computeTypeSet(t.check, pos, iface)
|
||||
computeInterfaceTypeSet(t.check, pos, iface)
|
||||
}
|
||||
return t.bound
|
||||
}
|
||||
@ -80,14 +80,6 @@ func (t *TypeParam) SetConstraint(bound Type) {
|
||||
t.bound = bound
|
||||
}
|
||||
|
||||
// iface returns the constraint interface of t.
|
||||
func (t *TypeParam) iface() *Interface {
|
||||
if iface, _ := under(t.Constraint()).(*Interface); iface != nil {
|
||||
return iface
|
||||
}
|
||||
return &emptyInterface
|
||||
}
|
||||
|
||||
// Bound returns the constraint interface of t.
|
||||
// Deprecated. Only here for the compiler.
|
||||
// TODO(gri) remove in favor of uses of Constraint.
|
||||
@ -136,6 +128,23 @@ func bindTParams(list []*TypeName) *TypeParams {
|
||||
// ----------------------------------------------------------------------------
|
||||
// Implementation
|
||||
|
||||
// iface returns the constraint interface of t.
|
||||
func (t *TypeParam) iface() *Interface {
|
||||
if iface, _ := under(t.Constraint()).(*Interface); iface != nil {
|
||||
return iface
|
||||
}
|
||||
return &emptyInterface
|
||||
}
|
||||
|
||||
// structuralType returns the structural type of the type parameter's constraint; or nil.
|
||||
func (t *TypeParam) structuralType() Type {
|
||||
return t.iface().typeSet().structuralType()
|
||||
}
|
||||
|
||||
func (t *TypeParam) is(f func(*term) bool) bool {
|
||||
return t.iface().typeSet().is(f)
|
||||
}
|
||||
|
||||
func (t *TypeParam) underIs(f func(Type) bool) bool {
|
||||
return t.iface().typeSet().underIs(f)
|
||||
}
|
||||
|
||||
@ -18,31 +18,32 @@ import (
|
||||
type TypeSet struct {
|
||||
comparable bool // if set, the interface is or embeds comparable
|
||||
// TODO(gri) consider using a set for the methods for faster lookup
|
||||
methods []*Func // all methods of the interface; sorted by unique ID
|
||||
types Type // typically a *Union; nil means no type restrictions
|
||||
methods []*Func // all methods of the interface; sorted by unique ID
|
||||
terms termlist // type terms of the type set
|
||||
}
|
||||
|
||||
// IsTop reports whether type set s is the top type set (corresponding to the empty interface).
|
||||
func (s *TypeSet) IsTop() bool { return !s.comparable && len(s.methods) == 0 && s.types == nil }
|
||||
// IsEmpty reports whether type set s is the empty set.
|
||||
func (s *TypeSet) IsEmpty() bool { return s.terms.isEmpty() }
|
||||
|
||||
// IsTop reports whether type set s is the set of all types (corresponding to the empty interface).
|
||||
func (s *TypeSet) IsTop() bool { return !s.comparable && len(s.methods) == 0 && s.terms.isTop() }
|
||||
|
||||
// TODO(gri) IsMethodSet is not a great name for this predicate. Find a better one.
|
||||
|
||||
// IsMethodSet reports whether the type set s is described by a single set of methods.
|
||||
func (s *TypeSet) IsMethodSet() bool { return !s.comparable && s.types == nil }
|
||||
func (s *TypeSet) IsMethodSet() bool { return !s.comparable && s.terms.isTop() }
|
||||
|
||||
// IsComparable reports whether each type in the set is comparable.
|
||||
func (s *TypeSet) IsComparable() bool {
|
||||
if s.types == nil {
|
||||
if s.terms.isTop() {
|
||||
return s.comparable
|
||||
}
|
||||
tcomparable := s.underIs(func(u Type) bool {
|
||||
return Comparable(u)
|
||||
return s.is(func(t *term) bool {
|
||||
return Comparable(t.typ)
|
||||
})
|
||||
if !s.comparable {
|
||||
return tcomparable
|
||||
}
|
||||
return s.comparable && tcomparable
|
||||
}
|
||||
|
||||
// TODO(gri) IsTypeSet is not a great name. Find a better one.
|
||||
// TODO(gri) IsTypeSet is not a great name for this predicate. Find a better one.
|
||||
|
||||
// IsTypeSet reports whether the type set s is represented by a finite set of underlying types.
|
||||
func (s *TypeSet) IsTypeSet() bool {
|
||||
@ -63,15 +64,21 @@ func (s *TypeSet) LookupMethod(pkg *Package, name string) (int, *Func) {
|
||||
}
|
||||
|
||||
func (s *TypeSet) String() string {
|
||||
if s.IsTop() {
|
||||
switch {
|
||||
case s.IsEmpty():
|
||||
return "∅"
|
||||
case s.IsTop():
|
||||
return "⊤"
|
||||
}
|
||||
|
||||
hasMethods := len(s.methods) > 0
|
||||
hasTerms := s.hasTerms()
|
||||
|
||||
var buf bytes.Buffer
|
||||
buf.WriteByte('{')
|
||||
if s.comparable {
|
||||
buf.WriteString(" comparable")
|
||||
if len(s.methods) > 0 || s.types != nil {
|
||||
if hasMethods || hasTerms {
|
||||
buf.WriteByte(';')
|
||||
}
|
||||
}
|
||||
@ -82,41 +89,77 @@ func (s *TypeSet) String() string {
|
||||
buf.WriteByte(' ')
|
||||
buf.WriteString(m.String())
|
||||
}
|
||||
if len(s.methods) > 0 && s.types != nil {
|
||||
if hasMethods && hasTerms {
|
||||
buf.WriteByte(';')
|
||||
}
|
||||
if s.types != nil {
|
||||
buf.WriteByte(' ')
|
||||
writeType(&buf, s.types, nil, nil)
|
||||
if hasTerms {
|
||||
buf.WriteString(s.terms.String())
|
||||
}
|
||||
buf.WriteString(" }") // there was at least one method or term
|
||||
|
||||
buf.WriteString(" }") // there was a least one method or type
|
||||
return buf.String()
|
||||
}
|
||||
|
||||
// ----------------------------------------------------------------------------
|
||||
// Implementation
|
||||
|
||||
// underIs reports whether f returned true for the underlying types of the
|
||||
// enumerable types in the type set s. If the type set comprises all types
|
||||
// f is called once with the top type; if the type set is empty, the result
|
||||
// is false.
|
||||
func (s *TypeSet) underIs(f func(Type) bool) bool {
|
||||
switch t := s.types.(type) {
|
||||
case nil:
|
||||
return f(theTop)
|
||||
default:
|
||||
return f(t)
|
||||
case *Union:
|
||||
return t.underIs(f)
|
||||
func (s *TypeSet) hasTerms() bool { return !s.terms.isTop() }
|
||||
func (s *TypeSet) structuralType() Type { return s.terms.structuralType() }
|
||||
func (s *TypeSet) includes(t Type) bool { return s.terms.includes(t) }
|
||||
func (s1 *TypeSet) subsetOf(s2 *TypeSet) bool { return s1.terms.subsetOf(s2.terms) }
|
||||
|
||||
// TODO(gri) TypeSet.is and TypeSet.underIs should probably also go into termlist.go
|
||||
|
||||
var topTerm = term{false, theTop}
|
||||
|
||||
func (s *TypeSet) is(f func(*term) bool) bool {
|
||||
if len(s.terms) == 0 {
|
||||
return false
|
||||
}
|
||||
for _, t := range s.terms {
|
||||
// Terms represent the top term with a nil type.
|
||||
// The rest of the type checker uses the top type
|
||||
// instead. Convert.
|
||||
// TODO(gri) investigate if we can do without this
|
||||
if t.typ == nil {
|
||||
t = &topTerm
|
||||
}
|
||||
if !f(t) {
|
||||
return false
|
||||
}
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
func (s *TypeSet) underIs(f func(Type) bool) bool {
|
||||
if len(s.terms) == 0 {
|
||||
return false
|
||||
}
|
||||
for _, t := range s.terms {
|
||||
// see corresponding comment in TypeSet.is
|
||||
u := t.typ
|
||||
if u == nil {
|
||||
u = theTop
|
||||
}
|
||||
// t == under(t) for ~t terms
|
||||
if !t.tilde {
|
||||
u = under(u)
|
||||
}
|
||||
if debug {
|
||||
assert(Identical(u, under(u)))
|
||||
}
|
||||
if !f(u) {
|
||||
return false
|
||||
}
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
// topTypeSet may be used as type set for the empty interface.
|
||||
var topTypeSet TypeSet
|
||||
var topTypeSet = TypeSet{terms: topTermlist}
|
||||
|
||||
// computeTypeSet may be called with check == nil.
|
||||
func computeTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
|
||||
// computeInterfaceTypeSet may be called with check == nil.
|
||||
func computeInterfaceTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
|
||||
if ityp.tset != nil {
|
||||
return ityp.tset
|
||||
}
|
||||
@ -152,7 +195,7 @@ func computeTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
|
||||
// have valid interfaces. Mark the interface as complete to avoid
|
||||
// infinite recursion if the validType check occurs later for some
|
||||
// reason.
|
||||
ityp.tset = new(TypeSet) // TODO(gri) is this sufficient?
|
||||
ityp.tset = &TypeSet{terms: topTermlist} // TODO(gri) is this sufficient?
|
||||
|
||||
// Methods of embedded interfaces are collected unchanged; i.e., the identity
|
||||
// of a method I.m's Func Object of an interface I is the same as that of
|
||||
@ -213,7 +256,7 @@ func computeTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
|
||||
}
|
||||
|
||||
// collect embedded elements
|
||||
var allTypes Type
|
||||
var allTerms = topTermlist
|
||||
for i, typ := range ityp.embeddeds {
|
||||
// The embedding position is nil for imported interfaces
|
||||
// and also for interface copies after substitution (but
|
||||
@ -222,25 +265,22 @@ func computeTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
|
||||
if ityp.embedPos != nil {
|
||||
pos = (*ityp.embedPos)[i]
|
||||
}
|
||||
var types Type
|
||||
var terms termlist
|
||||
switch t := under(typ).(type) {
|
||||
case *Interface:
|
||||
tset := computeTypeSet(check, pos, t)
|
||||
tset := computeInterfaceTypeSet(check, pos, t)
|
||||
if tset.comparable {
|
||||
ityp.tset.comparable = true
|
||||
}
|
||||
for _, m := range tset.methods {
|
||||
addMethod(pos, m, false) // use embedding position pos rather than m.pos
|
||||
}
|
||||
types = tset.types
|
||||
terms = tset.terms
|
||||
case *Union:
|
||||
// TODO(gri) combine with default case once we have
|
||||
// converted all tests to new notation and we
|
||||
// can report an error when we don't have an
|
||||
// interface before go1.18.
|
||||
types = typ
|
||||
tset := computeUnionTypeSet(check, pos, t)
|
||||
terms = tset.terms
|
||||
case *TypeParam:
|
||||
// Embedding stand-alone type parameters is not permitted for now.
|
||||
// Embedding stand-alone type parameters is not permitted.
|
||||
// This case is handled during union parsing.
|
||||
unreachable()
|
||||
default:
|
||||
@ -251,9 +291,11 @@ func computeTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
|
||||
check.errorf(pos, "%s is not an interface", typ)
|
||||
continue
|
||||
}
|
||||
types = typ
|
||||
terms = termlist{{false, typ}}
|
||||
}
|
||||
allTypes = intersect(allTypes, types)
|
||||
// The type set of an interface is the intersection
|
||||
// of the type sets of all its elements.
|
||||
allTerms = allTerms.intersect(terms)
|
||||
}
|
||||
ityp.embedPos = nil // not needed anymore (errors have been reported)
|
||||
|
||||
@ -270,7 +312,7 @@ func computeTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet {
|
||||
sortMethods(methods)
|
||||
ityp.tset.methods = methods
|
||||
}
|
||||
ityp.tset.types = allTypes
|
||||
ityp.tset.terms = allTerms
|
||||
|
||||
return ityp.tset
|
||||
}
|
||||
@ -294,3 +336,34 @@ type byUniqueMethodName []*Func
|
||||
func (a byUniqueMethodName) Len() int { return len(a) }
|
||||
func (a byUniqueMethodName) Less(i, j int) bool { return a[i].less(&a[j].object) }
|
||||
func (a byUniqueMethodName) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
|
||||
|
||||
// computeUnionTypeSet may be called with check == nil.
|
||||
func computeUnionTypeSet(check *Checker, pos syntax.Pos, utyp *Union) *TypeSet {
|
||||
if utyp.tset != nil {
|
||||
return utyp.tset
|
||||
}
|
||||
|
||||
// avoid infinite recursion (see also computeInterfaceTypeSet)
|
||||
utyp.tset = new(TypeSet)
|
||||
|
||||
var allTerms termlist
|
||||
for _, t := range utyp.terms {
|
||||
var terms termlist
|
||||
switch u := under(t.typ).(type) {
|
||||
case *Interface:
|
||||
terms = computeInterfaceTypeSet(check, pos, u).terms
|
||||
case *TypeParam:
|
||||
// A stand-alone type parameters is not permitted as union term.
|
||||
// This case is handled during union parsing.
|
||||
unreachable()
|
||||
default:
|
||||
terms = termlist{t}
|
||||
}
|
||||
// The type set of a union expression is the union
|
||||
// of the type sets of each term.
|
||||
allTerms = allTerms.union(terms)
|
||||
}
|
||||
utyp.tset.terms = allTerms
|
||||
|
||||
return utyp.tset
|
||||
}
|
||||
|
||||
@ -158,9 +158,10 @@ func writeType(buf *bytes.Buffer, typ Type, qf Qualifier, visited []Type) {
|
||||
writeSignature(buf, t, qf, visited)
|
||||
|
||||
case *Union:
|
||||
if t.IsEmpty() {
|
||||
buf.WriteString("⊥")
|
||||
break
|
||||
// Unions only appear as (syntactic) embedded elements
|
||||
// in interfaces and syntactically cannot be empty.
|
||||
if t.NumTerms() == 0 {
|
||||
panic("internal error: empty union")
|
||||
}
|
||||
for i, t := range t.terms {
|
||||
if i > 0 {
|
||||
@ -198,13 +199,21 @@ func writeType(buf *bytes.Buffer, typ Type, qf Qualifier, visited []Type) {
|
||||
writeSignature(buf, m.typ.(*Signature), qf, visited)
|
||||
empty = false
|
||||
}
|
||||
if !empty && tset.types != nil {
|
||||
if !empty && tset.hasTerms() {
|
||||
buf.WriteString("; ")
|
||||
}
|
||||
if tset.types != nil {
|
||||
buf.WriteString("type ")
|
||||
writeType(buf, tset.types, qf, visited)
|
||||
}
|
||||
first := true
|
||||
tset.is(func(t *term) bool {
|
||||
if !first {
|
||||
buf.WriteByte('|')
|
||||
}
|
||||
first = false
|
||||
if t.tilde {
|
||||
buf.WriteByte('~')
|
||||
}
|
||||
writeType(buf, t.typ, qf, visited)
|
||||
return true
|
||||
})
|
||||
} else {
|
||||
// print explicit interface methods and embedded types
|
||||
for i, m := range t.methods {
|
||||
|
||||
@ -147,18 +147,18 @@ func (check *Checker) varType(e syntax.Expr) Type {
|
||||
// ordinaryType reports an error if typ is an interface type containing
|
||||
// type lists or is (or embeds) the predeclared type comparable.
|
||||
func (check *Checker) ordinaryType(pos syntax.Pos, typ Type) {
|
||||
// We don't want to call under() (via Interface) or complete interfaces while we
|
||||
// We don't want to call under() (via asInterface) or complete interfaces while we
|
||||
// are in the middle of type-checking parameter declarations that might belong to
|
||||
// interface methods. Delay this check to the end of type-checking.
|
||||
check.later(func() {
|
||||
if t := asInterface(typ); t != nil {
|
||||
tset := computeTypeSet(check, pos, t) // TODO(gri) is this the correct position?
|
||||
if tset.types != nil {
|
||||
check.softErrorf(pos, "interface contains type constraints (%s)", tset.types)
|
||||
return
|
||||
}
|
||||
if tset.IsComparable() {
|
||||
check.softErrorf(pos, "interface is (or embeds) comparable")
|
||||
tset := computeInterfaceTypeSet(check, pos, t) // TODO(gri) is this the correct position?
|
||||
if !tset.IsMethodSet() {
|
||||
if tset.comparable {
|
||||
check.softErrorf(pos, "interface is (or embeds) comparable")
|
||||
} else {
|
||||
check.softErrorf(pos, "interface contains type constraints")
|
||||
}
|
||||
}
|
||||
}
|
||||
})
|
||||
|
||||
@ -361,9 +361,6 @@ func (u *unifier) nify(x, y Type, p *ifacePair) bool {
|
||||
u.nify(x.results, y.results, p)
|
||||
}
|
||||
|
||||
case *Union:
|
||||
panic("unimplemented: unification with type sets described by types")
|
||||
|
||||
case *Interface:
|
||||
// Two interface types are identical if they have the same set of methods with
|
||||
// the same names and identical function types. Lower-case method names from
|
||||
@ -371,7 +368,7 @@ func (u *unifier) nify(x, y Type, p *ifacePair) bool {
|
||||
if y, ok := y.(*Interface); ok {
|
||||
xset := x.typeSet()
|
||||
yset := y.typeSet()
|
||||
if !Identical(xset.types, yset.types) {
|
||||
if !xset.terms.equal(yset.terms) {
|
||||
return false
|
||||
}
|
||||
a := xset.methods
|
||||
|
||||
@ -9,17 +9,17 @@ import "cmd/compile/internal/syntax"
|
||||
// ----------------------------------------------------------------------------
|
||||
// API
|
||||
|
||||
// A Union represents a union of terms.
|
||||
// A Union represents a union of terms embedded in an interface.
|
||||
type Union struct {
|
||||
terms []*term
|
||||
terms []*term // list of syntactical terms (not a canonicalized termlist)
|
||||
tset *TypeSet // type set described by this union, computed lazily
|
||||
}
|
||||
|
||||
// NewUnion returns a new Union type with the given terms (types[i], tilde[i]).
|
||||
// The lengths of both arguments must match. An empty union represents the set
|
||||
// of no types.
|
||||
// The lengths of both arguments must match. It is an error to create an empty
|
||||
// union; they are syntactically not possible.
|
||||
func NewUnion(types []Type, tilde []bool) *Union { return newUnion(types, tilde) }
|
||||
|
||||
func (u *Union) IsEmpty() bool { return len(u.terms) == 0 }
|
||||
func (u *Union) NumTerms() int { return len(u.terms) }
|
||||
func (u *Union) Term(i int) (Type, bool) { t := u.terms[i]; return t.typ, t.tilde }
|
||||
|
||||
@ -29,12 +29,10 @@ func (u *Union) String() string { return TypeString(u, nil) }
|
||||
// ----------------------------------------------------------------------------
|
||||
// Implementation
|
||||
|
||||
var emptyUnion = new(Union)
|
||||
|
||||
func newUnion(types []Type, tilde []bool) *Union {
|
||||
assert(len(types) == len(tilde))
|
||||
if len(types) == 0 {
|
||||
return emptyUnion
|
||||
panic("empty union")
|
||||
}
|
||||
t := new(Union)
|
||||
t.terms = make([]*term, len(types))
|
||||
@ -44,52 +42,23 @@ func newUnion(types []Type, tilde []bool) *Union {
|
||||
return t
|
||||
}
|
||||
|
||||
// is reports whether f returns true for all terms of u.
|
||||
func (u *Union) is(f func(*term) bool) bool {
|
||||
if u.IsEmpty() {
|
||||
return false
|
||||
}
|
||||
for _, t := range u.terms {
|
||||
if !f(t) {
|
||||
return false
|
||||
}
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
// underIs reports whether f returned true for the underlying types of all terms of u.
|
||||
func (u *Union) underIs(f func(Type) bool) bool {
|
||||
if u.IsEmpty() {
|
||||
return false
|
||||
}
|
||||
for _, t := range u.terms {
|
||||
if !f(under(t.typ)) {
|
||||
return false
|
||||
}
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
func parseUnion(check *Checker, tlist []syntax.Expr) Type {
|
||||
var types []Type
|
||||
var tilde []bool
|
||||
var terms []*term
|
||||
for _, x := range tlist {
|
||||
t, d := parseTilde(check, x)
|
||||
if len(tlist) == 1 && !d {
|
||||
return t // single type
|
||||
tilde, typ := parseTilde(check, x)
|
||||
if len(tlist) == 1 && !tilde {
|
||||
return typ // single type
|
||||
}
|
||||
types = append(types, t)
|
||||
tilde = append(tilde, d)
|
||||
terms = append(terms, &term{tilde, typ})
|
||||
}
|
||||
|
||||
// Ensure that each type is only present once in the type list.
|
||||
// It's ok to do this check later because it's not a requirement
|
||||
// for correctness of the code.
|
||||
// Check validity of terms.
|
||||
// Do this check later because it requires types to be set up.
|
||||
// Note: This is a quadratic algorithm, but unions tend to be short.
|
||||
check.later(func() {
|
||||
for i, t := range types {
|
||||
t := expand(t)
|
||||
if t == Typ[Invalid] {
|
||||
for i, t := range terms {
|
||||
typ := expand(t.typ)
|
||||
if typ == Typ[Invalid] {
|
||||
continue
|
||||
}
|
||||
|
||||
@ -105,16 +74,16 @@ func parseUnion(check *Checker, tlist []syntax.Expr) Type {
|
||||
}
|
||||
}
|
||||
|
||||
u := under(t)
|
||||
u := under(typ)
|
||||
f, _ := u.(*Interface)
|
||||
if tilde[i] {
|
||||
if t.tilde {
|
||||
if f != nil {
|
||||
check.errorf(x, "invalid use of ~ (%s is an interface)", t)
|
||||
check.errorf(x, "invalid use of ~ (%s is an interface)", typ)
|
||||
continue // don't report another error for t
|
||||
}
|
||||
|
||||
if !Identical(u, t) {
|
||||
check.errorf(x, "invalid use of ~ (underlying type of %s is %s)", t, u)
|
||||
if !Identical(u, typ) {
|
||||
check.errorf(x, "invalid use of ~ (underlying type of %s is %s)", typ, u)
|
||||
continue // don't report another error for t
|
||||
}
|
||||
}
|
||||
@ -127,19 +96,18 @@ func parseUnion(check *Checker, tlist []syntax.Expr) Type {
|
||||
continue // don't report another error for t
|
||||
}
|
||||
|
||||
// Complain about duplicate entries a|a, but also a|~a, and ~a|~a.
|
||||
// TODO(gri) We should also exclude myint|~int since myint is included in ~int.
|
||||
if includes(types[:i], t) {
|
||||
// TODO(gri) this currently doesn't print the ~ if present
|
||||
check.softErrorf(pos, "duplicate term %s in union element", t)
|
||||
// Report overlapping (non-disjoint) terms such as
|
||||
// a|a, a|~a, ~a|~a, and ~a|A (where under(A) == a).
|
||||
if j := overlappingTerm(terms[:i], t); j >= 0 {
|
||||
check.softErrorf(pos, "overlapping terms %s and %s", t, terms[j])
|
||||
}
|
||||
}
|
||||
})
|
||||
|
||||
return newUnion(types, tilde)
|
||||
return &Union{terms, nil}
|
||||
}
|
||||
|
||||
func parseTilde(check *Checker, x syntax.Expr) (typ Type, tilde bool) {
|
||||
func parseTilde(check *Checker, x syntax.Expr) (tilde bool, typ Type) {
|
||||
if op, _ := x.(*syntax.Operation); op != nil && op.Op == syntax.Tilde {
|
||||
x = op.X
|
||||
tilde = true
|
||||
@ -153,116 +121,20 @@ func parseTilde(check *Checker, x syntax.Expr) (typ Type, tilde bool) {
|
||||
return
|
||||
}
|
||||
|
||||
// intersect computes the intersection of the types x and y,
|
||||
// A nil type stands for the set of all types; an empty union
|
||||
// stands for the set of no types.
|
||||
func intersect(x, y Type) (r Type) {
|
||||
// If one of the types is nil (no restrictions)
|
||||
// the result is the other type.
|
||||
switch {
|
||||
case x == nil:
|
||||
return y
|
||||
case y == nil:
|
||||
return x
|
||||
}
|
||||
|
||||
// Compute the terms which are in both x and y.
|
||||
// TODO(gri) This is not correct as it may not always compute
|
||||
// the "largest" intersection. For instance, for
|
||||
// x = myInt|~int, y = ~int
|
||||
// we get the result myInt but we should get ~int.
|
||||
xu, _ := x.(*Union)
|
||||
yu, _ := y.(*Union)
|
||||
switch {
|
||||
case xu != nil && yu != nil:
|
||||
return &Union{intersectTerms(xu.terms, yu.terms)}
|
||||
|
||||
case xu != nil:
|
||||
if r, _ := xu.intersect(y, false); r != nil {
|
||||
return y
|
||||
}
|
||||
|
||||
case yu != nil:
|
||||
if r, _ := yu.intersect(x, false); r != nil {
|
||||
return x
|
||||
}
|
||||
|
||||
default: // xu == nil && yu == nil
|
||||
if Identical(x, y) {
|
||||
return x
|
||||
}
|
||||
}
|
||||
|
||||
return emptyUnion
|
||||
}
|
||||
|
||||
// includes reports whether typ is in list.
|
||||
func includes(list []Type, typ Type) bool {
|
||||
for _, e := range list {
|
||||
if Identical(typ, e) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// intersect computes the intersection of the union u and term (y, yt)
|
||||
// and returns the intersection term, if any. Otherwise the result is
|
||||
// (nil, false).
|
||||
// TODO(gri) this needs to cleaned up/removed once we switch to lazy
|
||||
// union type set computation.
|
||||
func (u *Union) intersect(y Type, yt bool) (Type, bool) {
|
||||
under_y := under(y)
|
||||
for _, x := range u.terms {
|
||||
xt := x.tilde
|
||||
// determine which types xx, yy to compare
|
||||
xx := x.typ
|
||||
if yt {
|
||||
xx = under(xx)
|
||||
}
|
||||
yy := y
|
||||
if xt {
|
||||
yy = under_y
|
||||
}
|
||||
if Identical(xx, yy) {
|
||||
// T ∩ T = T
|
||||
// T ∩ ~t = T
|
||||
// ~t ∩ T = T
|
||||
// ~t ∩ ~t = ~t
|
||||
return xx, xt && yt
|
||||
}
|
||||
}
|
||||
return nil, false
|
||||
}
|
||||
|
||||
func identicalTerms(list1, list2 []*term) bool {
|
||||
if len(list1) != len(list2) {
|
||||
return false
|
||||
}
|
||||
// Every term in list1 must be in list2.
|
||||
// Quadratic algorithm, but probably good enough for now.
|
||||
// TODO(gri) we need a fast quick type ID/hash for all types.
|
||||
L:
|
||||
for _, x := range list1 {
|
||||
for _, y := range list2 {
|
||||
if x.equal(y) {
|
||||
continue L // x is in list2
|
||||
// overlappingTerm reports the index of the term x in terms which is
|
||||
// overlapping (not disjoint) from y. The result is < 0 if there is no
|
||||
// such term.
|
||||
func overlappingTerm(terms []*term, y *term) int {
|
||||
for i, x := range terms {
|
||||
// disjoint requires non-nil, non-top arguments
|
||||
if debug {
|
||||
if x == nil || x.typ == nil || y == nil || y.typ == nil {
|
||||
panic("internal error: empty or top union term")
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
func intersectTerms(list1, list2 []*term) (list []*term) {
|
||||
// Quadratic algorithm, but good enough for now.
|
||||
// TODO(gri) fix asymptotic performance
|
||||
for _, x := range list1 {
|
||||
for _, y := range list2 {
|
||||
if r := x.intersect(y); r != nil {
|
||||
list = append(list, r)
|
||||
}
|
||||
if !x.disjoint(y) {
|
||||
return i
|
||||
}
|
||||
}
|
||||
return
|
||||
return -1
|
||||
}
|
||||
|
||||
@ -89,7 +89,7 @@ func defPredeclaredTypes() {
|
||||
sig := NewSignature(nil, nil, NewTuple(res), false)
|
||||
err := NewFunc(nopos, nil, "Error", sig)
|
||||
ityp := &Interface{obj, []*Func{err}, nil, nil, true, nil}
|
||||
computeTypeSet(nil, nopos, ityp) // prevent races due to lazy computation of tset
|
||||
computeInterfaceTypeSet(nil, nopos, ityp) // prevent races due to lazy computation of tset
|
||||
typ := NewNamed(obj, ityp, nil)
|
||||
sig.recv = NewVar(nopos, nil, "", typ)
|
||||
def(obj)
|
||||
@ -99,7 +99,7 @@ func defPredeclaredTypes() {
|
||||
{
|
||||
obj := NewTypeName(nopos, nil, "comparable", nil)
|
||||
obj.setColor(black)
|
||||
ityp := &Interface{obj, nil, nil, nil, true, &TypeSet{true, nil, nil}}
|
||||
ityp := &Interface{obj, nil, nil, nil, true, &TypeSet{true, nil, topTermlist}}
|
||||
NewNamed(obj, ityp, nil)
|
||||
def(obj)
|
||||
}
|
||||
|
||||
@ -28,11 +28,11 @@ func main() {
|
||||
}
|
||||
|
||||
const want2 = "ay"
|
||||
if got := a.Min[string]("bb", "ay"); got != want2 { // ERROR "string does not satisfy interface{int|int64|float64}"
|
||||
if got := a.Min[string]("bb", "ay"); got != want2 { // ERROR "string does not satisfy"
|
||||
panic(fmt.Sprintf("got %d, want %d", got, want2))
|
||||
}
|
||||
|
||||
if got := a.Min("bb", "ay"); got != want2 { // ERROR "string does not satisfy interface{int|int64|float64}"
|
||||
if got := a.Min("bb", "ay"); got != want2 { // ERROR "string does not satisfy"
|
||||
panic(fmt.Sprintf("got %d, want %d", got, want2))
|
||||
}
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user