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https://github.com/golang/go
synced 2024-09-15 14:10:17 +00:00
[dev.typeparams] cmd/compile/internal/types2: adjust unsafe.Alignof/Offsetof/Sizeof
Changed the implementation such that the result is a variable rather than a constant if the argument type (or the struct in case of unsafe.Offsetof) has a size that depends on type parameters. Minor unrelated adjustments. For #40301. Change-Id: I1e988f1479b95648ad95a455c764ead829d75749 Reviewed-on: https://go-review.googlesource.com/c/go/+/335413 Trust: Robert Griesemer <gri@golang.org> Run-TryBot: Robert Griesemer <gri@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
parent
fca3e5c445
commit
80127a7dfe
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@ -624,19 +624,22 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
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case _Alignof:
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case _Alignof:
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// unsafe.Alignof(x T) uintptr
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// unsafe.Alignof(x T) uintptr
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if asTypeParam(x.typ) != nil {
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check.errorf(call, invalidOp+"unsafe.Alignof undefined for %s", x)
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return
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}
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check.assignment(x, nil, "argument to unsafe.Alignof")
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check.assignment(x, nil, "argument to unsafe.Alignof")
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if x.mode == invalid {
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if x.mode == invalid {
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return
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return
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}
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}
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if hasVarSize(x.typ) {
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x.mode = value
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if check.Types != nil {
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check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], x.typ))
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}
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} else {
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x.mode = constant_
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x.mode = constant_
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x.val = constant.MakeInt64(check.conf.alignof(x.typ))
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x.val = constant.MakeInt64(check.conf.alignof(x.typ))
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x.typ = Typ[Uintptr]
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// result is constant - no need to record signature
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// result is constant - no need to record signature
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}
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x.typ = Typ[Uintptr]
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case _Offsetof:
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case _Offsetof:
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// unsafe.Offsetof(x T) uintptr, where x must be a selector
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// unsafe.Offsetof(x T) uintptr, where x must be a selector
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@ -674,30 +677,43 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
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return
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return
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}
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}
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// TODO(gri) Should we pass x.typ instead of base (and indirect report if derefStructPtr indirected)?
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// TODO(gri) Should we pass x.typ instead of base (and have indirect report if derefStructPtr indirected)?
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check.recordSelection(selx, FieldVal, base, obj, index, false)
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check.recordSelection(selx, FieldVal, base, obj, index, false)
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offs := check.conf.offsetof(base, index)
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// The field offset is considered a variable even if the field is declared before
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// the part of the struct which is variable-sized. This makes both the rules
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// simpler and also permits (or at least doesn't prevent) a compiler from re-
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// arranging struct fields if it wanted to.
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if hasVarSize(base) {
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x.mode = value
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if check.Types != nil {
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check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], obj.Type()))
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}
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} else {
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x.mode = constant_
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x.mode = constant_
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x.val = constant.MakeInt64(offs)
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x.val = constant.MakeInt64(check.conf.offsetof(base, index))
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x.typ = Typ[Uintptr]
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// result is constant - no need to record signature
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// result is constant - no need to record signature
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}
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x.typ = Typ[Uintptr]
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case _Sizeof:
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case _Sizeof:
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// unsafe.Sizeof(x T) uintptr
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// unsafe.Sizeof(x T) uintptr
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if asTypeParam(x.typ) != nil {
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check.errorf(call, invalidOp+"unsafe.Sizeof undefined for %s", x)
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return
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}
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check.assignment(x, nil, "argument to unsafe.Sizeof")
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check.assignment(x, nil, "argument to unsafe.Sizeof")
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if x.mode == invalid {
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if x.mode == invalid {
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return
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return
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}
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}
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if hasVarSize(x.typ) {
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x.mode = value
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if check.Types != nil {
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check.recordBuiltinType(call.Fun, makeSig(Typ[Uintptr], x.typ))
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}
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} else {
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x.mode = constant_
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x.mode = constant_
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x.val = constant.MakeInt64(check.conf.sizeof(x.typ))
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x.val = constant.MakeInt64(check.conf.sizeof(x.typ))
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x.typ = Typ[Uintptr]
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// result is constant - no need to record signature
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// result is constant - no need to record signature
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}
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x.typ = Typ[Uintptr]
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case _Slice:
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case _Slice:
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// unsafe.Slice(ptr *T, len IntegerType) []T
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// unsafe.Slice(ptr *T, len IntegerType) []T
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@ -769,6 +785,25 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
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return true
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return true
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}
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}
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// hasVarSize reports if the size of type t is variable due to type parameters.
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func hasVarSize(t Type) bool {
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switch t := under(t).(type) {
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case *Array:
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return hasVarSize(t.elem)
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case *Struct:
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for _, f := range t.fields {
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if hasVarSize(f.typ) {
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return true
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}
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}
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case *TypeParam:
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return true
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case *Named, *Union, *instance, *top:
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unreachable()
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}
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return false
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}
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// applyTypeFunc applies f to x. If x is a type parameter,
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// applyTypeFunc applies f to x. If x is a type parameter,
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// the result is a type parameter constrained by an new
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// the result is a type parameter constrained by an new
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// interface bound. The type bounds for that interface
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// interface bound. The type bounds for that interface
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@ -7,6 +7,7 @@ package types2_test
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import (
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import (
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"cmd/compile/internal/syntax"
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"cmd/compile/internal/syntax"
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"fmt"
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"fmt"
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"strings"
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"testing"
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"testing"
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. "cmd/compile/internal/types2"
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. "cmd/compile/internal/types2"
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@ -111,12 +112,15 @@ var builtinCalls = []struct {
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{"Alignof", `_ = unsafe.Alignof(0)`, `invalid type`}, // constant
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{"Alignof", `_ = unsafe.Alignof(0)`, `invalid type`}, // constant
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{"Alignof", `var x struct{}; _ = unsafe.Alignof(x)`, `invalid type`}, // constant
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{"Alignof", `var x struct{}; _ = unsafe.Alignof(x)`, `invalid type`}, // constant
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{"Alignof", `var x P; _ = unsafe.Alignof(x)`, `func(p.P₁) uintptr`},
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{"Offsetof", `var x struct{f bool}; _ = unsafe.Offsetof(x.f)`, `invalid type`}, // constant
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{"Offsetof", `var x struct{f bool}; _ = unsafe.Offsetof(x.f)`, `invalid type`}, // constant
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{"Offsetof", `var x struct{_ int; f bool}; _ = unsafe.Offsetof((&x).f)`, `invalid type`}, // constant
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{"Offsetof", `var x struct{_ int; f bool}; _ = unsafe.Offsetof((&x).f)`, `invalid type`}, // constant
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{"Offsetof", `var x struct{_ int; f P}; _ = unsafe.Offsetof((&x).f)`, `func(p.P₁) uintptr`},
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{"Sizeof", `_ = unsafe.Sizeof(0)`, `invalid type`}, // constant
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{"Sizeof", `_ = unsafe.Sizeof(0)`, `invalid type`}, // constant
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{"Sizeof", `var x struct{}; _ = unsafe.Sizeof(x)`, `invalid type`}, // constant
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{"Sizeof", `var x struct{}; _ = unsafe.Sizeof(x)`, `invalid type`}, // constant
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{"Sizeof", `var x P; _ = unsafe.Sizeof(x)`, `func(p.P₁) uintptr`},
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{"Slice", `var p *int; _ = unsafe.Slice(p, 1)`, `func(*int, int) []int`},
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{"Slice", `var p *int; _ = unsafe.Slice(p, 1)`, `func(*int, int) []int`},
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{"Slice", `var p *byte; var n uintptr; _ = unsafe.Slice(p, n)`, `func(*byte, uintptr) []byte`},
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{"Slice", `var p *byte; var n uintptr; _ = unsafe.Slice(p, n)`, `func(*byte, uintptr) []byte`},
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@ -149,9 +153,14 @@ func TestBuiltinSignatures(t *testing.T) {
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}
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}
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}
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}
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func parseGenericSrc(path, src string) (*syntax.File, error) {
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errh := func(error) {} // dummy error handler so that parsing continues in presence of errors
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return syntax.Parse(syntax.NewFileBase(path), strings.NewReader(src), errh, nil, syntax.AllowGenerics)
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}
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func testBuiltinSignature(t *testing.T, name, src0, want string) {
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func testBuiltinSignature(t *testing.T, name, src0, want string) {
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src := fmt.Sprintf(`package p; import "unsafe"; type _ unsafe.Pointer /* use unsafe */; func _() { %s }`, src0)
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src := fmt.Sprintf(`package p; import "unsafe"; type _ unsafe.Pointer /* use unsafe */; func _[P any]() { %s }`, src0)
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f, err := parseSrc("", src)
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f, err := parseGenericSrc("", src)
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if err != nil {
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if err != nil {
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t.Errorf("%s: %s", src0, err)
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t.Errorf("%s: %s", src0, err)
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return
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return
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@ -401,8 +401,8 @@ func (check *Checker) inferB(tparams []*TypeName, targs []Type, report bool) (ty
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// u.x.types() now contains the incoming type arguments plus any additional type
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// u.x.types() now contains the incoming type arguments plus any additional type
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// arguments for which there were structural constraints. The newly inferred non-
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// arguments for which there were structural constraints. The newly inferred non-
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// nil entries may still contain references to other type parameters. For instance,
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// nil entries may still contain references to other type parameters.
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// for [A any, B interface{type []C}, C interface{type *A}], if A == int
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// For instance, for [A any, B interface{ []C }, C interface{ *A }], if A == int
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// was given, unification produced the type list [int, []C, *A]. We eliminate the
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// was given, unification produced the type list [int, []C, *A]. We eliminate the
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// remaining type parameters by substituting the type parameters in this type list
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// remaining type parameters by substituting the type parameters in this type list
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// until nothing changes anymore.
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// until nothing changes anymore.
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@ -48,7 +48,7 @@ type StdSizes struct {
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func (s *StdSizes) Alignof(T Type) int64 {
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func (s *StdSizes) Alignof(T Type) int64 {
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// For arrays and structs, alignment is defined in terms
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// For arrays and structs, alignment is defined in terms
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// of alignment of the elements and fields, respectively.
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// of alignment of the elements and fields, respectively.
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switch t := optype(T).(type) {
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switch t := under(T).(type) {
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case *Array:
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case *Array:
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// spec: "For a variable x of array type: unsafe.Alignof(x)
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// spec: "For a variable x of array type: unsafe.Alignof(x)
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// is the same as unsafe.Alignof(x[0]), but at least 1."
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// is the same as unsafe.Alignof(x[0]), but at least 1."
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@ -73,6 +73,8 @@ func (s *StdSizes) Alignof(T Type) int64 {
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if t.Info()&IsString != 0 {
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if t.Info()&IsString != 0 {
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return s.WordSize
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return s.WordSize
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}
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}
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case *TypeParam, *Union:
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unreachable()
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}
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}
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a := s.Sizeof(T) // may be 0
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a := s.Sizeof(T) // may be 0
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// spec: "For a variable x of any type: unsafe.Alignof(x) is at least 1."
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// spec: "For a variable x of any type: unsafe.Alignof(x) is at least 1."
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@ -118,7 +120,7 @@ var basicSizes = [...]byte{
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}
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}
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func (s *StdSizes) Sizeof(T Type) int64 {
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func (s *StdSizes) Sizeof(T Type) int64 {
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switch t := optype(T).(type) {
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switch t := under(T).(type) {
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case *Basic:
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case *Basic:
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assert(isTyped(T))
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assert(isTyped(T))
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k := t.kind
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k := t.kind
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@ -148,10 +150,10 @@ func (s *StdSizes) Sizeof(T Type) int64 {
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}
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}
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offsets := s.Offsetsof(t.fields)
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offsets := s.Offsetsof(t.fields)
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return offsets[n-1] + s.Sizeof(t.fields[n-1].typ)
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return offsets[n-1] + s.Sizeof(t.fields[n-1].typ)
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case *Union:
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panic("Sizeof unimplemented for union")
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case *Interface:
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case *Interface:
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return s.WordSize * 2
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return s.WordSize * 2
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case *TypeParam, *Union:
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unreachable()
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}
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}
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return s.WordSize // catch-all
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return s.WordSize // catch-all
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}
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}
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@ -6,6 +6,8 @@
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package builtins
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package builtins
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import "unsafe"
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// close
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// close
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type C0 interface{ int }
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type C0 interface{ int }
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@ -127,3 +129,108 @@ func _[T Bss]() {
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_ = make(T, 10)
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_ = make(T, 10)
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_ = make(T, 10, 20)
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_ = make(T, 10, 20)
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}
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}
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// unsafe.Alignof
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func _[T comparable]() {
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var (
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b int64
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a [10]T
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s struct{ f T }
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p *T
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l []T
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f func(T)
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i interface{ m() T }
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c chan T
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m map[T]T
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t T
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)
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const bb = unsafe.Alignof(b)
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assert(bb == 8)
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const _ = unsafe /* ERROR not constant */ .Alignof(a)
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const _ = unsafe /* ERROR not constant */ .Alignof(s)
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const pp = unsafe.Alignof(p)
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assert(pp == 8)
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const ll = unsafe.Alignof(l)
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assert(ll == 8)
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const ff = unsafe.Alignof(f)
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assert(ff == 8)
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const ii = unsafe.Alignof(i)
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assert(ii == 8)
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const cc = unsafe.Alignof(c)
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assert(cc == 8)
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const mm = unsafe.Alignof(m)
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assert(mm == 8)
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const _ = unsafe /* ERROR not constant */ .Alignof(t)
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}
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// unsafe.Offsetof
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func _[T comparable]() {
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var (
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b struct{ _, f int64 }
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a struct{ _, f [10]T }
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s struct{ _, f struct{ f T } }
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p struct{ _, f *T }
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l struct{ _, f []T }
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f struct{ _, f func(T) }
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i struct{ _, f interface{ m() T } }
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c struct{ _, f chan T }
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m struct{ _, f map[T]T }
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t struct{ _, f T }
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)
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const bb = unsafe.Offsetof(b.f)
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assert(bb == 8)
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const _ = unsafe /* ERROR not constant */ .Alignof(a)
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const _ = unsafe /* ERROR not constant */ .Alignof(s)
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const pp = unsafe.Offsetof(p.f)
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assert(pp == 8)
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const ll = unsafe.Offsetof(l.f)
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assert(ll == 24)
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const ff = unsafe.Offsetof(f.f)
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assert(ff == 8)
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const ii = unsafe.Offsetof(i.f)
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assert(ii == 16)
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const cc = unsafe.Offsetof(c.f)
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assert(cc == 8)
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const mm = unsafe.Offsetof(m.f)
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assert(mm == 8)
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const _ = unsafe /* ERROR not constant */ .Alignof(t)
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}
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// unsafe.Sizeof
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func _[T comparable]() {
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var (
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b int64
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a [10]T
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s struct{ f T }
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p *T
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l []T
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f func(T)
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i interface{ m() T }
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c chan T
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m map[T]T
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t T
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)
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const bb = unsafe.Sizeof(b)
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assert(bb == 8)
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const _ = unsafe /* ERROR not constant */ .Alignof(a)
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const _ = unsafe /* ERROR not constant */ .Alignof(s)
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const pp = unsafe.Sizeof(p)
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assert(pp == 8)
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const ll = unsafe.Sizeof(l)
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assert(ll == 24)
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const ff = unsafe.Sizeof(f)
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assert(ff == 8)
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const ii = unsafe.Sizeof(i)
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assert(ii == 16)
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const cc = unsafe.Sizeof(c)
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assert(cc == 8)
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const mm = unsafe.Sizeof(m)
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assert(mm == 8)
|
||||||
|
const _ = unsafe /* ERROR not constant */ .Alignof(t)
|
||||||
|
}
|
||||||
|
|
|
@ -7,6 +7,6 @@ package p
|
||||||
import "unsafe"
|
import "unsafe"
|
||||||
|
|
||||||
func _[T any](x T) {
|
func _[T any](x T) {
|
||||||
_ = unsafe /* ERROR undefined */ .Alignof(x)
|
_ = unsafe.Alignof(x)
|
||||||
_ = unsafe /* ERROR undefined */ .Sizeof(x)
|
_ = unsafe.Sizeof(x)
|
||||||
}
|
}
|
||||||
|
|
Loading…
Reference in a new issue