diff --git a/src/cmd/compile/internal/types2/interface.go b/src/cmd/compile/internal/types2/interface.go index e667830db3..18dc573340 100644 --- a/src/cmd/compile/internal/types2/interface.go +++ b/src/cmd/compile/internal/types2/interface.go @@ -4,11 +4,7 @@ package types2 -import ( - "cmd/compile/internal/syntax" - "fmt" - "sort" -) +import "cmd/compile/internal/syntax" func (check *Checker) interfaceType(ityp *Interface, iface *syntax.InterfaceType, def *Named) { var tlist []syntax.Expr // types collected from all type lists @@ -128,187 +124,3 @@ func flattenUnion(list []syntax.Expr, x syntax.Expr) []syntax.Expr { } return append(list, x) } - -// newTypeSet may be called with check == nil. -// TODO(gri) move this function into typeset.go eventually -func newTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet { - if ityp.tset != nil { - return ityp.tset - } - - // If the interface is not fully set up yet, the type set will - // not be complete, which may lead to errors when using the the - // type set (e.g. missing method). Don't compute a partial type - // set (and don't store it!), so that we still compute the full - // type set eventually. Instead, return the top type set and - // let any follow-on errors play out. - // - // TODO(gri) Consider recording when this happens and reporting - // it as an error (but only if there were no other errors so to - // to not have unnecessary follow-on errors). - if !ityp.complete { - return &topTypeSet - } - - if check != nil && check.conf.Trace { - // Types don't generally have position information. - // If we don't have a valid pos provided, try to use - // one close enough. - if !pos.IsKnown() && len(ityp.methods) > 0 { - pos = ityp.methods[0].pos - } - - check.trace(pos, "type set for %s", ityp) - check.indent++ - defer func() { - check.indent-- - check.trace(pos, "=> %s ", ityp.typeSet()) - }() - } - - // An infinitely expanding interface (due to a cycle) is detected - // elsewhere (Checker.validType), so here we simply assume we only - // 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? - - // 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 - // the method m in an interface that embeds interface I. On the other hand, - // if a method is embedded via multiple overlapping embedded interfaces, we - // don't provide a guarantee which "original m" got chosen for the embedding - // interface. See also issue #34421. - // - // If we don't care to provide this identity guarantee anymore, instead of - // reusing the original method in embeddings, we can clone the method's Func - // Object and give it the position of a corresponding embedded interface. Then - // we can get rid of the mpos map below and simply use the cloned method's - // position. - - var todo []*Func - var seen objset - var methods []*Func - mpos := make(map[*Func]syntax.Pos) // method specification or method embedding position, for good error messages - addMethod := func(pos syntax.Pos, m *Func, explicit bool) { - switch other := seen.insert(m); { - case other == nil: - methods = append(methods, m) - mpos[m] = pos - case explicit: - if check == nil { - panic(fmt.Sprintf("%s: duplicate method %s", m.pos, m.name)) - } - // check != nil - var err error_ - err.errorf(pos, "duplicate method %s", m.name) - err.errorf(mpos[other.(*Func)], "other declaration of %s", m.name) - check.report(&err) - default: - // We have a duplicate method name in an embedded (not explicitly declared) method. - // Check method signatures after all types are computed (issue #33656). - // If we're pre-go1.14 (overlapping embeddings are not permitted), report that - // error here as well (even though we could do it eagerly) because it's the same - // error message. - if check == nil { - // check method signatures after all locally embedded interfaces are computed - todo = append(todo, m, other.(*Func)) - break - } - // check != nil - check.later(func() { - if !check.allowVersion(m.pkg, 1, 14) || !Identical(m.typ, other.Type()) { - var err error_ - err.errorf(pos, "duplicate method %s", m.name) - err.errorf(mpos[other.(*Func)], "other declaration of %s", m.name) - check.report(&err) - } - }) - } - } - - for _, m := range ityp.methods { - addMethod(m.pos, m, true) - } - - // collect embedded elements - var allTypes Type - for i, typ := range ityp.embeddeds { - // The embedding position is nil for imported interfaces - // and also for interface copies after substitution (but - // in that case we don't need to report errors again). - var pos syntax.Pos // embedding position - if ityp.embedPos != nil { - pos = (*ityp.embedPos)[i] - } - var types Type - switch t := under(typ).(type) { - case *Interface: - tset := newTypeSet(check, pos, t) - for _, m := range tset.methods { - addMethod(pos, m, false) // use embedding position pos rather than m.pos - } - types = tset.types - 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 - case *TypeParam: - if check != nil && !check.allowVersion(check.pkg, 1, 18) { - check.errorf(pos, "%s is a type parameter, not an interface", typ) - continue - } - types = typ - default: - if typ == Typ[Invalid] { - continue - } - if check != nil && !check.allowVersion(check.pkg, 1, 18) { - check.errorf(pos, "%s is not an interface", typ) - continue - } - types = typ - } - allTypes = intersect(allTypes, types) - } - ityp.embedPos = nil // not needed anymore (errors have been reported) - - // process todo's (this only happens if check == nil) - for i := 0; i < len(todo); i += 2 { - m := todo[i] - other := todo[i+1] - if !Identical(m.typ, other.typ) { - panic(fmt.Sprintf("%s: duplicate method %s", m.pos, m.name)) - } - } - - if methods != nil { - sortMethods(methods) - ityp.tset.methods = methods - } - ityp.tset.types = allTypes - - return ityp.tset -} - -func sortMethods(list []*Func) { - sort.Sort(byUniqueMethodName(list)) -} - -func assertSortedMethods(list []*Func) { - if !debug { - panic("internal error: assertSortedMethods called outside debug mode") - } - if !sort.IsSorted(byUniqueMethodName(list)) { - panic("internal error: methods not sorted") - } -} - -// byUniqueMethodName method lists can be sorted by their unique method names. -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] } diff --git a/src/cmd/compile/internal/types2/typeset.go b/src/cmd/compile/internal/types2/typeset.go index 44e5929413..ce4a776f8f 100644 --- a/src/cmd/compile/internal/types2/typeset.go +++ b/src/cmd/compile/internal/types2/typeset.go @@ -6,10 +6,13 @@ package types2 import ( "bytes" + "cmd/compile/internal/syntax" + "fmt" + "sort" ) -// topTypeSet may be used as type set for the empty interface. -var topTypeSet TypeSet +// ---------------------------------------------------------------------------- +// API // A TypeSet represents the type set of an interface. type TypeSet struct { @@ -18,6 +21,31 @@ type TypeSet struct { types Type // typically a *Union; nil means no type restrictions } +// IsTop reports whether type set s is the top type set (corresponding to the empty interface). +func (s *TypeSet) IsTop() bool { return len(s.methods) == 0 && s.types == nil } + +// IsMethodSet reports whether the type set s is described by a single set of methods. +func (s *TypeSet) IsMethodSet() bool { return s.types == nil && !s.IsComparable() } + +// IsComparable reports whether each type in the set is comparable. +func (s *TypeSet) IsComparable() bool { + _, m := s.LookupMethod(nil, "==") + return m != nil +} + +// NumMethods returns the number of methods available. +func (s *TypeSet) NumMethods() int { return len(s.methods) } + +// Method returns the i'th method of type set s for 0 <= i < s.NumMethods(). +// The methods are ordered by their unique ID. +func (s *TypeSet) Method(i int) *Func { return s.methods[i] } + +// LookupMethod returns the index of and method with matching package and name, or (-1, nil). +func (s *TypeSet) LookupMethod(pkg *Package, name string) (int, *Func) { + // TODO(gri) s.methods is sorted - consider binary search + return lookupMethod(s.methods, pkg, name) +} + func (s *TypeSet) String() string { if s.IsTop() { return "⊤" @@ -44,27 +72,187 @@ func (s *TypeSet) String() string { return buf.String() } -// IsTop reports whether type set s is the top type set (corresponding to the empty interface). -func (s *TypeSet) IsTop() bool { return len(s.methods) == 0 && s.types == nil } +// ---------------------------------------------------------------------------- +// Implementation -// IsMethodSet reports whether the type set s is described by a single set of methods. -func (s *TypeSet) IsMethodSet() bool { return s.types == nil && !s.IsComparable() } +// topTypeSet may be used as type set for the empty interface. +var topTypeSet TypeSet -// IsComparable reports whether each type in the set is comparable. -func (s *TypeSet) IsComparable() bool { - _, m := s.LookupMethod(nil, "==") - return m != nil +// newTypeSet may be called with check == nil. +func newTypeSet(check *Checker, pos syntax.Pos, ityp *Interface) *TypeSet { + if ityp.tset != nil { + return ityp.tset + } + + // If the interface is not fully set up yet, the type set will + // not be complete, which may lead to errors when using the the + // type set (e.g. missing method). Don't compute a partial type + // set (and don't store it!), so that we still compute the full + // type set eventually. Instead, return the top type set and + // let any follow-on errors play out. + if !ityp.complete { + return &topTypeSet + } + + if check != nil && check.conf.Trace { + // Types don't generally have position information. + // If we don't have a valid pos provided, try to use + // one close enough. + if !pos.IsKnown() && len(ityp.methods) > 0 { + pos = ityp.methods[0].pos + } + + check.trace(pos, "type set for %s", ityp) + check.indent++ + defer func() { + check.indent-- + check.trace(pos, "=> %s ", ityp.typeSet()) + }() + } + + // An infinitely expanding interface (due to a cycle) is detected + // elsewhere (Checker.validType), so here we simply assume we only + // 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? + + // 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 + // the method m in an interface that embeds interface I. On the other hand, + // if a method is embedded via multiple overlapping embedded interfaces, we + // don't provide a guarantee which "original m" got chosen for the embedding + // interface. See also issue #34421. + // + // If we don't care to provide this identity guarantee anymore, instead of + // reusing the original method in embeddings, we can clone the method's Func + // Object and give it the position of a corresponding embedded interface. Then + // we can get rid of the mpos map below and simply use the cloned method's + // position. + + var todo []*Func + var seen objset + var methods []*Func + mpos := make(map[*Func]syntax.Pos) // method specification or method embedding position, for good error messages + addMethod := func(pos syntax.Pos, m *Func, explicit bool) { + switch other := seen.insert(m); { + case other == nil: + methods = append(methods, m) + mpos[m] = pos + case explicit: + if check == nil { + panic(fmt.Sprintf("%s: duplicate method %s", m.pos, m.name)) + } + // check != nil + var err error_ + err.errorf(pos, "duplicate method %s", m.name) + err.errorf(mpos[other.(*Func)], "other declaration of %s", m.name) + check.report(&err) + default: + // We have a duplicate method name in an embedded (not explicitly declared) method. + // Check method signatures after all types are computed (issue #33656). + // If we're pre-go1.14 (overlapping embeddings are not permitted), report that + // error here as well (even though we could do it eagerly) because it's the same + // error message. + if check == nil { + // check method signatures after all locally embedded interfaces are computed + todo = append(todo, m, other.(*Func)) + break + } + // check != nil + check.later(func() { + if !check.allowVersion(m.pkg, 1, 14) || !Identical(m.typ, other.Type()) { + var err error_ + err.errorf(pos, "duplicate method %s", m.name) + err.errorf(mpos[other.(*Func)], "other declaration of %s", m.name) + check.report(&err) + } + }) + } + } + + for _, m := range ityp.methods { + addMethod(m.pos, m, true) + } + + // collect embedded elements + var allTypes Type + for i, typ := range ityp.embeddeds { + // The embedding position is nil for imported interfaces + // and also for interface copies after substitution (but + // in that case we don't need to report errors again). + var pos syntax.Pos // embedding position + if ityp.embedPos != nil { + pos = (*ityp.embedPos)[i] + } + var types Type + switch t := under(typ).(type) { + case *Interface: + tset := newTypeSet(check, pos, t) + for _, m := range tset.methods { + addMethod(pos, m, false) // use embedding position pos rather than m.pos + } + types = tset.types + 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 + case *TypeParam: + if check != nil && !check.allowVersion(check.pkg, 1, 18) { + check.errorf(pos, "%s is a type parameter, not an interface", typ) + continue + } + types = typ + default: + if typ == Typ[Invalid] { + continue + } + if check != nil && !check.allowVersion(check.pkg, 1, 18) { + check.errorf(pos, "%s is not an interface", typ) + continue + } + types = typ + } + allTypes = intersect(allTypes, types) + } + ityp.embedPos = nil // not needed anymore (errors have been reported) + + // process todo's (this only happens if check == nil) + for i := 0; i < len(todo); i += 2 { + m := todo[i] + other := todo[i+1] + if !Identical(m.typ, other.typ) { + panic(fmt.Sprintf("%s: duplicate method %s", m.pos, m.name)) + } + } + + if methods != nil { + sortMethods(methods) + ityp.tset.methods = methods + } + ityp.tset.types = allTypes + + return ityp.tset } -// NumMethods returns the number of methods available. -func (s *TypeSet) NumMethods() int { return len(s.methods) } - -// Method returns the i'th method of type set s for 0 <= i < s.NumMethods(). -// The methods are ordered by their unique ID. -func (s *TypeSet) Method(i int) *Func { return s.methods[i] } - -// LookupMethod returns the index of and method with matching package and name, or (-1, nil). -func (s *TypeSet) LookupMethod(pkg *Package, name string) (int, *Func) { - // TODO(gri) s.methods is sorted - consider binary search - return lookupMethod(s.methods, pkg, name) +func sortMethods(list []*Func) { + sort.Sort(byUniqueMethodName(list)) } + +func assertSortedMethods(list []*Func) { + if !debug { + panic("internal error: assertSortedMethods called outside debug mode") + } + if !sort.IsSorted(byUniqueMethodName(list)) { + panic("internal error: methods not sorted") + } +} + +// byUniqueMethodName method lists can be sorted by their unique method names. +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] }