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go/types, types2: disallow real, imag, complex on type parameters

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We can type-check these fine but the API implications are unclear.

Fixes #50912.
For #50937.

Change-Id: If29bbb4a257ff6a85e3bfcd4755fd8f90c80fb87
Reviewed-on: https://go-review.googlesource.com/c/go/+/382116
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
This commit is contained in:
Robert Griesemer 2022-01-31 15:12:53 -08:00
parent eab9a77a60
commit 4fea5935f5
7 changed files with 127 additions and 18 deletions
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18
src/cmd/compile/internal/types2/builtins.go
View file

@ -309,7 +309,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
}
return nil
}
resTyp := check.applyTypeFunc(f, x.typ)
resTyp := check.applyTypeFunc(f, x, id)
if resTyp == nil {
check.errorf(x, invalidArg+"arguments have type %s, expected floating-point", x.typ)
return
@ -437,7 +437,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
}
return nil
}
resTyp := check.applyTypeFunc(f, x.typ)
resTyp := check.applyTypeFunc(f, x, id)
if resTyp == nil {
check.errorf(x, invalidArg+"argument has type %s, expected complex type", x.typ)
return
@ -800,8 +800,8 @@ func hasVarSize(t Type) bool {
// of x. If any of these applications of f return nil,
// applyTypeFunc returns nil.
// If x is not a type parameter, the result is f(x).
func (check *Checker) applyTypeFunc(f func(Type) Type, x Type) Type {
if tp, _ := x.(*TypeParam); tp != nil {
func (check *Checker) applyTypeFunc(f func(Type) Type, x *operand, id builtinId) Type {
if tp, _ := x.typ.(*TypeParam); tp != nil {
// Test if t satisfies the requirements for the argument
// type and collect possible result types at the same time.
var terms []*Term
@ -818,17 +818,23 @@ func (check *Checker) applyTypeFunc(f func(Type) Type, x Type) Type {
return nil
}
// We can type-check this fine but we're introducing a synthetic
// type parameter for the result. It's not clear what the API
// implications are here. Report an error for 1.18 but continue
// type-checking.
check.softErrorf(x, "%s not supported as argument to %s for go1.18 (see issue #50937)", x, predeclaredFuncs[id].name)
// Construct a suitable new type parameter for the result type.
// The type parameter is placed in the current package so export/import
// works as expected.
tpar := NewTypeName(nopos, check.pkg, "<type parameter>", nil)
tpar := NewTypeName(nopos, check.pkg, tp.obj.name, nil)
ptyp := check.newTypeParam(tpar, NewInterfaceType(nil, []Type{NewUnion(terms)})) // assigns type to tpar as a side-effect
ptyp.index = tp.index
return ptyp
}
return f(x)
return f(x.typ)
}
// makeSig makes a signature for the given argument and result types.

19
src/cmd/compile/internal/types2/testdata/fixedbugs/issue50912.go2 vendored Normal file
View file

@ -0,0 +1,19 @@
// Copyright 2022 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
func Real[P ~complex128](x P) {
_ = real(x /* ERROR not supported */ )
}
func Imag[P ~complex128](x P) {
_ = imag(x /* ERROR not supported */ )
}
func Complex[P ~float64](x P) {
_ = complex(x /* ERROR not supported */ , 0)
_ = complex(0 /* ERROR not supported */ , x)
_ = complex(x /* ERROR not supported */ , x)
}

29
src/go/types/builtins.go
View file

@ -314,7 +314,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
}
return nil
}
resTyp := check.applyTypeFunc(f, x.typ)
resTyp := check.applyTypeFunc(f, x, id)
if resTyp == nil {
check.invalidArg(x, _InvalidComplex, "arguments have type %s, expected floating-point", x.typ)
return
@ -442,7 +442,7 @@ func (check *Checker) builtin(x *operand, call *ast.CallExpr, id builtinId) (_ b
}
return nil
}
resTyp := check.applyTypeFunc(f, x.typ)
resTyp := check.applyTypeFunc(f, x, id)
if resTyp == nil {
code := _InvalidImag
if id == _Real {
@ -809,8 +809,8 @@ func hasVarSize(t Type) bool {
// of x. If any of these applications of f return nil,
// applyTypeFunc returns nil.
// If x is not a type parameter, the result is f(x).
func (check *Checker) applyTypeFunc(f func(Type) Type, x Type) Type {
if tp, _ := x.(*TypeParam); tp != nil {
func (check *Checker) applyTypeFunc(f func(Type) Type, x *operand, id builtinId) Type {
if tp, _ := x.typ.(*TypeParam); tp != nil {
// Test if t satisfies the requirements for the argument
// type and collect possible result types at the same time.
var terms []*Term
@ -827,17 +827,34 @@ func (check *Checker) applyTypeFunc(f func(Type) Type, x Type) Type {
return nil
}
// We can type-check this fine but we're introducing a synthetic
// type parameter for the result. It's not clear what the API
// implications are here. Report an error for 1.18 (see #50912),
// but continue type-checking.
var code errorCode
switch id {
case _Real:
code = _InvalidReal
case _Imag:
code = _InvalidImag
case _Complex:
code = _InvalidComplex
default:
unreachable()
}
check.softErrorf(x, code, "%s not supported as argument to %s for go1.18 (see issue #50937)", x, predeclaredFuncs[id].name)
// Construct a suitable new type parameter for the result type.
// The type parameter is placed in the current package so export/import
// works as expected.
tpar := NewTypeName(token.NoPos, check.pkg, "<type parameter>", nil)
tpar := NewTypeName(token.NoPos, check.pkg, tp.obj.name, nil)
ptyp := check.newTypeParam(tpar, NewInterfaceType(nil, []Type{NewUnion(terms)})) // assigns type to tpar as a side-effect
ptyp.index = tp.index
return ptyp
}
return f(x)
return f(x.typ)
}
// makeSig makes a signature for the given argument and result types.

19
src/go/types/testdata/fixedbugs/issue50912.go2 vendored Normal file
View file

@ -0,0 +1,19 @@
// Copyright 2022 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
func Real[P ~complex128](x P) {
_ = real(x /* ERROR not supported */ )
}
func Imag[P ~complex128](x P) {
_ = imag(x /* ERROR not supported */ )
}
func Complex[P ~float64](x P) {
_ = complex(x /* ERROR not supported */ , 0)
_ = complex(0 /* ERROR not supported */ , x)
_ = complex(x /* ERROR not supported */ , x)
}

20
test/typeparam/absdiff2.go
View file

@ -66,9 +66,25 @@ type complexAbs[T Complex] struct {
Value T
}
func realimag(x any) (re, im float64) {
switch z := x.(type) {
case complex64:
re = float64(real(z))
im = float64(imag(z))
case complex128:
re = real(z)
im = imag(z)
default:
panic("unknown complex type")
}
return
}
func (a complexAbs[T]) Abs() T {
r := float64(real(a.Value))
i := float64(imag(a.Value))
// TODO use direct conversion instead of realimag once #50937 is fixed
r, i := realimag(a.Value)
// r := float64(real(a.Value))
// i := float64(imag(a.Value))
d := math.Sqrt(r*r + i*i)
return T(complex(d, 0))
}

20
test/typeparam/absdiff3.go
View file

@ -43,9 +43,25 @@ type Complex interface {
~complex64 | ~complex128
}
func realimag(x any) (re, im float64) {
switch z := x.(type) {
case complex64:
re = float64(real(z))
im = float64(imag(z))
case complex128:
re = real(z)
im = imag(z)
default:
panic("unknown complex type")
}
return
}
func ComplexAbs[T Complex](a T) T {
r := float64(real(a))
i := float64(imag(a))
// TODO use direct conversion instead of realimag once #50937 is fixed
r, i := realimag(a)
// r := float64(real(a))
// i := float64(imag(a))
d := math.Sqrt(r*r + i*i)
return T(complex(d, 0))
}

20
test/typeparam/absdiffimp2.dir/a.go
View file

@ -60,9 +60,25 @@ type complexAbs[T Complex] struct {
Value T
}
func realimag(x any) (re, im float64) {
switch z := x.(type) {
case complex64:
re = float64(real(z))
im = float64(imag(z))
case complex128:
re = real(z)
im = imag(z)
default:
panic("unknown complex type")
}
return
}
func (a complexAbs[T]) Abs() T {
r := float64(real(a.Value))
i := float64(imag(a.Value))
// TODO use direct conversion instead of realimag once #50937 is fixed
r, i := realimag(a.Value)
// r := float64(real(a.Value))
// i := float64(imag(a.Value))
d := math.Sqrt(r*r + i*i)
return T(complex(d, 0))
}