diff options
| -rw-r--r-- | src/cmd/compile/internal/types2/signature.go | 8 | ||||
| -rw-r--r-- | src/cmd/compile/internal/types2/testdata/fixedbugs/issue47968.go2 | 21 |
2 files changed, 28 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/types2/signature.go b/src/cmd/compile/internal/types2/signature.go index d28e7b8944..ddad1f0311 100644 --- a/src/cmd/compile/internal/types2/signature.go +++ b/src/cmd/compile/internal/types2/signature.go @@ -132,7 +132,7 @@ func (check *Checker) funcType(sig *Signature, recvPar *syntax.Field, tparams [] // Also: Don't report an error via genericType since it will be reported // again when we type-check the signature. // TODO(gri) maybe the receiver should be marked as invalid instead? - if recv := asNamed(check.genericType(rname, false)); recv != nil { + if recv, _ := check.genericType(rname, false).(*Named); recv != nil { recvTParams = recv.TParams().list() } } @@ -211,6 +211,12 @@ func (check *Checker) funcType(sig *Signature, recvPar *syntax.Field, tparams [] switch T := rtyp.(type) { case *Named: T.expand(nil) + // The receiver type may be an instantiated type referred to + // by an alias (which cannot have receiver parameters for now). + if T.TArgs() != nil && sig.RParams() == nil { + check.errorf(recv.pos, "cannot define methods on instantiated type %s", recv.typ) + break + } // spec: "The type denoted by T is called the receiver base type; it must not // be a pointer or interface type and it must be declared in the same package // as the method." diff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47968.go2 b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47968.go2 new file mode 100644 index 0000000000..bbbe6805f2 --- /dev/null +++ b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47968.go2 @@ -0,0 +1,21 @@ +// 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 p + +type T[P any] struct{} + +func (T[P]) m1() + +type A1 = T + +func (A1[P]) m2() {} + +type A2 = T[int] + +func (A2 /* ERROR cannot define methods on instantiated type T\[int\] */) m3() {} +func (_ /* ERROR cannot define methods on instantiated type T\[int\] */ A2) m4() {} + +func (T[int]) m5() {} // int is the type parameter name, not an instantiation +func (T[* /* ERROR must be an identifier */ int]) m6() {} // syntax error |