-// UNREVIEWED
// Copyright 2013 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.
"cmd/compile/internal/syntax"
"fmt"
"go/constant"
+ . "internal/types/errors"
"sort"
"strconv"
"strings"
// A declInfo describes a package-level const, type, var, or func declaration.
type declInfo struct {
- file *Scope // scope of file containing this declaration
- lhs []*Var // lhs of n:1 variable declarations, or nil
- vtyp syntax.Expr // type, or nil (for const and var declarations only)
- init syntax.Expr // init/orig expression, or nil (for const and var declarations only)
- tdecl *syntax.TypeDecl // type declaration, or nil
- fdecl *syntax.FuncDecl // func declaration, or nil
+ file *Scope // scope of file containing this declaration
+ lhs []*Var // lhs of n:1 variable declarations, or nil
+ vtyp syntax.Expr // type, or nil (for const and var declarations only)
+ init syntax.Expr // init/orig expression, or nil (for const and var declarations only)
+ inherited bool // if set, the init expression is inherited from a previous constant declaration
+ tdecl *syntax.TypeDecl // type declaration, or nil
+ fdecl *syntax.FuncDecl // func declaration, or nil
// The deps field tracks initialization expression dependencies.
deps map[Object]bool // lazily initialized
l := len(names)
r := len(inits)
+ const code = WrongAssignCount
switch {
case l < r:
n := inits[l]
if inherited {
- check.errorf(pos, "extra init expr at %s", n.Pos())
+ check.errorf(pos, code, "extra init expr at %s", n.Pos())
} else {
- check.errorf(n, "extra init expr %s", n)
+ check.errorf(n, code, "extra init expr %s", n)
}
case l > r && (constDecl || r != 1): // if r == 1 it may be a multi-valued function and we can't say anything yet
n := names[r]
- check.errorf(n, "missing init expr for %s", n.Value)
+ check.errorf(n, code, "missing init expr for %s", n.Value)
}
}
// spec: "A package-scope or file-scope identifier with name init
// may only be declared to be a function with this (func()) signature."
if ident.Value == "init" {
- check.errorf(ident, "cannot declare init - must be func")
+ check.error(ident, InvalidInitDecl, "cannot declare init - must be func")
return
}
// spec: "The main package must have package name main and declare
// a function main that takes no arguments and returns no value."
if ident.Value == "main" && check.pkg.name == "main" {
- check.errorf(ident, "cannot declare main - must be func")
+ check.error(ident, InvalidMainDecl, "cannot declare main - must be func")
return
}
imp = nil // create fake package below
}
if err != nil {
- check.errorf(pos, "could not import %s (%s)", path, err)
+ check.errorf(pos, BrokenImport, "could not import %s (%s)", path, err)
if imp == nil {
// create a new fake package
// come up with a sensible package name (heuristic)
// package should be complete or marked fake, but be cautious
if imp.complete || imp.fake {
check.impMap[key] = imp
- check.pkgCnt[imp.name]++
+ // Once we've formatted an error message, keep the pkgPathMap
+ // up-to-date on subsequent imports. It is used for package
+ // qualification in error messages.
+ if check.pkgPathMap != nil {
+ check.markImports(imp)
+ }
return imp
}
// but there is no corresponding package object.
check.recordDef(file.PkgName, nil)
- fileScope := NewScope(check.pkg.scope, startPos(file), endPos(file), check.filename(fileNo))
+ fileScope := NewScope(pkg.scope, syntax.StartPos(file), syntax.EndPos(file), check.filename(fileNo))
fileScopes = append(fileScopes, fileScope)
check.recordScope(file, fileScope)
switch s := decl.(type) {
case *syntax.ImportDecl:
// import package
+ if s.Path == nil || s.Path.Bad {
+ continue // error reported during parsing
+ }
path, err := validatedImportPath(s.Path.Value)
if err != nil {
- check.errorf(s.Path, "invalid import path (%s)", err)
+ check.errorf(s.Path, BadImportPath, "invalid import path (%s)", err)
continue
}
continue
}
- // add package to list of explicit imports
- // (this functionality is provided as a convenience
- // for clients; it is not needed for type-checking)
- if !pkgImports[imp] {
- pkgImports[imp] = true
- pkg.imports = append(pkg.imports, imp)
- }
-
// local name overrides imported package name
name := imp.name
if s.LocalPkgName != nil {
name = s.LocalPkgName.Value
if path == "C" {
- // match cmd/compile (not prescribed by spec)
- check.errorf(s.LocalPkgName, `cannot rename import "C"`)
- continue
- }
- if name == "init" {
- check.errorf(s.LocalPkgName, "cannot declare init - must be func")
+ // match 1.17 cmd/compile (not prescribed by spec)
+ check.error(s.LocalPkgName, ImportCRenamed, `cannot rename import "C"`)
continue
}
}
- obj := NewPkgName(s.Pos(), pkg, name, imp)
+ if name == "init" {
+ check.error(s, InvalidInitDecl, "cannot import package as init - init must be a func")
+ continue
+ }
+
+ // add package to list of explicit imports
+ // (this functionality is provided as a convenience
+ // for clients; it is not needed for type-checking)
+ if !pkgImports[imp] {
+ pkgImports[imp] = true
+ pkg.imports = append(pkg.imports, imp)
+ }
+
+ pkgName := NewPkgName(s.Pos(), pkg, name, imp)
if s.LocalPkgName != nil {
// in a dot-import, the dot represents the package
- check.recordDef(s.LocalPkgName, obj)
+ check.recordDef(s.LocalPkgName, pkgName)
} else {
- check.recordImplicit(s, obj)
+ check.recordImplicit(s, pkgName)
}
- if path == "C" {
- // match cmd/compile (not prescribed by spec)
- obj.used = true
+ if imp.fake {
+ // match 1.17 cmd/compile (not prescribed by spec)
+ pkgName.used = true
}
// add import to file scope
+ check.imports = append(check.imports, pkgName)
if name == "." {
+ // dot-import
+ if check.dotImportMap == nil {
+ check.dotImportMap = make(map[dotImportKey]*PkgName)
+ }
// merge imported scope with file scope
- for _, obj := range imp.scope.elems {
+ for name, obj := range imp.scope.elems {
+ // Note: Avoid eager resolve(name, obj) here, so we only
+ // resolve dot-imported objects as needed.
+
// A package scope may contain non-exported objects,
// do not import them!
- if obj.Exported() {
+ if isExported(name) {
// declare dot-imported object
// (Do not use check.declare because it modifies the object
// via Object.setScopePos, which leads to a race condition;
// the object may be imported into more than one file scope
- // concurrently. See issue #32154.)
- if alt := fileScope.Insert(obj); alt != nil {
- check.errorf(s.LocalPkgName, "%s redeclared in this block", obj.Name())
- check.reportAltDecl(alt)
+ // concurrently. See go.dev/issue/32154.)
+ if alt := fileScope.Lookup(name); alt != nil {
+ var err error_
+ err.code = DuplicateDecl
+ err.errorf(s.LocalPkgName, "%s redeclared in this block", alt.Name())
+ err.recordAltDecl(alt)
+ check.report(&err)
+ } else {
+ fileScope.insert(name, obj)
+ check.dotImportMap[dotImportKey{fileScope, name}] = pkgName
}
}
}
- // add position to set of dot-import positions for this file
- // (this is only needed for "imported but not used" errors)
- check.addUnusedDotImport(fileScope, imp, s.Pos())
} else {
// declare imported package object in file scope
// (no need to provide s.LocalPkgName since we called check.recordDef earlier)
- check.declare(fileScope, nil, obj, nopos)
+ check.declare(fileScope, nil, pkgName, nopos)
}
case *syntax.ConstDecl:
// iota is the index of the current constDecl within the group
- if first < 0 || file.DeclList[index-1].(*syntax.ConstDecl).Group != s.Group {
+ if first < 0 || s.Group == nil || file.DeclList[index-1].(*syntax.ConstDecl).Group != s.Group {
first = index
last = nil
}
}
// declare all constants
- values := unpackExpr(last.Values)
+ values := syntax.UnpackListExpr(last.Values)
for i, name := range s.NameList {
obj := NewConst(name.Pos(), pkg, name.Value, nil, iota)
init = values[i]
}
- d := &declInfo{file: fileScope, vtyp: last.Type, init: init}
+ d := &declInfo{file: fileScope, vtyp: last.Type, init: init, inherited: inherited}
check.declarePkgObj(name, obj, d)
}
}
// declare all variables
- values := unpackExpr(s.Values)
+ values := syntax.UnpackListExpr(s.Values)
for i, name := range s.NameList {
obj := NewVar(name.Pos(), pkg, name.Value, nil)
lhs[i] = obj
}
case *syntax.TypeDecl:
+ _ = len(s.TParamList) != 0 && check.verifyVersionf(s.TParamList[0], go1_18, "type parameter")
obj := NewTypeName(s.Name.Pos(), pkg, s.Name.Value, nil)
check.declarePkgObj(s.Name, obj, &declInfo{file: fileScope, tdecl: s})
case *syntax.FuncDecl:
- d := s // TODO(gri) get rid of this
- name := d.Name.Value
- obj := NewFunc(d.Name.Pos(), pkg, name, nil)
- if d.Recv == nil {
+ name := s.Name.Value
+ obj := NewFunc(s.Name.Pos(), pkg, name, nil)
+ hasTParamError := false // avoid duplicate type parameter errors
+ if s.Recv == nil {
// regular function
- if name == "init" {
- if d.TParamList != nil {
- //check.softErrorf(d.TParamList.Pos(), "func init must have no type parameters")
- check.softErrorf(d.Name, "func init must have no type parameters")
+ if name == "init" || name == "main" && pkg.name == "main" {
+ code := InvalidInitDecl
+ if name == "main" {
+ code = InvalidMainDecl
}
- if t := d.Type; len(t.ParamList) != 0 || len(t.ResultList) != 0 {
- check.softErrorf(d, "func init must have no arguments and no return values")
+ if len(s.TParamList) != 0 {
+ check.softErrorf(s.TParamList[0], code, "func %s must have no type parameters", name)
+ hasTParamError = true
}
- // don't declare init functions in the package scope - they are invisible
+ if t := s.Type; len(t.ParamList) != 0 || len(t.ResultList) != 0 {
+ check.softErrorf(s.Name, code, "func %s must have no arguments and no return values", name)
+ }
+ }
+ // don't declare init functions in the package scope - they are invisible
+ if name == "init" {
obj.parent = pkg.scope
- check.recordDef(d.Name, obj)
+ check.recordDef(s.Name, obj)
// init functions must have a body
- if d.Body == nil {
+ if s.Body == nil {
// TODO(gri) make this error message consistent with the others above
- check.softErrorf(obj.pos, "missing function body")
+ check.softErrorf(obj.pos, MissingInitBody, "missing function body")
}
} else {
- check.declare(pkg.scope, d.Name, obj, nopos)
+ check.declare(pkg.scope, s.Name, obj, nopos)
}
} else {
// method
// d.Recv != nil
- if !methodTypeParamsOk && len(d.TParamList) != 0 {
- //check.invalidASTf(d.TParamList.Pos(), "method must have no type parameters")
- check.invalidASTf(d, "method must have no type parameters")
- }
- ptr, recv, _ := check.unpackRecv(d.Recv.Type, false)
- // (Methods with invalid receiver cannot be associated to a type, and
+ ptr, recv, _ := check.unpackRecv(s.Recv.Type, false)
+ // Methods with invalid receiver cannot be associated to a type, and
// methods with blank _ names are never found; no need to collect any
- // of them. They will still be type-checked with all the other functions.)
+ // of them. They will still be type-checked with all the other functions.
if recv != nil && name != "_" {
methods = append(methods, methodInfo{obj, ptr, recv})
}
- check.recordDef(d.Name, obj)
+ check.recordDef(s.Name, obj)
}
- info := &declInfo{file: fileScope, fdecl: d}
+ _ = len(s.TParamList) != 0 && !hasTParamError && check.verifyVersionf(s.TParamList[0], go1_18, "type parameter")
+ info := &declInfo{file: fileScope, fdecl: s}
// Methods are not package-level objects but we still track them in the
// object map so that we can handle them like regular functions (if the
// receiver is invalid); also we need their fdecl info when associating
obj.setOrder(uint32(len(check.objMap)))
default:
- check.invalidASTf(s, "unknown syntax.Decl node %T", s)
+ check.errorf(s, InvalidSyntaxTree, "unknown syntax.Decl node %T", s)
}
}
}
// verify that objects in package and file scopes have different names
for _, scope := range fileScopes {
- for _, obj := range scope.elems {
- if alt := pkg.scope.Lookup(obj.Name()); alt != nil {
+ for name, obj := range scope.elems {
+ if alt := pkg.scope.Lookup(name); alt != nil {
+ obj = resolve(name, obj)
+ var err error_
+ err.code = DuplicateDecl
if pkg, ok := obj.(*PkgName); ok {
- check.errorf(alt, "%s already declared through import of %s", alt.Name(), pkg.Imported())
- check.reportAltDecl(pkg)
+ err.errorf(alt, "%s already declared through import of %s", alt.Name(), pkg.Imported())
+ err.recordAltDecl(pkg)
} else {
- check.errorf(alt, "%s already declared through dot-import of %s", alt.Name(), obj.Pkg())
- // TODO(gri) dot-imported objects don't have a position; reportAltDecl won't print anything
- check.reportAltDecl(obj)
+ err.errorf(alt, "%s already declared through dot-import of %s", alt.Name(), obj.Pkg())
+ // TODO(gri) dot-imported objects don't have a position; recordAltDecl won't print anything
+ err.recordAltDecl(obj)
}
+ check.report(&err)
}
}
}
for i := range methods {
m := &methods[i]
// Determine the receiver base type and associate m with it.
- ptr, base := check.resolveBaseTypeName(m.ptr, m.recv)
+ ptr, base := check.resolveBaseTypeName(m.ptr, m.recv, fileScopes)
if base != nil {
- m.obj.hasPtrRecv = ptr
+ m.obj.hasPtrRecv_ = ptr
check.methods[base] = append(check.methods[base], m.obj)
}
}
case *syntax.ParenExpr:
rtyp = t.X
// case *ast.StarExpr:
+ // ptr = true
// rtyp = t.X
case *syntax.Operation:
if t.Op != syntax.Mul || t.Y != nil {
break
}
+ ptr = true
rtyp = t.X
default:
break L
if ptyp, _ := rtyp.(*syntax.IndexExpr); ptyp != nil {
rtyp = ptyp.X
if unpackParams {
- for _, arg := range unpackExpr(ptyp.Index) {
+ for _, arg := range syntax.UnpackListExpr(ptyp.Index) {
var par *syntax.Name
switch arg := arg.(type) {
case *syntax.Name:
case *syntax.BadExpr:
// ignore - error already reported by parser
case nil:
- check.invalidASTf(ptyp, "parameterized receiver contains nil parameters")
+ check.error(ptyp, InvalidSyntaxTree, "parameterized receiver contains nil parameters")
default:
- check.errorf(arg, "receiver type parameter %s must be an identifier", arg)
+ check.errorf(arg, BadDecl, "receiver type parameter %s must be an identifier", arg)
}
if par == nil {
- par = newName(arg.Pos(), "_")
+ par = syntax.NewName(arg.Pos(), "_")
}
tparams = append(tparams, par)
}
// there was a pointer indirection to get to it. The base type name must be declared
// in package scope, and there can be at most one pointer indirection. If no such type
// name exists, the returned base is nil.
-func (check *Checker) resolveBaseTypeName(seenPtr bool, typ syntax.Expr) (ptr bool, base *TypeName) {
+func (check *Checker) resolveBaseTypeName(seenPtr bool, typ syntax.Expr, fileScopes []*Scope) (ptr bool, base *TypeName) {
// Algorithm: Starting from a type expression, which may be a name,
// we follow that type through alias declarations until we reach a
// non-alias type name. If we encounter anything but pointer types or
ptr = seenPtr
var seen map[*TypeName]bool
for {
- typ = unparen(typ)
-
// check if we have a pointer type
// if pexpr, _ := typ.(*ast.StarExpr); pexpr != nil {
if pexpr, _ := typ.(*syntax.Operation); pexpr != nil && pexpr.Op == syntax.Mul && pexpr.Y == nil {
return false, nil
}
ptr = true
- typ = unparen(pexpr.X) // continue with pointer base type
+ typ = syntax.Unparen(pexpr.X) // continue with pointer base type
}
- // typ must be a name
- name, _ := typ.(*syntax.Name)
- if name == nil {
+ // typ must be a name, or a C.name cgo selector.
+ var name string
+ switch typ := typ.(type) {
+ case *syntax.Name:
+ name = typ.Value
+ case *syntax.SelectorExpr:
+ // C.struct_foo is a valid type name for packages using cgo.
+ //
+ // Detect this case, and adjust name so that the correct TypeName is
+ // resolved below.
+ if ident, _ := typ.X.(*syntax.Name); ident != nil && ident.Value == "C" {
+ // Check whether "C" actually resolves to an import of "C", by looking
+ // in the appropriate file scope.
+ var obj Object
+ for _, scope := range fileScopes {
+ if scope.Contains(ident.Pos()) {
+ obj = scope.Lookup(ident.Value)
+ }
+ }
+ // If Config.go115UsesCgo is set, the typechecker will resolve Cgo
+ // selectors to their cgo name. We must do the same here.
+ if pname, _ := obj.(*PkgName); pname != nil {
+ if pname.imported.cgo { // only set if Config.go115UsesCgo is set
+ name = "_Ctype_" + typ.Sel.Value
+ }
+ }
+ }
+ if name == "" {
+ return false, nil
+ }
+ default:
return false, nil
}
// name must denote an object found in the current package scope
// (note that dot-imported objects are not in the package scope!)
- obj := check.pkg.scope.Lookup(name.Value)
+ obj := check.pkg.scope.Lookup(name)
if obj == nil {
return false, nil
}
}
}
- // We process non-alias declarations first, in order to avoid situations where
- // the type of an alias declaration is needed before it is available. In general
- // this is still not enough, as it is possible to create sufficiently convoluted
- // recursive type definitions that will cause a type alias to be needed before it
- // is available (see issue #25838 for examples).
- // As an aside, the cmd/compiler suffers from the same problem (#25838).
- var aliasList []*TypeName
- // phase 1
- for _, obj := range objList {
- // If we have a type alias, collect it for the 2nd phase.
- if tname, _ := obj.(*TypeName); tname != nil && check.objMap[tname].tdecl.Alias {
- aliasList = append(aliasList, tname)
- continue
+ if check.conf._EnableAlias {
+ // With _Alias nodes we can process declarations in any order.
+ for _, obj := range objList {
+ check.objDecl(obj, nil)
+ }
+ } else {
+ // Without _Alias nodes, we process non-alias type declarations first, followed by
+ // alias declarations, and then everything else. This appears to avoid most situations
+ // where the type of an alias is needed before it is available.
+ // There may still be cases where this is not good enough (see also go.dev/issue/25838).
+ // In those cases Checker.ident will report an error ("invalid use of type alias").
+ var aliasList []*TypeName
+ var othersList []Object // everything that's not a type
+ // phase 1: non-alias type declarations
+ for _, obj := range objList {
+ if tname, _ := obj.(*TypeName); tname != nil {
+ if check.objMap[tname].tdecl.Alias {
+ aliasList = append(aliasList, tname)
+ } else {
+ check.objDecl(obj, nil)
+ }
+ } else {
+ othersList = append(othersList, obj)
+ }
+ }
+ // phase 2: alias type declarations
+ for _, obj := range aliasList {
+ check.objDecl(obj, nil)
+ }
+ // phase 3: all other declarations
+ for _, obj := range othersList {
+ check.objDecl(obj, nil)
}
-
- check.objDecl(obj, nil)
- }
- // phase 2
- for _, obj := range aliasList {
- check.objDecl(obj, nil)
}
// At this point we may have a non-empty check.methods map; this means that not all
// unusedImports checks for unused imports.
func (check *Checker) unusedImports() {
- // if function bodies are not checked, packages' uses are likely missing - don't check
+ // If function bodies are not checked, packages' uses are likely missing - don't check.
if check.conf.IgnoreFuncBodies {
return
}
// any of its exported identifiers. To import a package solely for its side-effects
// (initialization), use the blank identifier as explicit package name."
- // check use of regular imported packages
- for _, scope := range check.pkg.scope.children /* file scopes */ {
- for _, obj := range scope.elems {
- if obj, ok := obj.(*PkgName); ok {
- // Unused "blank imports" are automatically ignored
- // since _ identifiers are not entered into scopes.
- if !obj.used {
- path := obj.imported.path
- base := pkgName(path)
- if obj.name == base {
- check.softErrorf(obj.pos, "%q imported but not used", path)
- } else {
- check.softErrorf(obj.pos, "%q imported but not used as %s", path, obj.name)
- }
- }
- }
- }
- }
-
- // check use of dot-imported packages
- for _, unusedDotImports := range check.unusedDotImports {
- for pkg, pos := range unusedDotImports {
- check.softErrorf(pos, "%q imported but not used", pkg.path)
+ for _, obj := range check.imports {
+ if !obj.used && obj.name != "_" {
+ check.errorUnusedPkg(obj)
}
}
}
-// pkgName returns the package name (last element) of an import path.
-func pkgName(path string) string {
- if i := strings.LastIndex(path, "/"); i >= 0 {
- path = path[i+1:]
+func (check *Checker) errorUnusedPkg(obj *PkgName) {
+ // If the package was imported with a name other than the final
+ // import path element, show it explicitly in the error message.
+ // Note that this handles both renamed imports and imports of
+ // packages containing unconventional package declarations.
+ // Note that this uses / always, even on Windows, because Go import
+ // paths always use forward slashes.
+ path := obj.imported.path
+ elem := path
+ if i := strings.LastIndex(elem, "/"); i >= 0 {
+ elem = elem[i+1:]
+ }
+ if obj.name == "" || obj.name == "." || obj.name == elem {
+ check.softErrorf(obj, UnusedImport, "%q imported and not used", path)
+ } else {
+ check.softErrorf(obj, UnusedImport, "%q imported as %s and not used", path, obj.name)
}
- return path
}
// dir makes a good-faith attempt to return the directory