diff options
| -rw-r--r-- | src/cmd/compile/internal/types2/decl.go | 85 | ||||
| -rw-r--r-- | src/cmd/compile/internal/types2/signature.go | 7 | ||||
| -rw-r--r-- | src/cmd/compile/internal/types2/testdata/fixedbugs/issue40789.go2 | 37 | ||||
| -rw-r--r-- | src/cmd/compile/internal/types2/type.go | 6 |
4 files changed, 76 insertions, 59 deletions
diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go index 00b4ef7010..d36da06f42 100644 --- a/src/cmd/compile/internal/types2/decl.go +++ b/src/cmd/compile/internal/types2/decl.go @@ -674,75 +674,52 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *Named } -func (check *Checker) collectTypeParams(list []*syntax.Field) (tparams []*TypeName) { - // Type parameter lists should not be empty. The parser will - // complain but we still may get an incorrect AST: ignore it. - if len(list) == 0 { - return - } +func (check *Checker) collectTypeParams(list []*syntax.Field) []*TypeName { + tparams := make([]*TypeName, len(list)) - // Declare type parameters up-front, with empty interface as type bound. + // Declare type parameters up-front. // The scope of type parameters starts at the beginning of the type parameter - // list (so we can have mutually recursive parameterized interfaces). - for _, f := range list { - tparams = check.declareTypeParam(tparams, f.Name) + // list (so we can have mutually recursive parameterized type bounds). + for i, f := range list { + tparams[i] = check.declareTypeParam(i, f.Name) } var bound Type - for i, j := 0, 0; i < len(list); i = j { - f := list[i] - - // determine the range of type parameters list[i:j] with identical type bound - // (declared as in (type a, b, c B)) - j = i + 1 - for j < len(list) && list[j].Type == f.Type { - j++ - } - - // this should never be the case, but be careful - if f.Type == nil { - continue - } - - // The predeclared identifier "any" is visible only as a constraint - // in a type parameter list. Look for it before general constraint - // resolution. - if tident, _ := unparen(f.Type).(*syntax.Name); tident != nil && tident.Value == "any" && check.lookup("any") == nil { - bound = universeAny - } else { - bound = check.typ(f.Type) - } - - // type bound must be an interface - // TODO(gri) We should delay the interface check because - // we may not have a complete interface yet: - // type C(type T C) interface {} - // (issue #39724). - if _, ok := under(bound).(*Interface); ok { - // set the type bounds - for i < j { - tparams[i].typ.(*TypeParam).bound = bound - i++ - } - } else if bound != Typ[Invalid] { - check.errorf(f.Type, "%s is not an interface", bound) + for i, f := range list { + // Optimization: Re-use the previous type bound if it hasn't changed. + // This also preserves the grouped output of type parameter lists + // when printing type strings. + if i == 0 || f.Type != list[i-1].Type { + bound = check.boundType(f.Type) } + tparams[i].typ.(*TypeParam).bound = bound } - return + return tparams } -func (check *Checker) declareTypeParam(tparams []*TypeName, name *syntax.Name) []*TypeName { +func (check *Checker) declareTypeParam(index int, name *syntax.Name) *TypeName { tpar := NewTypeName(name.Pos(), check.pkg, name.Value, nil) - check.NewTypeParam(tpar, len(tparams), &emptyInterface) // assigns type to tpar as a side-effect + check.NewTypeParam(tpar, index, nil) // assigns type to tpar as a side-effect check.declare(check.scope, name, tpar, check.scope.pos) // TODO(gri) check scope position - tparams = append(tparams, tpar) + return tpar +} - if check.conf.Trace { - check.trace(name.Pos(), "type param = %v", tparams[len(tparams)-1]) +// boundType type-checks the type expression e and returns its type, or Typ[Invalid]. +// The type must be an interface, including the predeclared type "any". +func (check *Checker) boundType(e syntax.Expr) Type { + // The predeclared identifier "any" is visible only as a type bound in a type parameter list. + if name, _ := unparen(e).(*syntax.Name); name != nil && name.Value == "any" && check.lookup("any") == nil { + return universeAny } - return tparams + bound := check.typ(e) + check.later(func() { + if _, ok := under(bound).(*Interface); !ok && bound != Typ[Invalid] { + check.errorf(e, "%s is not an interface", bound) + } + }) + return bound } func (check *Checker) collectMethods(obj *TypeName) { diff --git a/src/cmd/compile/internal/types2/signature.go b/src/cmd/compile/internal/types2/signature.go index a7edc5ac03..01158187ba 100644 --- a/src/cmd/compile/internal/types2/signature.go +++ b/src/cmd/compile/internal/types2/signature.go @@ -48,10 +48,9 @@ func (check *Checker) funcType(sig *Signature, recvPar *syntax.Field, tparams [] // blank identifiers were found => use rewritten receiver type recvTyp = isubst(recvPar.Type, smap) } - // TODO(gri) rework declareTypeParams - sig.rparams = nil - for _, rparam := range rparams { - sig.rparams = check.declareTypeParam(sig.rparams, rparam) + sig.rparams = make([]*TypeName, len(rparams)) + for i, rparam := range rparams { + sig.rparams[i] = check.declareTypeParam(i, rparam) } // determine receiver type to get its type parameters // and the respective type parameter bounds diff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue40789.go2 b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue40789.go2 new file mode 100644 index 0000000000..9eea4ad60a --- /dev/null +++ b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue40789.go2 @@ -0,0 +1,37 @@ +// Copyright 2021 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import "fmt" + +func main() { + m := map[string]int{ + "a": 6, + "b": 7, + } + fmt.Println(copyMap[map[string]int, string, int](m)) +} + +type Map[K comparable, V any] interface { + map[K] V +} + +func copyMap[M Map[K, V], K comparable, V any](m M) M { + m1 := make(M) + for k, v := range m { + m1[k] = v + } + return m1 +} + +// simpler test case from the same issue + +type A[X comparable] interface { + []X +} + +func f[B A[X], X comparable]() B { + return nil +} diff --git a/src/cmd/compile/internal/types2/type.go b/src/cmd/compile/internal/types2/type.go index 2cfcabbdb5..05e6d77d22 100644 --- a/src/cmd/compile/internal/types2/type.go +++ b/src/cmd/compile/internal/types2/type.go @@ -626,7 +626,11 @@ func (t *TypeParam) SetId(id uint64) { } func (t *TypeParam) Bound() *Interface { - iface := asInterface(t.bound) + // we may not have an interface (error reported elsewhere) + iface, _ := under(t.bound).(*Interface) + if iface == nil { + return &emptyInterface + } // use the type bound position if we have one pos := nopos if n, _ := t.bound.(*Named); n != nil { |