mirror
/
go
mirror of https://github.com/golang/go.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

go/types: disallow lone type parameter on RHS of type declaration 

This is a clean port of CL 359177 to go/types.

Change-Id: I6c1574e3a1c23ea326eb8d4aacea0e78415703ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/360758
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This commit is contained in:
Robert Findley 2021-11-02 11:42:54 -04:00
parent 80065cf2f6
commit ea403bc237
13 changed files with 143 additions and 145 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/go/types/api_test.go
View File

@ -604,13 +604,6 @@ func TestDefsInfo(t *testing.T) {
{`package p3; type x int`, `x`, `type p3.x int`},
{`package p4; func f()`, `f`, `func p4.f()`},
{`package p5; func f() int { x, _ := 1, 2; return x }`, `_`, `var _ int`},
// generic types must be sanitized
// (need to use sufficiently nested types to provoke unexpanded types)
{genericPkg + `g0; type t[P any] P; const x = t[int](42)`, `x`, `const generic_g0.x generic_g0.t[int]`},
{genericPkg + `g1; type t[P any] P; var x = t[int](42)`, `x`, `var generic_g1.x generic_g1.t[int]`},
{genericPkg + `g2; type t[P any] P; type x struct{ f t[int] }`, `x`, `type generic_g2.x struct{f generic_g2.t[int]}`},
{genericPkg + `g3; type t[P any] P; func f(x struct{ f t[string] }); var g = f`, `g`, `var generic_g3.g func(x struct{f generic_g3.t[string]})`},
}
for _, test := range tests {
@ -649,13 +642,6 @@ func TestUsesInfo(t *testing.T) {
{`package p2; func _() { _ = x }; var x int`, `x`, `var p2.x int`},
{`package p3; func _() { type _ x }; type x int`, `x`, `type p3.x int`},
{`package p4; func _() { _ = f }; func f()`, `f`, `func p4.f()`},
// generic types must be sanitized
// (need to use sufficiently nested types to provoke unexpanded types)
{genericPkg + `g0; func _() { _ = x }; type t[P any] P; const x = t[int](42)`, `x`, `const generic_g0.x generic_g0.t[int]`},
{genericPkg + `g1; func _() { _ = x }; type t[P any] P; var x = t[int](42)`, `x`, `var generic_g1.x generic_g1.t[int]`},
{genericPkg + `g2; func _() { type _ x }; type t[P any] P; type x struct{ f t[int] }`, `x`, `type generic_g2.x struct{f generic_g2.t[int]}`},
{genericPkg + `g3; func _() { _ = f }; type t[P any] P; func f(x struct{ f t[string] })`, `f`, `func generic_g3.f(x struct{f generic_g3.t[string]})`},
}
for _, test := range tests {

9
src/go/types/decl.go
View File

@ -653,9 +653,12 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *ast.TypeSpec, def *Named) {
named.underlying = Typ[Invalid]
}
// If the RHS is a type parameter, it must be from this type declaration.
if tpar, _ := named.underlying.(*TypeParam); tpar != nil && tparamIndex(named.TypeParams().list(), tpar) < 0 {
check.errorf(tdecl.Type, _Todo, "cannot use function type parameter %s as RHS in type declaration", tpar)
// Disallow a lone type parameter as the RHS of a type declaration (issue #45639).
// We can look directly at named.underlying because even if it is still a *Named
// type (underlying not fully resolved yet) it cannot become a type parameter due
// to this very restriction.
if tpar, _ := named.underlying.(*TypeParam); tpar != nil {
check.error(tdecl.Type, _Todo, "cannot use a type parameter as RHS in type declaration")
named.underlying = Typ[Invalid]
}
}

61
src/go/types/testdata/check/linalg.go2 vendored
View File

@ -4,8 +4,6 @@
package linalg
import "math"
// Numeric is type bound that matches any numeric type.
// It would likely be in a constraints package in the standard library.
type Numeric interface {
@ -52,32 +50,33 @@ type Complex interface {
~complex64 | ~complex128
}
// OrderedAbs is a helper type that defines an Abs method for
// ordered numeric types.
type OrderedAbs[T OrderedNumeric] T
func (a OrderedAbs[T]) Abs() OrderedAbs[T] {
if a < 0 {
return -a
}
return a
}
// ComplexAbs is a helper type that defines an Abs method for
// complex types.
type ComplexAbs[T Complex] T
func (a ComplexAbs[T]) Abs() ComplexAbs[T] {
r := float64(real(a))
i := float64(imag(a))
d := math.Sqrt(r * r + i * i)
return ComplexAbs[T](complex(d, 0))
}
func OrderedAbsDifference[T OrderedNumeric](a, b T) T {
return T(AbsDifference(OrderedAbs[T](a), OrderedAbs[T](b)))
}
func ComplexAbsDifference[T Complex](a, b T) T {
return T(AbsDifference(ComplexAbs[T](a), ComplexAbs[T](b)))
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// // OrderedAbs is a helper type that defines an Abs method for
// // ordered numeric types.
// type OrderedAbs[T OrderedNumeric] T
//
// func (a OrderedAbs[T]) Abs() OrderedAbs[T] {
// if a < 0 {
// return -a
// }
// return a
// }
//
// // ComplexAbs is a helper type that defines an Abs method for
// // complex types.
// type ComplexAbs[T Complex] T
//
// func (a ComplexAbs[T]) Abs() ComplexAbs[T] {
// r := float64(real(a))
// i := float64(imag(a))
// d := math.Sqrt(r * r + i * i)
// return ComplexAbs[T](complex(d, 0))
// }
//
// func OrderedAbsDifference[T OrderedNumeric](a, b T) T {
// return T(AbsDifference(OrderedAbs[T](a), OrderedAbs[T](b)))
// }
//
// func ComplexAbsDifference[T Complex](a, b T) T {
// return T(AbsDifference(ComplexAbs[T](a), ComplexAbs[T](b)))
// }

5
src/go/types/testdata/check/typeinst.go2 vendored
View File

@ -8,7 +8,8 @@ type myInt int
// Parameterized type declarations
type T1[P any] P
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
type T1[P any] P // ERROR cannot use a type parameter as RHS in type declaration
type T2[P any] struct {
f P
@ -19,7 +20,7 @@ type List[P any] []P
// Alias type declarations cannot have type parameters.
// Issue #46477 proposses to change that.
type A1[P any] = /* ERROR cannot be alias */ P
type A1[P any] = /* ERROR cannot be alias */ struct{}
// Pending clarification of #46477 we disallow aliases
// of generic types.

30
src/go/types/testdata/check/typeinst2.go2 vendored
View File

@ -87,25 +87,27 @@ type NumericAbs[T any] interface {
func AbsDifference[T NumericAbs[T]](x T) { panic(0) }
type OrderedAbs[T any] T
func (a OrderedAbs[T]) Abs() OrderedAbs[T]
func OrderedAbsDifference[T any](x T) {
AbsDifference(OrderedAbs[T](x))
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// type OrderedAbs[T any] T
//
// func (a OrderedAbs[T]) Abs() OrderedAbs[T]
//
// func OrderedAbsDifference[T any](x T) {
// AbsDifference(OrderedAbs[T](x))
// }
// same code, reduced to essence
func g[P interface{ m() P }](x P) { panic(0) }
type T4[P any] P
func (_ T4[P]) m() T4[P]
func _[Q any](x Q) {
g(T4[Q](x))
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// type T4[P any] P
//
// func (_ T4[P]) m() T4[P]
//
// func _[Q any](x Q) {
// g(T4[Q](x))
// }
// Another test case that caused problems in the past

19
src/go/types/testdata/check/typeparams.go2 vendored
View File

@ -352,15 +352,16 @@ func _() {
// the previous example was extracted from
func f12[T interface{m() T}]() {}
type A[T any] T
func (a A[T]) m() A[T]
func _[T any]() {
f12[A[T]]()
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// func f12[T interface{m() T}]() {}
//
// type A[T any] T
//
// func (a A[T]) m() A[T]
//
// func _[T any]() {
// f12[A[T]]()
// }
// method expressions

31
src/go/types/testdata/examples/methods.go2 vendored
View File

@ -6,8 +6,6 @@
package p
import "unsafe"
// Parameterized types may have methods.
type T1[A any] struct{ a A }
@ -97,17 +95,18 @@ type T0 struct{}
func (T0) _() {}
func (T1[A]) _() {}
// A generic receiver type may constrain its type parameter such
// that it must be a pointer type. Such receiver types are not
// permitted.
type T3a[P interface{ ~int | ~string | ~float64 }] P
func (T3a[_]) m() {} // this is ok
type T3b[P interface{ ~unsafe.Pointer }] P
func (T3b /* ERROR invalid receiver */ [_]) m() {}
type T3c[P interface{ *int | *string }] P
func (T3c /* ERROR invalid receiver */ [_]) m() {}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// // A generic receiver type may constrain its type parameter such
// // that it must be a pointer type. Such receiver types are not
// // permitted.
// type T3a[P interface{ ~int | ~string | ~float64 }] P
//
// func (T3a[_]) m() {} // this is ok
//
// type T3b[P interface{ ~unsafe.Pointer }] P
//
// func (T3b /* ERROR invalid receiver */ [_]) m() {}
//
// type T3c[P interface{ *int | *string }] P
//
// func (T3c /* ERROR invalid receiver */ [_]) m() {}

13
src/go/types/testdata/examples/types.go2 vendored
View File

@ -191,12 +191,13 @@ type _ struct {
// _ = y < 0
//}
// It is not permitted to declare a local type whose underlying
// type is a type parameter not declared by that type declaration.
func _[T any]() {
type _ T // ERROR cannot use function type parameter T as RHS in type declaration
type _ [_ any] T // ERROR cannot use function type parameter T as RHS in type declaration
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// // It is not permitted to declare a local type whose underlying
// // type is a type parameter not declared by that type declaration.
// func _[T any]() {
// type _ T // ERROR cannot use function type parameter T as RHS in type declaration
// type _ [_ any] T // ERROR cannot use function type parameter T as RHS in type declaration
// }
// As a special case, an explicit type argument may be omitted
// from a type parameter bound if the type bound expects exactly

7
src/go/types/testdata/fixedbugs/issue39634.go2 vendored
View File

@ -74,9 +74,10 @@ func F20[t Z20]() { F20(t /* ERROR invalid composite literal type */ {}) }
type Z21 /* ERROR illegal cycle */ interface{ Z21 }
func F21[T Z21]() { ( /* ERROR not used */ F21[Z21]) }
// crash 24
type T24[P any] P
func (r T24[P]) m() { T24 /* ERROR without instantiation */ .m() }
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// // crash 24
// type T24[P any] P
// func (r T24[P]) m() { T24 /* ERROR without instantiation */ .m() }
// crash 25
type T25[A any] int

17
src/go/types/testdata/fixedbugs/issue39768.go2 vendored
View File

@ -4,14 +4,15 @@
package p
type T[P any] P
type A = T // ERROR cannot use generic type
var x A[int]
var _ A
type B = T[int]
var y B = x
var _ B /* ERROR not a generic type */ [int]
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// type T[P any] P
// type A = T // ERROR cannot use generic type
// var x A[int]
// var _ A
//
// type B = T[int]
// var y B = x
// var _ B /* ERROR not a generic type */ [int]
// test case from issue

2
src/go/types/testdata/fixedbugs/issue39938.go2 vendored
View File

@ -8,7 +8,7 @@
package p
type E0[P any] P
type E0[P any] []P
type E1[P any] *P
type E2[P any] struct{ _ P }
type E3[P any] struct{ _ *P }

13
src/go/types/testdata/fixedbugs/issue45639.go2 vendored
View File

@ -4,9 +4,10 @@
package P
// It is not permitted to declare a local type whose underlying
// type is a type parameters not declared by that type declaration.
func _[T any]() {
type _ T // ERROR cannot use function type parameter T as RHS in type declaration
type _ [_ any] T // ERROR cannot use function type parameter T as RHS in type declaration
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// // It is not permitted to declare a local type whose underlying
// // type is a type parameters not declared by that type declaration.
// func _[T any]() {
// type _ T // ERROR cannot use function type parameter T as RHS in type declaration
// type _ [_ any] T // ERROR cannot use function type parameter T as RHS in type declaration
// }

67
src/go/types/testdata/fixedbugs/issue47747.go2 vendored
View File

@ -4,15 +4,16 @@
package p
type T1[P any] P
func (T1[_]) m() {}
func _[P any](x *T1[P]) {
// x.m exists because x is of type *T1 where T1 is a defined type
// (even though under(T1) is a type parameter)
x.m()
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// type T1[P any] P
//
// func (T1[_]) m() {}
//
// func _[P any](x *T1[P]) {
// // x.m exists because x is of type *T1 where T1 is a defined type
// // (even though under(T1) is a type parameter)
// x.m()
// }
func _[P interface{ m() }](x P) {
@ -40,29 +41,31 @@ type Barer[t any] interface {
Bar(t)
}
type Foo1[t any] t
type Bar[t any] t
func (l Foo1[t]) Foo(v Barer[t]) { v.Bar(t(l)) }
func (b *Bar[t]) Bar(l t) { *b = Bar[t](l) }
func _[t any](f Fooer1[t]) t {
var b Bar[t]
f.Foo(&b)
return t(b)
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// type Foo1[t any] t
// type Bar[t any] t
//
// func (l Foo1[t]) Foo(v Barer[t]) { v.Bar(t(l)) }
// func (b *Bar[t]) Bar(l t) { *b = Bar[t](l) }
//
// func _[t any](f Fooer1[t]) t {
// var b Bar[t]
// f.Foo(&b)
// return t(b)
// }
// Test case 2 from issue
type Fooer2[t any] interface {
Foo()
}
type Foo2[t any] t
func (f *Foo2[t]) Foo() {}
func _[t any](v t) {
var f = Foo2[t](v)
_ = Fooer2[t](&f)
}
// For now, a lone type parameter is not permitted as RHS in a type declaration (issue #45639).
// type Fooer2[t any] interface {
// Foo()
// }
//
// type Foo2[t any] t
//
// func (f *Foo2[t]) Foo() {}
//
// func _[t any](v t) {
// var f = Foo2[t](v)
// _ = Fooer2[t](&f)
// }