Requires -newparser=1.
For #17487.
For #16339.
Change-Id: I156fb0c0f8a97e8c72dbbfbd7fe821efee12b957
Reviewed-on: https://go-review.googlesource.com/31597
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
s.Def.Name.Pack.Used = true
}
+ // TODO(gri) This will also affect exported aliases.
+ // Need to fix this.
s.Def = nil
continue
}
p.importDecl(decl)
case *syntax.AliasDecl:
- yyerror("alias declarations not yet implemented")
+ p.aliasDecl(decl)
case *syntax.VarDecl:
l = append(l, p.varDecl(decl)...)
lastConstGroup = decl.Group
case *syntax.TypeDecl:
+ // TODO(gri) remove this notation - we're not going to use it after all
if decl.Alias {
- yyerror("alias declarations not yet implemented")
+ yyerror("type aliases using = not supported")
break
}
l = append(l, p.typeDecl(decl))
my.Block = 1 // at top level
}
+func (p *noder) aliasDecl(decl *syntax.AliasDecl) {
+ // Because alias declarations must refer to imported entities
+ // which are already set up, we can do all checks right here.
+ // We won't know anything about entities that have not been
+ // declared yet, but since they cannot have been imported, we
+ // know there's an error and we don't care about the details.
+
+ // The original entity must be denoted by a qualified identifier.
+ // (The parser doesn't make this restriction to be more error-
+ // tolerant.)
+ qident, ok := decl.Orig.(*syntax.SelectorExpr)
+ if !ok {
+ // TODO(gri) This prints a dot-imported object with qualification
+ // (confusing error). Fix this.
+ yyerror("invalid alias: %v is not a package-qualified identifier", p.expr(decl.Orig))
+ return
+ }
+
+ pkg := p.expr(qident.X)
+ if pkg.Op != OPACK {
+ yyerror("invalid alias: %v is not a package", pkg)
+ return
+ }
+ pkg.Used = true
+
+ orig := oldname(restrictlookup(qident.Sel.Value, pkg.Name.Pkg))
+
+ // An alias declaration must not refer to package unsafe.
+ if orig.Sym.Pkg == unsafepkg {
+ yyerror("invalid alias: %v refers to package unsafe (%v)", decl.Name.Value, orig)
+ return
+ }
+
+ // The aliased entity must be from a matching constant, type, variable,
+ // or function declaration, respectively.
+ var what string
+ switch decl.Tok {
+ case syntax.Const:
+ if orig.Op != OLITERAL {
+ what = "constant"
+ }
+ case syntax.Type:
+ if orig.Op != OTYPE {
+ what = "type"
+ }
+ case syntax.Var:
+ if orig.Op != ONAME || orig.Class != PEXTERN {
+ what = "variable"
+ }
+ case syntax.Func:
+ if orig.Op != ONAME || orig.Class != PFUNC {
+ what = "function"
+ }
+ default:
+ Fatalf("unexpected token: %s", decl.Tok)
+ }
+ if what != "" {
+ yyerror("invalid alias: %v is not a %s", orig, what)
+ return
+ }
+
+ // don't declare blank aliases
+ if decl.Name.Value == "_" {
+ return
+ }
+
+ // declare alias
+ // (this is similar to handling dot imports)
+ asym := p.name(decl.Name)
+ if asym.Def != nil {
+ redeclare(asym, "in alias declaration")
+ return
+ }
+ asym.Def = orig
+ asym.Block = block
+ asym.Lastlineno = lineno
+
+ if exportname(asym.Name) {
+ yyerror("cannot export alias %v: not yet implemented", asym)
+ // TODO(gri) newname(asym) is only needed to satisfy exportsym
+ // (and indirectly, exportlist). We should be able to just
+ // collect the Syms, eventually.
+ // exportsym(newname(asym))
+ }
+}
+
func (p *noder) varDecl(decl *syntax.VarDecl) []*Node {
names := p.declNames(decl.NameList)
}
testTestDir(t, filepath.Join(runtime.GOROOT(), "test"),
+ "alias2.go", // excluded until we can handle alias declarations
"cmplxdivide.go", // also needs file cmplxdivide1.go - ignore
"sigchld.go", // don't work on Windows; testTestDir should consult build tags
)
--- /dev/null
+// errorcheck -newparser=1
+
+// 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.
+
+// Test basic restrictions on alias declarations.
+
+package p
+
+import (
+ "fmt" // use at most once (to test "imported but not used" error)
+ "go/build"
+ . "go/build"
+ "io"
+ "math"
+ "unsafe"
+)
+
+// helper
+var before struct {
+ f
+}
+
+// aliases must refer to package-qualified identifiers
+// TODO(gri) should only see one error for declaration below - fix this
+const _ => 0 // ERROR "unexpected literal 0|_ is not a package-qualified identifier"
+
+type _ => _ // ERROR "_ is not a package-qualified identifier"
+type t => _ // ERROR "_ is not a package-qualified identifier"
+
+const _ => iota // ERROR "iota is not a package-qualified identifier"
+type _ => int // ERROR "int is not a package-qualified identifier"
+
+const c => iota // ERROR "iota is not a package-qualified identifier"
+type t => int // ERROR "int is not a package-qualified identifier"
+
+// dot-imported identifiers are not qualified identifiers
+// TODO(gri) fix error printing - should not print a qualified identifier...
+var _ => Default // ERROR "build\.Default is not a package-qualified identifier"
+
+// qualified identifiers must start with a package
+var _ => before.f // ERROR "before is not a package"
+func _ => before.f // ERROR "before is not a package"
+var _ => after.m // ERROR "after is not a package"
+func _ => after.m // ERROR "after is not a package"
+
+var v => before.f // ERROR "before is not a package"
+func f => before.f // ERROR "before is not a package"
+var v => after.m // ERROR "after is not a package"
+func f => after.m // ERROR "after is not a package"
+
+// TODO(gri) fix error printing - should not print a qualified identifier...
+var _ => Default.ARCH // ERROR "build.Default is not a package"
+
+// aliases may not refer to package unsafe
+type ptr => unsafe.Pointer // ERROR "ptr refers to package unsafe"
+func size => unsafe.Sizeof // ERROR "size refers to package unsafe"
+
+// aliases must refer to entities of the same kind
+const _ => math.Pi
+const pi => math.Pi
+const pi1 => math.Sin // ERROR "math.Sin is not a constant"
+
+type _ => io.Writer
+type writer => io.Writer
+type writer1 => math.Sin // ERROR "math.Sin is not a type"
+
+var _ => build.Default
+var def => build.Default
+var def1 => build.Import // ERROR "build.Import is not a variable"
+
+func _ => math.Sin
+func sin => math.Sin
+func sin1 => math.Pi // ERROR "math.Pi is not a function"
+
+// alias reference to a package marks package as used
+func _ => fmt.Println
+
+// TODO(gri) aliased cannot be exported yet - fix this
+const Pi => math.Pi // ERROR "cannot export alias Pi"
+type Writer => io.Writer // ERROR "cannot export alias Writer"
+var Def => build.Default // ERROR "cannot export alias Def"
+func Sin => math.Sin // ERROR "cannot export alias Sin"
+
+// type aliases denote identical types
+type myPackage => build.Package
+
+var pkg myPackage
+var _ build.Package = pkg // valid assignment
+var _ *build.Package = &pkg // valid assignment
+
+// helper
+type after struct{}
+
+func (after) m() {}