cmd/compile, go/types: allow any anywhere (as a type)

Adjust types2 and go/types and some test cases. Because `any` is not treated specially anymore in constraint position we get additional errors in constraints if `any` is used before Go1.18 (in addition to the error that type parameter lists are not permitted before Go1.18). Fixes #33232. Change-Id: I85590c6094b07c3e494fef319e3a38d0217cf6f0 Reviewed-on: https://go-review.googlesource.com/c/go/+/351456 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>
golang · Sep 22, 2021 · 1e57748 · 1e57748
1 parent 7a03ca6
commit 1e57748
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Showing 14 changed files with 49 additions and 80 deletions.
diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go
@@ -625,13 +625,7 @@ func (check *Checker) collectTypeParams(dst **TypeParamList, list []*syntax.Fiel
 		// This also preserves the grouped output of type parameter lists
 		// when printing type strings.
 		if i == 0 || f.Type != list[i-1].Type {
-			// The predeclared identifier "any" is visible only as a type bound in a type parameter list.
-			// If we allow "any" for general use, this if-statement can be removed (issue #33232).
-			if name, _ := unparen(f.Type).(*syntax.Name); name != nil && name.Value == "any" && check.lookup("any") == universeAny {
-				bound = universeAny.Type()
-			} else {
-				bound = check.typ(f.Type)
-			}
+			bound = check.typ(f.Type)
 		}
 		tparams[i].bound = bound
 	}

diff --git a/src/cmd/compile/internal/types2/testdata/check/typeparams.go2 b/src/cmd/compile/internal/types2/testdata/check/typeparams.go2
@@ -6,11 +6,9 @@ package p
 
 // import "io" // for type assertion tests
 
-// The predeclared identifier "any" can only be used as a constraint
-// in a type parameter list.
-var _ any // ERROR cannot use any outside constraint position
-func _[_ any /* ok here */ , _ interface{any /* ERROR constraint */ }](any /* ERROR constraint */ ) {
-        var _ any /* ERROR constraint */
+var _ any // ok to use any anywhere
+func _[_ any, _ interface{any}](any) {
+        var _ any
 }
 
 func identity[T any](x T) T { return x }

diff --git a/src/cmd/compile/internal/types2/testdata/examples/constraints.go2 b/src/cmd/compile/internal/types2/testdata/examples/constraints.go2
@@ -33,20 +33,20 @@ type (
 	_ interface{int|~ /* ERROR overlapping terms ~int */ int }
 	_ interface{~int|~ /* ERROR overlapping terms ~int */ int }
 	_ interface{~int|MyInt /* ERROR overlapping terms p.MyInt and ~int */ }
-	_ interface{int|interface{}}
+	_ interface{int|any}
 	_ interface{int|~string|union}
 	_ interface{int|~string|interface{int}}
 	_ interface{union|union /* ERROR overlapping terms p.union and p.union */ }
 
 	// For now we do not permit interfaces with methods in unions.
-	_ interface{~ /* ERROR invalid use of ~ */ interface{}}
+	_ interface{~ /* ERROR invalid use of ~ */ any}
 	_ interface{int|interface /* ERROR cannot use .* in union */ { m() }}
 )
 
 type (
 	// Tilde is not permitted on defined types or interfaces.
 	foo int
-	bar interface{}
+	bar any
 	_ interface{foo}
 	_ interface{~ /* ERROR invalid use of ~ */ foo }
 	_ interface{~ /* ERROR invalid use of ~ */ bar }

diff --git a/src/cmd/compile/internal/types2/testdata/examples/types.go2 b/src/cmd/compile/internal/types2/testdata/examples/types.go2
@@ -114,7 +114,7 @@ type I1[T any] interface{
 }
 
 // There is no such thing as a variadic generic type.
-type _[T ... /* ERROR invalid use of ... */ interface{}] struct{}
+type _[T ... /* ERROR invalid use of ... */ any] struct{}
 
 // Generic interfaces may be embedded as one would expect.
 type I2 interface {
@@ -213,9 +213,9 @@ func Sum[T Adder[T]](list []T) T {
 }
 
 // Valid and invalid variations.
-type B0 interface {}
-type B1[_ any] interface{}
-type B2[_, _ any] interface{}
+type B0 any
+type B1[_ any] any
+type B2[_, _ any] any
 
 func _[T1 B0]() {}
 func _[T1 B1[T1]]() {}

diff --git a/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47818.go2 b/src/cmd/compile/internal/types2/testdata/fixedbugs/issue47818.go2
@@ -8,13 +8,13 @@
 
 package go1_17
 
-type T[P /* ERROR type parameters require go1\.18 or later */ any] struct{}
+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
-func init[P /* ERROR func init must have no type parameters */ any]()   {}
-func main[P /* ERROR type parameters require go1\.18 or later */ any]() {}
+func init[P /* ERROR func init must have no type parameters */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]()   {}
+func main[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]() {}
 
-func f[P /* ERROR type parameters require go1\.18 or later */ any](x P) {
+func f[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ](x P) {
 	var _ T[ /* ERROR type instantiation requires go1\.18 or later */ int]
 	var _ (T[ /* ERROR type instantiation requires go1\.18 or later */ int])
 	_ = T[ /* ERROR type instantiation requires go1\.18 or later */ int]{}

diff --git a/src/cmd/compile/internal/types2/typexpr.go b/src/cmd/compile/internal/types2/typexpr.go
@@ -38,16 +38,10 @@ func (check *Checker) ident(x *operand, e *syntax.Name, def *Named, wantType boo
 		}
 		return
 	case universeAny, universeComparable:
-		// complain if necessary
 		if !check.allowVersion(check.pkg, 1, 18) {
 			check.errorf(e, "undeclared name: %s (requires version go1.18 or later)", e.Value)
 			return // avoid follow-on errors
 		}
-		if obj == universeAny {
-			// If we allow "any" for general use, this if-statement can be removed (issue #33232).
-			check.softErrorf(e, "cannot use any outside constraint position")
-			// ok to continue
-		}
 	}
 	check.recordUse(e, obj)
 

diff --git a/src/go/types/decl.go b/src/go/types/decl.go
@@ -668,27 +668,18 @@ func (check *Checker) collectTypeParams(dst **TypeParamList, list *ast.FieldList
 	*dst = bindTParams(tparams)
 
 	index := 0
-	var bound Type
 	var bounds []Type
 	var posns []positioner // bound positions
 	for _, f := range list.List {
-		if f.Type == nil {
-			goto next
-		}
-		// The predeclared identifier "any" is visible only as a type bound in a type parameter list.
-		// If we allow "any" for general use, this if-statement can be removed (issue #33232).
-		if name, _ := unparen(f.Type).(*ast.Ident); name != nil && name.Name == "any" && check.lookup("any") == universeAny {
-			bound = universeAny.Type()
-		} else {
-			bound = check.typ(f.Type)
-		}
-		bounds = append(bounds, bound)
-		posns = append(posns, f.Type)
-		for i := range f.Names {
-			tparams[index+i].bound = bound
+		// TODO(rfindley) we should be able to rely on f.Type != nil at this point
+		if f.Type != nil {
+			bound := check.typ(f.Type)
+			bounds = append(bounds, bound)
+			posns = append(posns, f.Type)
+			for i := range f.Names {
+				tparams[index+i].bound = bound
+			}
 		}
-
-	next:
 		index += len(f.Names)
 	}
 

diff --git a/src/go/types/testdata/check/typeparams.go2 b/src/go/types/testdata/check/typeparams.go2
@@ -6,11 +6,9 @@ package p
 
 // import "io" // for type assertion tests
 
-// The predeclared identifier "any" can only be used as a constraint
-// in a type parameter list.
-var _ any // ERROR cannot use any outside constraint position
-func _[_ any /* ok here */ , _ interface{any /* ERROR constraint */ }](any /* ERROR constraint */ ) {
-        var _ any /* ERROR constraint */
+var _ any // ok to use any anywhere
+func _[_ any, _ interface{any}](any) {
+        var _ any
 }
 
 func identity[T any](x T) T { return x }

diff --git a/src/go/types/testdata/examples/constraints.go2 b/src/go/types/testdata/examples/constraints.go2
@@ -33,20 +33,20 @@ type (
 	_ interface{int|~ /* ERROR overlapping terms ~int */ int }
 	_ interface{~int|~ /* ERROR overlapping terms ~int */ int }
 	_ interface{~int|MyInt /* ERROR overlapping terms p.MyInt and ~int */ }
-	_ interface{int|interface{}}
+	_ interface{int|any}
 	_ interface{int|~string|union}
 	_ interface{int|~string|interface{int}}
 	_ interface{union|union /* ERROR overlapping terms p.union and p.union */ }
 
 	// For now we do not permit interfaces with methods in unions.
-	_ interface{~ /* ERROR invalid use of ~ */ interface{}}
+	_ interface{~ /* ERROR invalid use of ~ */ any}
 	_ interface{int|interface /* ERROR cannot use .* in union */ { m() }}
 )
 
 type (
 	// Tilde is not permitted on defined types or interfaces.
 	foo int
-	bar interface{}
+	bar any
 	_ interface{foo}
 	_ interface{~ /* ERROR invalid use of ~ */ foo }
 	_ interface{~ /* ERROR invalid use of ~ */ bar }

diff --git a/src/go/types/testdata/examples/types.go2 b/src/go/types/testdata/examples/types.go2
@@ -114,7 +114,7 @@ type I1[T any] interface{
 }
 
 // There is no such thing as a variadic generic type.
-type _[T ... /* ERROR invalid use of ... */ interface{}] struct{}
+type _[T ... /* ERROR invalid use of ... */ any] struct{}
 
 // Generic interfaces may be embedded as one would expect.
 type I2 interface {
@@ -219,9 +219,9 @@ func Sum[T Adder[T]](list []T) T {
 }
 
 // Valid and invalid variations.
-type B0 interface {}
-type B1[_ any] interface{}
-type B2[_, _ any] interface{}
+type B0 any
+type B1[_ any] any
+type B2[_, _ any] any
 
 func _[T1 B0]() {}
 func _[T1 B1[T1]]() {}

diff --git a/src/go/types/testdata/fixedbugs/issue47818.go2 b/src/go/types/testdata/fixedbugs/issue47818.go2
@@ -8,13 +8,13 @@
 
 package go1_17
 
-type T[P /* ERROR type parameters require go1\.18 or later */ any] struct{}
+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
-func init[P /* ERROR func init must have no type parameters */ any]()   {}
-func main[P /* ERROR type parameters require go1\.18 or later */ any]() {}
+func init[P /* ERROR func init must have no type parameters */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]()   {}
+func main[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ]() {}
 
-func f[P /* ERROR type parameters require go1\.18 or later */ any](x P) {
+func f[P /* ERROR type parameters require go1\.18 or later */ any /* ERROR undeclared name: any \(requires version go1\.18 or later\) */ ](x P) {
 	var _ T[ /* ERROR type instantiation requires go1\.18 or later */ int]
 	var _ (T[ /* ERROR type instantiation requires go1\.18 or later */ int])
 	_ = T[ /* ERROR type instantiation requires go1\.18 or later */ int]{}

diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go
@@ -36,16 +36,10 @@ func (check *Checker) ident(x *operand, e *ast.Ident, def *Named, wantType bool)
 		}
 		return
 	case universeAny, universeComparable:
-		// complain if necessary
 		if !check.allowVersion(check.pkg, 1, 18) {
 			check.errorf(e, _UndeclaredName, "undeclared name: %s (requires version go1.18 or later)", e.Name)
 			return // avoid follow-on errors
 		}
-		if obj == universeAny {
-			// If we allow "any" for general use, this if-statement can be removed (issue #33232).
-			check.softErrorf(e, _Todo, "cannot use any outside constraint position")
-			// ok to continue
-		}
 	}
 	check.recordUse(e, obj)
 

diff --git a/test/fixedbugs/issue14652.go b/test/fixedbugs/issue14652.go
@@ -1,9 +1,10 @@
-// errorcheck
+// compile
 
 // Copyright 2016 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
 
-var x any // ERROR "undefined: any|undefined type .*any.*|cannot use any outside constraint position"
+// any is now permitted instead of interface{}
+var x any
diff --git a/test/typeparam/tparam1.go b/test/typeparam/tparam1.go
@@ -8,11 +8,10 @@
 
 package tparam1
 
-// The predeclared identifier "any" is only visible as a constraint
-// in a type parameter list.
-var _ any     // ERROR "cannot use any outside constraint position"
-func _(_ any) // ERROR "cannot use any outside constraint position"
-type _[_ any /* ok here */] struct{}
+// The predeclared identifier "any" may be used in place of interface{}.
+var _ any
+func _(_ any)
+type _[_ any] struct{}
 
 const N = 10
 
@@ -24,16 +23,16 @@ type (
 	_[T1, T2 any, T3 any] struct{}
 )
 
-func _[T any]() {}
-func _[T, T any]() {} // ERROR "T redeclared"
+func _[T any]()             {}
+func _[T, T any]()          {} // ERROR "T redeclared"
 func _[T1, T2 any](x T1) T2 { panic(0) }
 
 // Type parameters are visible from opening [ to end of function.
 type C interface{}
 
-func _[T interface{}]() {}
-func _[T C]() {}
-func _[T struct{}]() {}// ERROR "not an interface"
+func _[T interface{}]()        {}
+func _[T C]()                  {}
+func _[T struct{}]()           {} // ERROR "not an interface"
 func _[T interface{ m() T }]() {}
 func _[T1 interface{ m() T2 }, T2 interface{ m() T1 }]() {
 	var _ T1