constraints package
- The new constraints package
- defines a set of useful constraints that can be used with type parameters of
- generic functions.
-
debug/buildinfo packagediff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47818.go2 b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47818.go2 index 2631118baed94..546de1ce31345 100644 --- a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47818.go2 +++ b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47818.go2 @@ -8,8 +8,6 @@ package go1_17 -import "constraints" - type T[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ] struct{} // for init (and main, but we're not in package main) we should only get one error @@ -57,5 +55,3 @@ type ( _ = C1 _ = C2 ) - -type Ordered constraints /* ERROR using type constraint constraints\.Ordered requires go1\.18 or later */ .Ordered diff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue49705.go2 b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue49705.go2 index 2b991b872211a..5b5fba2a1dc66 100644 --- a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue49705.go2 +++ b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue49705.go2 @@ -4,8 +4,11 @@ package p -import "constraints" +type Integer interface { + ~int | ~int8 | ~int16 | ~int32 | ~int64 | + ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr +} -func shl[I constraints.Integer](n int) I { +func shl[I Integer](n int) I { return 1 << n } diff --git a/src/constraints/constraints.go b/src/constraints/constraints.go deleted file mode 100644 index 2c033dff47e90..0000000000000 --- a/src/constraints/constraints.go +++ /dev/null @@ -1,50 +0,0 @@ -// 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 constraints defines a set of useful constraints to be used -// with type parameters. -package constraints - -// Signed is a constraint that permits any signed integer type. -// If future releases of Go add new predeclared signed integer types, -// this constraint will be modified to include them. -type Signed interface { - ~int | ~int8 | ~int16 | ~int32 | ~int64 -} - -// Unsigned is a constraint that permits any unsigned integer type. -// If future releases of Go add new predeclared unsigned integer types, -// this constraint will be modified to include them. -type Unsigned interface { - ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr -} - -// Integer is a constraint that permits any integer type. -// If future releases of Go add new predeclared integer types, -// this constraint will be modified to include them. -type Integer interface { - Signed | Unsigned -} - -// Float is a constraint that permits any floating-point type. -// If future releases of Go add new predeclared floating-point types, -// this constraint will be modified to include them. -type Float interface { - ~float32 | ~float64 -} - -// Complex is a constraint that permits any complex numeric type. -// If future releases of Go add new predeclared complex numeric types, -// this constraint will be modified to include them. -type Complex interface { - ~complex64 | ~complex128 -} - -// Ordered is a constraint that permits any ordered type: any type -// that supports the operators < <= >= >. -// If future releases of Go add new ordered types, -// this constraint will be modified to include them. -type Ordered interface { - Integer | Float | ~string -} diff --git a/src/constraints/constraints_test.go b/src/constraints/constraints_test.go deleted file mode 100644 index 47d4cba52a078..0000000000000 --- a/src/constraints/constraints_test.go +++ /dev/null @@ -1,117 +0,0 @@ -// 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 constraints - -import ( - "bytes" - "fmt" - "internal/testenv" - "os" - "os/exec" - "path/filepath" - "testing" -) - -type ( - testSigned[T Signed] struct{ f T } - testUnsigned[T Unsigned] struct{ f T } - testInteger[T Integer] struct{ f T } - testFloat[T Float] struct{ f T } - testComplex[T Complex] struct{ f T } - testOrdered[T Ordered] struct{ f T } -) - -// TestTypes passes if it compiles. -type TestTypes struct { - _ testSigned[int] - _ testSigned[int64] - _ testUnsigned[uint] - _ testUnsigned[uintptr] - _ testInteger[int8] - _ testInteger[uint8] - _ testInteger[uintptr] - _ testFloat[float32] - _ testComplex[complex64] - _ testOrdered[int] - _ testOrdered[float64] - _ testOrdered[string] -} - -var prolog = []byte(` -package constrainttest - -import "constraints" - -type ( - testSigned[T constraints.Signed] struct{ f T } - testUnsigned[T constraints.Unsigned] struct{ f T } - testInteger[T constraints.Integer] struct{ f T } - testFloat[T constraints.Float] struct{ f T } - testComplex[T constraints.Complex] struct{ f T } - testOrdered[T constraints.Ordered] struct{ f T } -) -`) - -func TestFailure(t *testing.T) { - testenv.MustHaveGoBuild(t) - gocmd := testenv.GoToolPath(t) - tmpdir := t.TempDir() - - if err := os.WriteFile(filepath.Join(tmpdir, "go.mod"), []byte("module constraintest"), 0666); err != nil { - t.Fatal(err) - } - - // Test for types that should not satisfy a constraint. - // For each pair of constraint and type, write a Go file - // var V constraint[type] - // For example, - // var V testSigned[uint] - // This should not compile, as testSigned (above) uses - // constraints.Signed, and uint does not satisfy that constraint. - // Therefore, the build of that code should fail. - for i, test := range []struct { - constraint, typ string - }{ - {"testSigned", "uint"}, - {"testUnsigned", "int"}, - {"testInteger", "float32"}, - {"testFloat", "int8"}, - {"testComplex", "float64"}, - {"testOrdered", "bool"}, - } { - i := i - test := test - t.Run(fmt.Sprintf("%s %d", test.constraint, i), func(t *testing.T) { - t.Parallel() - name := fmt.Sprintf("go%d.go", i) - f, err := os.Create(filepath.Join(tmpdir, name)) - if err != nil { - t.Fatal(err) - } - if _, err := f.Write(prolog); err != nil { - t.Fatal(err) - } - if _, err := fmt.Fprintf(f, "var V %s[%s]\n", test.constraint, test.typ); err != nil { - t.Fatal(err) - } - if err := f.Close(); err != nil { - t.Fatal(err) - } - cmd := exec.Command(gocmd, "build", name) - cmd.Dir = tmpdir - if out, err := cmd.CombinedOutput(); err == nil { - t.Error("build succeeded, but expected to fail") - } else if len(out) > 0 { - t.Logf("%s", out) - const want = "does not implement" - if !bytes.Contains(out, []byte(want)) { - t.Errorf("output does not include %q", want) - } - } else { - t.Error("no error output, expected something") - } - }) - } -} diff --git a/src/go/types/testdata/fixedbugs/issue47818.go2 b/src/go/types/testdata/fixedbugs/issue47818.go2 index 2631118baed94..546de1ce31345 100644 --- a/src/go/types/testdata/fixedbugs/issue47818.go2 +++ b/src/go/types/testdata/fixedbugs/issue47818.go2 @@ -8,8 +8,6 @@ package go1_17 -import "constraints" - type T[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ] struct{} // for init (and main, but we're not in package main) we should only get one error @@ -57,5 +55,3 @@ type ( _ = C1 _ = C2 ) - -type Ordered constraints /* ERROR using type constraint constraints\.Ordered requires go1\.18 or later */ .Ordered diff --git a/src/go/types/testdata/fixedbugs/issue49705.go2 b/src/go/types/testdata/fixedbugs/issue49705.go2 index 2b991b872211a..5b5fba2a1dc66 100644 --- a/src/go/types/testdata/fixedbugs/issue49705.go2 +++ b/src/go/types/testdata/fixedbugs/issue49705.go2 @@ -4,8 +4,11 @@ package p -import "constraints" +type Integer interface { + ~int | ~int8 | ~int16 | ~int32 | ~int64 | + ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr +} -func shl[I constraints.Integer](n int) I { +func shl[I Integer](n int) I { return 1 << n } diff --git a/test/typeparam/issue50121.dir/a.go b/test/typeparam/issue50121.dir/a.go index 9918fa38a6a6e..ca11b6b27a2d1 100644 --- a/test/typeparam/issue50121.dir/a.go +++ b/test/typeparam/issue50121.dir/a.go @@ -5,11 +5,15 @@ package a import ( - "constraints" "math/rand" ) -type Builder[T constraints.Integer] struct{} +type Integer interface { + ~int | ~int8 | ~int16 | ~int32 | ~int64 | + ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr +} + +type Builder[T Integer] struct{} func (r Builder[T]) New() T { return T(rand.Int()) diff --git a/test/typeparam/issue50121b.dir/a.go b/test/typeparam/issue50121b.dir/a.go index f2b706e0fd73e..4ddbb6ea84776 100644 --- a/test/typeparam/issue50121b.dir/a.go +++ b/test/typeparam/issue50121b.dir/a.go @@ -4,11 +4,12 @@ package a -import ( - "constraints" -) +type Integer interface { + ~int | ~int8 | ~int16 | ~int32 | ~int64 | + ~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr +} -type Builder[T constraints.Integer] struct{} +type Builder[T Integer] struct{} func (r Builder[T]) New() T { return T(42) diff --git a/test/typeparam/issue50193.go b/test/typeparam/issue50193.go index 8dc488244e296..76de588e7429e 100644 --- a/test/typeparam/issue50193.go +++ b/test/typeparam/issue50193.go @@ -7,17 +7,20 @@ package main import ( - "constraints" "fmt" ) -func zero[T constraints.Complex]() T { +type Complex interface { + ~complex64 | ~complex128 +} + +func zero[T Complex]() T { return T(0) } -func pi[T constraints.Complex]() T { +func pi[T Complex]() T { return T(3.14) } -func sqrtN1[T constraints.Complex]() T { +func sqrtN1[T Complex]() T { return T(-1i) }