// lookup returns the address of the named variable identified by obj
// that is local to function f or one of its enclosing functions.
// If escaping, the reference comes from a potentially escaping pointer
// expression and the referent must be heap-allocated.
//
func (f *Function) lookup(obj types.Object, escaping bool) Value {
if v, ok := f.objects[obj]; ok {
if alloc, ok := v.(*Alloc); ok && escaping {
alloc.Heap = true
}
return v // function-local var (address)
}
// Definition must be in an enclosing function;
// plumb it through intervening closures.
if f.Enclosing == nil {
panic("no Value for type.Object " + obj.Name())
}
outer := f.Enclosing.lookup(obj, true) // escaping
v := &Capture{
name: obj.Name(),
typ: outer.Type(),
pos: outer.Pos(),
outer: outer,
parent: f,
}
f.objects[obj] = v
f.FreeVars = append(f.FreeVars, v)
return v
}
func formatMember(obj types.Object, maxname int) string {
var buf bytes.Buffer
fmt.Fprintf(&buf, "%-5s %-*s", tokenOf(obj), maxname, obj.Name())
switch obj := obj.(type) {
case *types.Const:
fmt.Fprintf(&buf, " %s = %s", types.TypeString(obj.Pkg(), obj.Type()), obj.Val().String())
case *types.Func:
fmt.Fprintf(&buf, " %s", types.TypeString(obj.Pkg(), obj.Type()))
case *types.TypeName:
// Abbreviate long aggregate type names.
var abbrev string
switch t := obj.Type().Underlying().(type) {
case *types.Interface:
if t.NumMethods() > 1 {
abbrev = "interface{...}"
}
case *types.Struct:
if t.NumFields() > 1 {
abbrev = "struct{...}"
}
}
if abbrev == "" {
fmt.Fprintf(&buf, " %s", types.TypeString(obj.Pkg(), obj.Type().Underlying()))
} else {
fmt.Fprintf(&buf, " %s", abbrev)
}
case *types.Var:
fmt.Fprintf(&buf, " %s", types.TypeString(obj.Pkg(), obj.Type()))
}
return buf.String()
}
func (c *funcContext) objectName(o types.Object) string {
if o.Pkg() != c.p.pkg || o.Parent() == c.p.pkg.Scope() {
c.p.dependencies[o] = true
}
if o.Pkg() != c.p.pkg {
pkgVar, found := c.p.pkgVars[o.Pkg().Path()]
if !found {
pkgVar = fmt.Sprintf(`go$packages["%s"]`, o.Pkg().Path())
}
return pkgVar + "." + o.Name()
}
name, found := c.p.objectVars[o]
if !found {
name = c.newVariable(o.Name())
c.p.objectVars[o] = name
}
switch o.(type) {
case *types.Var, *types.Const:
if o.Exported() && o.Parent() == c.p.pkg.Scope() {
return "go$pkg." + name
}
}
return name
}
// isPackageLevel reports whether obj is a package-level object.
func isPackageLevel(obj types.Object) bool {
// TODO(adonovan): fix go/types bug:
// obj.Parent().Parent() == obj.Pkg().Scope()
// doesn't work because obj.Parent() gets mutated during
// dot-imports.
return obj.Pkg().Scope().Lookup(obj.Name()) == obj
}
// memberFromObject populates package pkg with a member for the
// typechecker object obj.
//
// For objects from Go source code, syntax is the associated syntax
// tree (for funcs and vars only); it will be used during the build
// phase.
//
func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
name := obj.Name()
switch obj := obj.(type) {
case *types.TypeName:
pkg.Members[name] = &Type{object: obj}
case *types.Const:
c := &NamedConst{
object: obj,
Value: NewConst(obj.Val(), obj.Type()),
}
pkg.values[obj] = c.Value
pkg.Members[name] = c
case *types.Var:
spec, _ := syntax.(*ast.ValueSpec)
g := &Global{
Pkg: pkg,
name: name,
object: obj,
typ: types.NewPointer(obj.Type()), // address
pos: obj.Pos(),
spec: spec,
}
pkg.values[obj] = g
pkg.Members[name] = g
case *types.Func:
var fs *funcSyntax
synthetic := "loaded from gc object file"
if decl, ok := syntax.(*ast.FuncDecl); ok {
synthetic = ""
fs = &funcSyntax{
functype: decl.Type,
recvField: decl.Recv,
body: decl.Body,
}
}
fn := &Function{
name: name,
object: obj,
Signature: obj.Type().(*types.Signature),
Synthetic: synthetic,
pos: obj.Pos(), // (iff syntax)
Pkg: pkg,
Prog: pkg.Prog,
syntax: fs,
}
pkg.values[obj] = fn
if fn.Signature.Recv() == nil {
pkg.Members[name] = fn // package-level function
}
default: // (incl. *types.Package)
panic("unexpected Object type: " + obj.String())
}
}
func (f *Function) addParamObj(obj types.Object) *Parameter {
name := obj.Name()
if name == "" {
name = fmt.Sprintf("arg%d", len(f.Params))
}
param := f.addParam(name, obj.Type(), obj.Pos())
param.object = obj
return param
}
// addSpilledParam declares a parameter that is pre-spilled to the
// stack; the function body will load/store the spilled location.
// Subsequent lifting will eliminate spills where possible.
//
func (f *Function) addSpilledParam(obj types.Object) {
param := f.addParamObj(obj)
spill := &Alloc{Comment: obj.Name()}
spill.setType(types.NewPointer(obj.Type()))
spill.setPos(obj.Pos())
f.objects[obj] = spill
f.Locals = append(f.Locals, spill)
f.emit(spill)
f.emit(&Store{Addr: spill, Val: param})
}
func (r *resolver) defineObject(b *Block, name string, obj types.Object) {
if obj.Name() == "_" {
return
}
i := len(b.bindings)
b.bindings = append(b.bindings, obj)
b.index[name] = i
if trace {
logf("def %s = %s in %s\n", name, types.ObjectString(r.pkg, obj), b)
}
r.result.Defs[obj] = b
}
func (p *printer) printObj(obj types.Object) {
p.printf("%s", obj.Name())
// don't write untyped types (for constants)
if typ := obj.Type(); typed(typ) {
p.print(" ")
p.writeType(p.pkg, typ)
}
// write constant value
if obj, ok := obj.(*types.Const); ok {
p.printf(" = %s", obj.Val())
}
}
// memberFromObject populates package pkg with a member for the
// typechecker object obj.
//
// For objects from Go source code, syntax is the associated syntax
// tree (for funcs and vars only); it will be used during the build
// phase.
//
func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
name := obj.Name()
switch obj := obj.(type) {
case *types.TypeName:
pkg.values[obj] = nil // for needMethods
pkg.Members[name] = &Type{
object: obj,
pkg: pkg,
}
case *types.Const:
c := &NamedConst{
object: obj,
Value: NewConst(obj.Val(), obj.Type()),
pkg: pkg,
}
pkg.values[obj] = c.Value
pkg.Members[name] = c
case *types.Var:
g := &Global{
Pkg: pkg,
name: name,
object: obj,
typ: types.NewPointer(obj.Type()), // address
pos: obj.Pos(),
}
pkg.values[obj] = g
pkg.Members[name] = g
case *types.Func:
fn := &Function{
name: name,
object: obj,
Signature: obj.Type().(*types.Signature),
syntax: syntax,
pos: obj.Pos(), // (iff syntax)
Pkg: pkg,
Prog: pkg.Prog,
}
if syntax == nil {
fn.Synthetic = "loaded from gc object file"
}
pkg.values[obj] = fn
if fn.Signature.Recv() == nil {
pkg.Members[name] = fn // package-level function
}
default: // (incl. *types.Package)
panic("unexpected Object type: " + obj.String())
}
}
// addSpilledParam declares a parameter that is pre-spilled to the
// stack; the function body will load/store the spilled location.
// Subsequent lifting will eliminate spills where possible.
//
func (f *Function) addSpilledParam(obj types.Object) {
name := obj.Name()
param := f.addParam(name, obj.Type())
spill := &Alloc{
Name_: name + "~", // "~" means "spilled"
Type_: pointer(obj.Type()),
pos: obj.Pos(),
}
f.objects[obj] = spill
f.Locals = append(f.Locals, spill)
f.emit(spill)
f.emit(&Store{Addr: spill, Val: param})
}
func (p *exporter) obj(obj types.Object) {
if trace {
p.tracef("object %s {\n", obj.Name())
defer p.tracef("}\n")
}
switch obj := obj.(type) {
case *types.Const:
p.int(constTag)
p.string(obj.Name())
p.typ(obj.Type())
p.value(obj.Val())
case *types.TypeName:
p.int(typeTag)
// name is written by corresponding named type
p.typ(obj.Type().(*types.Named))
case *types.Var:
p.int(varTag)
p.string(obj.Name())
p.typ(obj.Type())
case *types.Func:
p.int(funcTag)
p.string(obj.Name())
p.typ(obj.Type())
default:
panic(fmt.Sprintf("unexpected object type %T", obj))
}
}
func (r *renamer) checkExport(id *ast.Ident, pkg *types.Package, from types.Object) bool {
// Reject cross-package references if r.to is unexported.
// (Such references may be qualified identifiers or field/method
// selections.)
if !ast.IsExported(r.to) && pkg != from.Pkg() {
r.errorf(from.Pos(),
"renaming this %s %q to %q would make it unexported",
objectKind(from), from.Name(), r.to)
r.errorf(id.Pos(), "\tbreaking references from packages such as %q",
pkg.Path())
return false
}
return true
}
// ssaValueForIdent returns the ssa.Value for the ast.Ident whose path
// to the root of the AST is path. isAddr reports whether the
// ssa.Value is the address denoted by the ast.Ident, not its value.
//
func ssaValueForIdent(prog *ssa.Program, qinfo *importer.PackageInfo, obj types.Object, path []ast.Node) (value ssa.Value, isAddr bool, err error) {
switch obj := obj.(type) {
case *types.Var:
pkg := prog.Package(qinfo.Pkg)
pkg.Build()
if v, addr := prog.VarValue(obj, pkg, path); v != nil {
return v, addr, nil
}
return nil, false, fmt.Errorf("can't locate SSA Value for var %s", obj.Name())
case *types.Func:
return prog.FuncValue(obj), false, nil
}
panic(obj)
}
func (e *exporter) makeName(o types.Object) string {
switch o.Name() {
case "":
return "?"
case "_":
return "_"
default:
pkgPath := ""
if o.Pkg() != nil && o.Pkg() != e.pkg {
e.addImport(o.Pkg())
pkgPath = o.Pkg().Path()
}
return `@"` + pkgPath + `".` + o.Name()
}
}
func (p *printer) printObj(obj types.Object) {
p.print(obj.Name())
typ, basic := obj.Type().Underlying().(*types.Basic)
if basic && typ.Info()&types.IsUntyped != 0 {
// don't write untyped types
} else {
p.print(" ")
p.writeType(p.pkg, obj.Type())
}
if obj, ok := obj.(*types.Const); ok {
floatFmt := basic && typ.Info()&(types.IsFloat|types.IsComplex) != 0
p.print(" = ")
p.print(valString(obj.Val(), floatFmt))
}
}
func (cdd *CDD) Name(w *bytes.Buffer, obj types.Object, direct bool) {
if obj == nil {
w.WriteByte('_')
return
}
switch o := obj.(type) {
case *types.PkgName:
// Imported package name in SelectorExpr: pkgname.Name
w.WriteString(upath(o.Pkg().Path()))
return
case *types.Func:
s := o.Type().(*types.Signature)
if r := s.Recv(); r != nil {
t := r.Type()
if p, ok := t.(*types.Pointer); ok {
t = p.Elem()
direct = false
}
cdd.Type(w, t)
w.WriteByte('$')
w.WriteString(o.Name())
if !cdd.gtc.isLocal(t.(*types.Named).Obj()) {
cdd.addObject(o, direct)
}
return
}
}
if p := obj.Pkg(); p != nil && !cdd.gtc.isLocal(obj) {
cdd.addObject(obj, direct)
w.WriteString(upath(obj.Pkg().Path()))
w.WriteByte('$')
}
name := obj.Name()
switch name {
case "init":
w.WriteString(cdd.gtc.uniqueId() + name)
default:
w.WriteString(name)
if cdd.gtc.isLocal(obj) {
w.WriteByte('$')
}
}
}
// ssaValueForIdent returns the ssa.Value for the ast.Ident whose path
// to the root of the AST is path. It may return a nil Value without
// an error to indicate the pointer analysis is not appropriate.
//
func ssaValueForIdent(prog *ssa.Program, qinfo *importer.PackageInfo, obj types.Object, path []ast.Node) (ssa.Value, error) {
if obj, ok := obj.(*types.Var); ok {
pkg := prog.Package(qinfo.Pkg)
pkg.Build()
if v := prog.VarValue(obj, pkg, path); v != nil {
// Don't run pointer analysis on a ref to a const expression.
if _, ok := v.(*ssa.Const); ok {
v = nil
}
return v, nil
}
return nil, fmt.Errorf("can't locate SSA Value for var %s", obj.Name())
}
// Don't run pointer analysis on const/func objects.
return nil, nil
}
func (e *exporter) makeName(o types.Object) string {
if o.Name() == "" || o.Name() == "_" {
return "?"
}
if o.Pkg() == nil || o.Pkg() == e.pkg {
return `@"".` + o.Name()
}
e.addImport(o.Pkg())
return `@"` + o.Pkg().Path() + `".` + o.Name()
}
func (w *Walker) emitObj(obj types.Object) {
switch obj := obj.(type) {
case *types.Const:
w.emitf("const %s %s", obj.Name(), w.typeString(obj.Type()))
case *types.Var:
w.emitf("var %s %s", obj.Name(), w.typeString(obj.Type()))
case *types.TypeName:
w.emitType(obj)
case *types.Func:
w.emitFunc(obj)
default:
panic("unknown object: " + obj.String())
}
}
// createLocalVariableMetadata creates and returns a debug descriptor for
// a local variable in a function.
//
// obj is the go/types object for the var.
// paramIndex is 0 for "auto" variables (non-parameter stack vars), and a
// 1-based index for parameter vars.
func (c *compiler) createLocalVariableMetadata(obj types.Object, paramIndex int) llvm.DebugDescriptor {
ctx := c.currentDebugContext()
if ctx == nil {
return nil
}
tag := llvm.DW_TAG_auto_variable
if paramIndex > 0 {
tag = llvm.DW_TAG_arg_variable
}
position := c.fileset.Position(obj.Pos())
ld := llvm.NewLocalVariableDescriptor(tag)
ld.Argument = uint32(paramIndex)
ld.Line = uint32(position.Line)
ld.Name = obj.Name()
ld.File = &llvm.ContextDescriptor{llvm.FileDescriptor(position.Filename)}
ld.Type = c.tollvmDebugDescriptor(obj.Type())
ld.Context = ctx
return ld
}
// ssaValueForIdent returns the ssa.Value for the ast.Ident whose path
// to the root of the AST is path. isAddr reports whether the
// ssa.Value is the address denoted by the ast.Ident, not its value.
//
func ssaValueForIdent(prog *ssa.Program, qinfo *loader.PackageInfo, obj types.Object, path []ast.Node) (value ssa.Value, isAddr bool, err error) {
switch obj := obj.(type) {
case *types.Var:
pkg := prog.Package(qinfo.Pkg)
pkg.Build()
if v, addr := prog.VarValue(obj, pkg, path); v != nil {
return v, addr, nil
}
return nil, false, fmt.Errorf("can't locate SSA Value for var %s", obj.Name())
case *types.Func:
fn := prog.FuncValue(obj)
if fn == nil {
return nil, false, fmt.Errorf("%s is an interface method", obj)
}
// TODO(adonovan): there's no point running PTA on a *Func ident.
// Eliminate this feature.
return fn, false, nil
}
panic(obj)
}
func typeObjectToJson(o *types.Object) interface{} {
switch o := (*o).(type) {
case *types.Package:
return typePackageToJson(o)
case *types.Const:
return struct {
Isa string
Pkg interface{}
Name string
Type interface{}
Val interface{}
}{
"Const", typePackageToJson(o.Pkg()), o.Name(), typeTypeToJson(o.Type()), o.Val(),
}
case *types.TypeName:
return struct {
Isa string
Pkg interface{}
Name string
Type interface{}
}{
"TypeName", typePackageToJson(o.Pkg()), o.Name(), typeTypeToJson(o.Type()),
}
case *types.Var:
return struct {
Isa string
Pkg interface{}
Name string
Type interface{}
}{
"Var", typePackageToJson(o.Pkg()), o.Name(), typeTypeToJson(o.Type()),
}
case *types.Func:
return struct {
Isa string
Pkg interface{}
Name string
Type interface{}
}{
"Func", typePackageToJson(o.Pkg()), o.Name(), typeTypeToJson(o.Type()),
}
default:
if o != nil {
return nil
} else {
return "UNKNOWN"
}
}
return nil
}
func (f *File) checkNilFuncComparison(e *ast.BinaryExpr) {
if !vet("nilfunc") {
return
}
// Only want == or != comparisons.
if e.Op != token.EQL && e.Op != token.NEQ {
return
}
// Only want comparisons with a nil identifier on one side.
var e2 ast.Expr
switch {
case f.isNil(e.X):
e2 = e.Y
case f.isNil(e.Y):
e2 = e.X
default:
return
}
// Only want identifiers or selector expressions.
var obj types.Object
switch v := e2.(type) {
case *ast.Ident:
obj = f.pkg.idents[v]
case *ast.SelectorExpr:
obj = f.pkg.idents[v.Sel]
default:
return
}
// Only want functions.
if _, ok := obj.(*types.Func); !ok {
return
}
f.Badf(e.Pos(), "comparison of function %v %v nil is always %v", obj.Name(), e.Op, e.Op == token.NEQ)
}
func (c *PkgContext) objectName(o types.Object) string {
if o.Pkg() != nil && o.Pkg() != c.pkg {
pkgVar, found := c.pkgVars[o.Pkg().Path()]
if !found {
pkgVar = fmt.Sprintf(`Go$packages["%s"]`, o.Pkg().Path())
}
return pkgVar + "." + o.Name()
}
name, found := c.objectVars[o]
if !found {
name = c.newVariable(o.Name())
c.objectVars[o] = name
}
switch o.(type) {
case *types.Var, *types.Const:
if o.Parent() == c.pkg.Scope() {
return "Go$pkg." + name
}
}
return name
}
func (r *renamer) selectionConflict(from types.Object, delta int, syntax *ast.SelectorExpr, obj types.Object) {
r.errorf(from.Pos(), "renaming this %s %q to %q",
objectKind(from), from.Name(), r.to)
switch {
case delta < 0:
// analogous to sub-block conflict
r.errorf(syntax.Sel.Pos(),
"\twould change the referent of this selection")
r.errorf(obj.Pos(), "\tto this %s", objectKind(obj))
case delta == 0:
// analogous to same-block conflict
r.errorf(syntax.Sel.Pos(),
"\twould make this reference ambiguous")
r.errorf(obj.Pos(), "\twith this %s", objectKind(obj))
case delta > 0:
// analogous to super-block conflict
r.errorf(syntax.Sel.Pos(),
"\twould shadow this selection")
r.errorf(obj.Pos(), "\tto the %s declared here",
objectKind(obj))
}
}
// checkInPackageBlock performs safety checks for renames of
// func/var/const/type objects in the package block.
func (r *renamer) checkInPackageBlock(from types.Object) {
// Check that there are no references to the name from another
// package if the renaming would make it unexported.
if ast.IsExported(from.Name()) && !ast.IsExported(r.to) {
for pkg, info := range r.packages {
if pkg == from.Pkg() {
continue
}
if id := someUse(info, from); id != nil &&
!r.checkExport(id, pkg, from) {
break
}
}
}
info := r.packages[from.Pkg()]
lexinfo := lexical.Structure(r.iprog.Fset, from.Pkg(), &info.Info, info.Files)
// Check that in the package block, "init" is a function, and never referenced.
if r.to == "init" {
kind := objectKind(from)
if kind == "func" {
// Reject if intra-package references to it exist.
if refs := lexinfo.Refs[from]; len(refs) > 0 {
r.errorf(from.Pos(),
"renaming this func %q to %q would make it a package initializer",
from.Name(), r.to)
r.errorf(refs[0].Id.Pos(), "\tbut references to it exist")
}
} else {
r.errorf(from.Pos(), "you cannot have a %s at package level named %q",
kind, r.to)
}
}
// Check for conflicts between package block and all file blocks.
for _, f := range info.Files {
if prev, b := lexinfo.Blocks[f].Lookup(r.to); b == lexinfo.Blocks[f] {
r.errorf(from.Pos(), "renaming this %s %q to %q would conflict",
objectKind(from), from.Name(), r.to)
r.errorf(prev.Pos(), "\twith this %s",
objectKind(prev))
return // since checkInPackageBlock would report redundant errors
}
}
// Check for conflicts in lexical scope.
if from.Exported() {
for _, info := range r.packages {
r.checkInLexicalScope(from, info)
}
} else {
r.checkInLexicalScope(from, info)
}
}
func isAccessibleFrom(obj types.Object, pkg *types.Package) bool {
return ast.IsExported(obj.Name()) || obj.Pkg() == pkg
}
// checkSelection checks that all uses and selections that resolve to
// the specified object would continue to do so after the renaming.
func (r *renamer) checkSelections(from types.Object) {
for pkg, info := range r.packages {
if id := someUse(info, from); id != nil {
if !r.checkExport(id, pkg, from) {
return
}
}
for syntax, sel := range info.Selections {
// There may be extant selections of only the old
// name or only the new name, so we must check both.
// (If neither, the renaming is sound.)
//
// In both cases, we wish to compare the lengths
// of the implicit field path (Selection.Index)
// to see if the renaming would change it.
//
// If a selection that resolves to 'from', when renamed,
// would yield a path of the same or shorter length,
// this indicates ambiguity or a changed referent,
// analogous to same- or sub-block lexical conflict.
//
// If a selection using the name 'to' would
// yield a path of the same or shorter length,
// this indicates ambiguity or shadowing,
// analogous to same- or super-block lexical conflict.
// TODO(adonovan): fix: derive from Types[syntax.X].Mode
// TODO(adonovan): test with pointer, value, addressable value.
isAddressable := true
if sel.Obj() == from {
if obj, indices, _ := types.LookupFieldOrMethod(sel.Recv(), isAddressable, from.Pkg(), r.to); obj != nil {
// Renaming this existing selection of
// 'from' may block access to an existing
// type member named 'to'.
delta := len(indices) - len(sel.Index())
if delta > 0 {
continue // no ambiguity
}
r.selectionConflict(from, delta, syntax, obj)
return
}
} else if sel.Obj().Name() == r.to {
if obj, indices, _ := types.LookupFieldOrMethod(sel.Recv(), isAddressable, from.Pkg(), from.Name()); obj == from {
// Renaming 'from' may cause this existing
// selection of the name 'to' to change
// its meaning.
delta := len(indices) - len(sel.Index())
if delta > 0 {
continue // no ambiguity
}
r.selectionConflict(from, -delta, syntax, sel.Obj())
return
}
}
}
}
}
// checkInLexicalScope performs safety checks that a renaming does not
// change the lexical reference structure of the specified package.
//
// For objects in lexical scope, there are three kinds of conflicts:
// same-, sub-, and super-block conflicts. We will illustrate all three
// using this example:
//
// var x int
// var z int
//
// func f(y int) {
// print(x)
// print(y)
// }
//
// Renaming x to z encounters a SAME-BLOCK CONFLICT, because an object
// with the new name already exists, defined in the same lexical block
// as the old object.
//
// Renaming x to y encounters a SUB-BLOCK CONFLICT, because there exists
// a reference to x from within (what would become) a hole in its scope.
// The definition of y in an (inner) sub-block would cast a shadow in
// the scope of the renamed variable.
//
// Renaming y to x encounters a SUPER-BLOCK CONFLICT. This is the
// converse situation: there is an existing definition of the new name
// (x) in an (enclosing) super-block, and the renaming would create a
// hole in its scope, within which there exist references to it. The
// new name casts a shadow in scope of the existing definition of x in
// the super-block.
//
// Removing the old name (and all references to it) is always safe, and
// requires no checks.
//
func (r *renamer) checkInLexicalScope(from types.Object, info *loader.PackageInfo) {
lexinfo := lexical.Structure(r.iprog.Fset, info.Pkg, &info.Info, info.Files)
b := lexinfo.Defs[from] // the block defining the 'from' object
if b != nil {
to, toBlock := b.Lookup(r.to)
if toBlock == b {
// same-block conflict
r.errorf(from.Pos(), "renaming this %s %q to %q",
objectKind(from), from.Name(), r.to)
r.errorf(to.Pos(), "\tconflicts with %s in same block",
objectKind(to))
return
} else if toBlock != nil {
// Check for super-block conflict.
// The name r.to is defined in a superblock.
// Is that name referenced from within this block?
for _, ref := range lexinfo.Refs[to] {
if obj, _ := ref.Env.Lookup(from.Name()); obj == from {
// super-block conflict
r.errorf(from.Pos(), "renaming this %s %q to %q",
objectKind(from), from.Name(), r.to)
r.errorf(ref.Id.Pos(), "\twould shadow this reference")
r.errorf(to.Pos(), "\tto the %s declared here",
objectKind(to))
return
}
}
}
}
// Check for sub-block conflict.
// Is there an intervening definition of r.to between
// the block defining 'from' and some reference to it?
for _, ref := range lexinfo.Refs[from] {
// TODO(adonovan): think about dot imports.
// (Is b == fromBlock an invariant?)
_, fromBlock := ref.Env.Lookup(from.Name())
fromDepth := fromBlock.Depth()
to, toBlock := ref.Env.Lookup(r.to)
if to != nil {
// sub-block conflict
if toBlock.Depth() > fromDepth {
r.errorf(from.Pos(), "renaming this %s %q to %q",
objectKind(from), from.Name(), r.to)
r.errorf(ref.Id.Pos(), "\twould cause this reference to become shadowed")
r.errorf(to.Pos(), "\tby this intervening %s definition",
objectKind(to))
return
}
}
}
// Renaming a type that is used as an embedded field
// requires renaming the field too. e.g.
// type T int // if we rename this to U..
// var s struct {T}
// print(s.T) // ...this must change too
if _, ok := from.(*types.TypeName); ok {
for id, obj := range info.Uses {
if obj == from {
if field := info.Defs[id]; field != nil {
r.check(field)
}
}
}
}
}