--- /dev/null
+// Copyright 2019 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.
+//
+// Taken from golang.org/x/tools/refactor/rename.
+
+package source
+
+import (
+ "fmt"
+ "go/ast"
+ "go/token"
+ "go/types"
+ "reflect"
+ "strconv"
+ "strings"
+ "unicode"
+
+ "golang.org/x/tools/go/ast/astutil"
+ "golang.org/x/tools/refactor/satisfy"
+)
+
+// errorf reports an error (e.g. conflict) and prevents file modification.
+func (r *renamer) errorf(pos token.Pos, format string, args ...interface{}) {
+ r.hadConflicts = true
+ r.errors += fmt.Sprintf(format, args...)
+}
+
+// check performs safety checks of the renaming of the 'from' object to r.to.
+func (r *renamer) check(from types.Object) {
+ if r.objsToUpdate[from] {
+ return
+ }
+ r.objsToUpdate[from] = true
+
+ // NB: order of conditions is important.
+ if from_, ok := from.(*types.PkgName); ok {
+ r.checkInFileBlock(from_)
+ } else if from_, ok := from.(*types.Label); ok {
+ r.checkLabel(from_)
+ } else if isPackageLevel(from) {
+ r.checkInPackageBlock(from)
+ } else if v, ok := from.(*types.Var); ok && v.IsField() {
+ r.checkStructField(v)
+ } else if f, ok := from.(*types.Func); ok && recv(f) != nil {
+ r.checkMethod(f)
+ } else if isLocal(from) {
+ r.checkInLocalScope(from)
+ } else {
+ r.errorf(from.Pos(), "unexpected %s object %q (please report a bug)\n",
+ objectKind(from), from)
+ }
+}
+
+// checkInFileBlock performs safety checks for renames of objects in the file block,
+// i.e. imported package names.
+func (r *renamer) checkInFileBlock(from *types.PkgName) {
+ // Check import name is not "init".
+ if r.to == "init" {
+ r.errorf(from.Pos(), "%q is not a valid imported package name", r.to)
+ }
+
+ // Check for conflicts between file and package block.
+ if prev := from.Pkg().Scope().Lookup(r.to); prev != nil {
+ r.errorf(from.Pos(), "renaming this %s %q to %q would conflict",
+ objectKind(from), from.Name(), r.to)
+ r.errorf(prev.Pos(), "\twith this package member %s",
+ objectKind(prev))
+ return // since checkInPackageBlock would report redundant errors
+ }
+
+ // Check for conflicts in lexical scope.
+ r.checkInLexicalScope(from, r.packages[from.Pkg()])
+}
+
+// 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 typ, pkg := range r.packages {
+ if typ == from.Pkg() {
+ continue
+ }
+ if id := someUse(pkg.GetTypesInfo(), from); id != nil &&
+ !r.checkExport(id, typ, from) {
+ break
+ }
+ }
+ }
+
+ pkg := r.packages[from.Pkg()]
+ if pkg == nil {
+ return
+ }
+
+ // 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.
+ for id, obj := range pkg.GetTypesInfo().Uses {
+ if obj == from {
+ r.errorf(from.Pos(),
+ "renaming this func %q to %q would make it a package initializer",
+ from.Name(), r.to)
+ r.errorf(id.Pos(), "\tbut references to it exist")
+ break
+ }
+ }
+ } 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 pkg.GetSyntax() {
+ fileScope := pkg.GetTypesInfo().Scopes[f]
+ b, prev := fileScope.LookupParent(r.to, token.NoPos)
+ if b == fileScope {
+ r.errorf(from.Pos(), "renaming this %s %q to %q would conflict", objectKind(from), from.Name(), r.to)
+ var prevPos token.Pos
+ if prev != nil {
+ prevPos = prev.Pos()
+ }
+ r.errorf(prevPos, "\twith this %s", objectKind(prev))
+ return // since checkInPackageBlock would report redundant errors
+ }
+ }
+
+ // Check for conflicts in lexical scope.
+ if from.Exported() {
+ for _, pkg := range r.packages {
+ r.checkInLexicalScope(from, pkg)
+ }
+ } else {
+ r.checkInLexicalScope(from, pkg)
+ }
+}
+
+func (r *renamer) checkInLocalScope(from types.Object) {
+ pkg := r.packages[from.Pkg()]
+ r.checkInLexicalScope(from, pkg)
+}
+
+// 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, pkg Package) {
+ b := from.Parent() // the block defining the 'from' object
+ if b != nil {
+ toBlock, to := b.LookupParent(r.to, from.Parent().End())
+ 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?
+ forEachLexicalRef(pkg, to, func(id *ast.Ident, block *types.Scope) bool {
+ _, obj := lexicalLookup(block, from.Name(), id.Pos())
+ if obj == from {
+ // super-block conflict
+ r.errorf(from.Pos(), "renaming this %s %q to %q",
+ objectKind(from), from.Name(), r.to)
+ r.errorf(id.Pos(), "\twould shadow this reference")
+ r.errorf(to.Pos(), "\tto the %s declared here",
+ objectKind(to))
+ return false // stop
+ }
+ return true
+ })
+ }
+ }
+ // Check for sub-block conflict.
+ // Is there an intervening definition of r.to between
+ // the block defining 'from' and some reference to it?
+ forEachLexicalRef(pkg, from, func(id *ast.Ident, block *types.Scope) bool {
+ // Find the block that defines the found reference.
+ // It may be an ancestor.
+ fromBlock, _ := lexicalLookup(block, from.Name(), id.Pos())
+
+ // See what r.to would resolve to in the same scope.
+ toBlock, to := lexicalLookup(block, r.to, id.Pos())
+ if to != nil {
+ // sub-block conflict
+ if deeper(toBlock, fromBlock) {
+ r.errorf(from.Pos(), "renaming this %s %q to %q",
+ objectKind(from), from.Name(), r.to)
+ r.errorf(id.Pos(), "\twould cause this reference to become shadowed")
+ r.errorf(to.Pos(), "\tby this intervening %s definition",
+ objectKind(to))
+ return false // stop
+ }
+ }
+ return true
+ })
+
+ // 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 pkg.GetTypesInfo().Uses {
+ if obj == from {
+ if field := pkg.GetTypesInfo().Defs[id]; field != nil {
+ r.check(field)
+ }
+ }
+ }
+ }
+}
+
+// lexicalLookup is like (*types.Scope).LookupParent but respects the
+// environment visible at pos. It assumes the relative position
+// information is correct with each file.
+func lexicalLookup(block *types.Scope, name string, pos token.Pos) (*types.Scope, types.Object) {
+ for b := block; b != nil; b = b.Parent() {
+ obj := b.Lookup(name)
+ // The scope of a package-level object is the entire package,
+ // so ignore pos in that case.
+ // No analogous clause is needed for file-level objects
+ // since no reference can appear before an import decl.
+ if obj == nil || obj.Pkg() == nil {
+ continue
+ }
+ if b == obj.Pkg().Scope() || obj.Pos() < pos {
+ return b, obj
+ }
+ }
+ return nil, nil
+}
+
+// deeper reports whether block x is lexically deeper than y.
+func deeper(x, y *types.Scope) bool {
+ if x == y || x == nil {
+ return false
+ } else if y == nil {
+ return true
+ } else {
+ return deeper(x.Parent(), y.Parent())
+ }
+}
+
+// forEachLexicalRef calls fn(id, block) for each identifier id in package
+// pkg that is a reference to obj in lexical scope. block is the
+// lexical block enclosing the reference. If fn returns false the
+// iteration is terminated and findLexicalRefs returns false.
+func forEachLexicalRef(pkg Package, obj types.Object, fn func(id *ast.Ident, block *types.Scope) bool) bool {
+ ok := true
+ var stack []ast.Node
+
+ var visit func(n ast.Node) bool
+ visit = func(n ast.Node) bool {
+ if n == nil {
+ stack = stack[:len(stack)-1] // pop
+ return false
+ }
+ if !ok {
+ return false // bail out
+ }
+
+ stack = append(stack, n) // push
+ switch n := n.(type) {
+ case *ast.Ident:
+ if pkg.GetTypesInfo().Uses[n] == obj {
+ block := enclosingBlock(pkg.GetTypesInfo(), stack)
+ if !fn(n, block) {
+ ok = false
+ }
+ }
+ return visit(nil) // pop stack
+
+ case *ast.SelectorExpr:
+ // don't visit n.Sel
+ ast.Inspect(n.X, visit)
+ return visit(nil) // pop stack, don't descend
+
+ case *ast.CompositeLit:
+ // Handle recursion ourselves for struct literals
+ // so we don't visit field identifiers.
+ tv, ok := pkg.GetTypesInfo().Types[n]
+ if !ok {
+ return visit(nil) // pop stack, don't descend
+ }
+ if _, ok := Deref(tv.Type).Underlying().(*types.Struct); ok {
+ if n.Type != nil {
+ ast.Inspect(n.Type, visit)
+ }
+ for _, elt := range n.Elts {
+ if kv, ok := elt.(*ast.KeyValueExpr); ok {
+ ast.Inspect(kv.Value, visit)
+ } else {
+ ast.Inspect(elt, visit)
+ }
+ }
+ return visit(nil) // pop stack, don't descend
+ }
+ }
+ return true
+ }
+
+ for _, f := range pkg.GetSyntax() {
+ ast.Inspect(f, visit)
+ if len(stack) != 0 {
+ panic(stack)
+ }
+ if !ok {
+ break
+ }
+ }
+ return ok
+}
+
+// enclosingBlock returns the innermost block enclosing the specified
+// AST node, specified in the form of a path from the root of the file,
+// [file...n].
+func enclosingBlock(info *types.Info, stack []ast.Node) *types.Scope {
+ for i := range stack {
+ n := stack[len(stack)-1-i]
+ // For some reason, go/types always associates a
+ // function's scope with its FuncType.
+ // TODO(adonovan): feature or a bug?
+ switch f := n.(type) {
+ case *ast.FuncDecl:
+ n = f.Type
+ case *ast.FuncLit:
+ n = f.Type
+ }
+ if b := info.Scopes[n]; b != nil {
+ return b
+ }
+ }
+ panic("no Scope for *ast.File")
+}
+
+func (r *renamer) checkLabel(label *types.Label) {
+ // Check there are no identical labels in the function's label block.
+ // (Label blocks don't nest, so this is easy.)
+ if prev := label.Parent().Lookup(r.to); prev != nil {
+ r.errorf(label.Pos(), "renaming this label %q to %q", label.Name(), prev.Name())
+ r.errorf(prev.Pos(), "\twould conflict with this one")
+ }
+}
+
+// checkStructField checks that the field renaming will not cause
+// conflicts at its declaration, or ambiguity or changes to any selection.
+func (r *renamer) checkStructField(from *types.Var) {
+ // Check that the struct declaration is free of field conflicts,
+ // and field/method conflicts.
+
+ // go/types offers no easy way to get from a field (or interface
+ // method) to its declaring struct (or interface), so we must
+ // ascend the AST.
+ fromPkg, ok := r.packages[from.Pkg()]
+ if !ok {
+ return
+ }
+ pkg, path, _ := pathEnclosingInterval(r.fset, fromPkg, from.Pos(), from.Pos())
+ if pkg == nil || path == nil {
+ return
+ }
+ // path matches this pattern:
+ // [Ident SelectorExpr? StarExpr? Field FieldList StructType ParenExpr* ... File]
+
+ // Ascend to FieldList.
+ var i int
+ for {
+ if _, ok := path[i].(*ast.FieldList); ok {
+ break
+ }
+ i++
+ }
+ i++
+ tStruct := path[i].(*ast.StructType)
+ i++
+ // Ascend past parens (unlikely).
+ for {
+ _, ok := path[i].(*ast.ParenExpr)
+ if !ok {
+ break
+ }
+ i++
+ }
+ if spec, ok := path[i].(*ast.TypeSpec); ok {
+ // This struct is also a named type.
+ // We must check for direct (non-promoted) field/field
+ // and method/field conflicts.
+ named := pkg.GetTypesInfo().Defs[spec.Name].Type()
+ prev, indices, _ := types.LookupFieldOrMethod(named, true, pkg.GetTypes(), r.to)
+ if len(indices) == 1 {
+ r.errorf(from.Pos(), "renaming this field %q to %q",
+ from.Name(), r.to)
+ r.errorf(prev.Pos(), "\twould conflict with this %s",
+ objectKind(prev))
+ return // skip checkSelections to avoid redundant errors
+ }
+ } else {
+ // This struct is not a named type.
+ // We need only check for direct (non-promoted) field/field conflicts.
+ T := pkg.GetTypesInfo().Types[tStruct].Type.Underlying().(*types.Struct)
+ for i := 0; i < T.NumFields(); i++ {
+ if prev := T.Field(i); prev.Name() == r.to {
+ r.errorf(from.Pos(), "renaming this field %q to %q",
+ from.Name(), r.to)
+ r.errorf(prev.Pos(), "\twould conflict with this field")
+ return // skip checkSelections to avoid redundant errors
+ }
+ }
+ }
+
+ // Renaming an anonymous field requires renaming the type too. e.g.
+ // print(s.T) // if we rename T to U,
+ // type T int // this and
+ // var s struct {T} // this must change too.
+ if from.Anonymous() {
+ if named, ok := from.Type().(*types.Named); ok {
+ r.check(named.Obj())
+ } else if named, ok := Deref(from.Type()).(*types.Named); ok {
+ r.check(named.Obj())
+ }
+ }
+
+ // Check integrity of existing (field and method) selections.
+ r.checkSelections(from)
+}
+
+// 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 typ, pkg := range r.packages {
+ if id := someUse(pkg.GetTypesInfo(), from); id != nil {
+ if !r.checkExport(id, typ, from) {
+ return
+ }
+ }
+
+ for syntax, sel := range pkg.GetTypesInfo().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
+ }
+ }
+ }
+ }
+}
+
+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(), "\tof 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(), "\tof the %s declared here",
+ objectKind(obj))
+ }
+}
+
+// checkMethod performs safety checks for renaming a method.
+// There are three hazards:
+// - declaration conflicts
+// - selection ambiguity/changes
+// - entailed renamings of assignable concrete/interface types.
+// We reject renamings initiated at concrete methods if it would
+// change the assignability relation. For renamings of abstract
+// methods, we rename all methods transitively coupled to it via
+// assignability.
+func (r *renamer) checkMethod(from *types.Func) {
+ // e.g. error.Error
+ if from.Pkg() == nil {
+ r.errorf(from.Pos(), "you cannot rename built-in method %s", from)
+ return
+ }
+
+ // ASSIGNABILITY: We reject renamings of concrete methods that
+ // would break a 'satisfy' constraint; but renamings of abstract
+ // methods are allowed to proceed, and we rename affected
+ // concrete and abstract methods as necessary. It is the
+ // initial method that determines the policy.
+
+ // Check for conflict at point of declaration.
+ // Check to ensure preservation of assignability requirements.
+ R := recv(from).Type()
+ if IsInterface(R) {
+ // Abstract method
+
+ // declaration
+ prev, _, _ := types.LookupFieldOrMethod(R, false, from.Pkg(), r.to)
+ if prev != nil {
+ r.errorf(from.Pos(), "renaming this interface method %q to %q",
+ from.Name(), r.to)
+ r.errorf(prev.Pos(), "\twould conflict with this method")
+ return
+ }
+
+ // Check all interfaces that embed this one for
+ // declaration conflicts too.
+ for _, pkg := range r.packages {
+ // Start with named interface types (better errors)
+ for _, obj := range pkg.GetTypesInfo().Defs {
+ if obj, ok := obj.(*types.TypeName); ok && IsInterface(obj.Type()) {
+ f, _, _ := types.LookupFieldOrMethod(
+ obj.Type(), false, from.Pkg(), from.Name())
+ if f == nil {
+ continue
+ }
+ t, _, _ := types.LookupFieldOrMethod(
+ obj.Type(), false, from.Pkg(), r.to)
+ if t == nil {
+ continue
+ }
+ r.errorf(from.Pos(), "renaming this interface method %q to %q",
+ from.Name(), r.to)
+ r.errorf(t.Pos(), "\twould conflict with this method")
+ r.errorf(obj.Pos(), "\tin named interface type %q", obj.Name())
+ }
+ }
+
+ // Now look at all literal interface types (includes named ones again).
+ for e, tv := range pkg.GetTypesInfo().Types {
+ if e, ok := e.(*ast.InterfaceType); ok {
+ _ = e
+ _ = tv.Type.(*types.Interface)
+ // TODO(adonovan): implement same check as above.
+ }
+ }
+ }
+
+ // assignability
+ //
+ // Find the set of concrete or abstract methods directly
+ // coupled to abstract method 'from' by some
+ // satisfy.Constraint, and rename them too.
+ for key := range r.satisfy() {
+ // key = (lhs, rhs) where lhs is always an interface.
+
+ lsel := r.msets.MethodSet(key.LHS).Lookup(from.Pkg(), from.Name())
+ if lsel == nil {
+ continue
+ }
+ rmethods := r.msets.MethodSet(key.RHS)
+ rsel := rmethods.Lookup(from.Pkg(), from.Name())
+ if rsel == nil {
+ continue
+ }
+
+ // If both sides have a method of this name,
+ // and one of them is m, the other must be coupled.
+ var coupled *types.Func
+ switch from {
+ case lsel.Obj():
+ coupled = rsel.Obj().(*types.Func)
+ case rsel.Obj():
+ coupled = lsel.Obj().(*types.Func)
+ default:
+ continue
+ }
+
+ // We must treat concrete-to-interface
+ // constraints like an implicit selection C.f of
+ // each interface method I.f, and check that the
+ // renaming leaves the selection unchanged and
+ // unambiguous.
+ //
+ // Fun fact: the implicit selection of C.f
+ // type I interface{f()}
+ // type C struct{I}
+ // func (C) g()
+ // var _ I = C{} // here
+ // yields abstract method I.f. This can make error
+ // messages less than obvious.
+ //
+ if !IsInterface(key.RHS) {
+ // The logic below was derived from checkSelections.
+
+ rtosel := rmethods.Lookup(from.Pkg(), r.to)
+ if rtosel != nil {
+ rto := rtosel.Obj().(*types.Func)
+ delta := len(rsel.Index()) - len(rtosel.Index())
+ if delta < 0 {
+ continue // no ambiguity
+ }
+
+ // TODO(adonovan): record the constraint's position.
+ keyPos := token.NoPos
+
+ r.errorf(from.Pos(), "renaming this method %q to %q",
+ from.Name(), r.to)
+ if delta == 0 {
+ // analogous to same-block conflict
+ r.errorf(keyPos, "\twould make the %s method of %s invoked via interface %s ambiguous",
+ r.to, key.RHS, key.LHS)
+ r.errorf(rto.Pos(), "\twith (%s).%s",
+ recv(rto).Type(), r.to)
+ } else {
+ // analogous to super-block conflict
+ r.errorf(keyPos, "\twould change the %s method of %s invoked via interface %s",
+ r.to, key.RHS, key.LHS)
+ r.errorf(coupled.Pos(), "\tfrom (%s).%s",
+ recv(coupled).Type(), r.to)
+ r.errorf(rto.Pos(), "\tto (%s).%s",
+ recv(rto).Type(), r.to)
+ }
+ return // one error is enough
+ }
+ }
+
+ if !r.changeMethods {
+ // This should be unreachable.
+ r.errorf(from.Pos(), "internal error: during renaming of abstract method %s", from)
+ r.errorf(coupled.Pos(), "\tchangedMethods=false, coupled method=%s", coupled)
+ r.errorf(from.Pos(), "\tPlease file a bug report")
+ return
+ }
+
+ // Rename the coupled method to preserve assignability.
+ r.check(coupled)
+ }
+ } else {
+ // Concrete method
+
+ // declaration
+ prev, indices, _ := types.LookupFieldOrMethod(R, true, from.Pkg(), r.to)
+ if prev != nil && len(indices) == 1 {
+ r.errorf(from.Pos(), "renaming this method %q to %q",
+ from.Name(), r.to)
+ r.errorf(prev.Pos(), "\twould conflict with this %s",
+ objectKind(prev))
+ return
+ }
+
+ // assignability
+ //
+ // Find the set of abstract methods coupled to concrete
+ // method 'from' by some satisfy.Constraint, and rename
+ // them too.
+ //
+ // Coupling may be indirect, e.g. I.f <-> C.f via type D.
+ //
+ // type I interface {f()}
+ // type C int
+ // type (C) f()
+ // type D struct{C}
+ // var _ I = D{}
+ //
+ for key := range r.satisfy() {
+ // key = (lhs, rhs) where lhs is always an interface.
+ if IsInterface(key.RHS) {
+ continue
+ }
+ rsel := r.msets.MethodSet(key.RHS).Lookup(from.Pkg(), from.Name())
+ if rsel == nil || rsel.Obj() != from {
+ continue // rhs does not have the method
+ }
+ lsel := r.msets.MethodSet(key.LHS).Lookup(from.Pkg(), from.Name())
+ if lsel == nil {
+ continue
+ }
+ imeth := lsel.Obj().(*types.Func)
+
+ // imeth is the abstract method (e.g. I.f)
+ // and key.RHS is the concrete coupling type (e.g. D).
+ if !r.changeMethods {
+ r.errorf(from.Pos(), "renaming this method %q to %q",
+ from.Name(), r.to)
+ var pos token.Pos
+ var iface string
+
+ I := recv(imeth).Type()
+ if named, ok := I.(*types.Named); ok {
+ pos = named.Obj().Pos()
+ iface = "interface " + named.Obj().Name()
+ } else {
+ pos = from.Pos()
+ iface = I.String()
+ }
+ r.errorf(pos, "\twould make %s no longer assignable to %s",
+ key.RHS, iface)
+ r.errorf(imeth.Pos(), "\t(rename %s.%s if you intend to change both types)",
+ I, from.Name())
+ return // one error is enough
+ }
+
+ // Rename the coupled interface method to preserve assignability.
+ r.check(imeth)
+ }
+ }
+
+ // Check integrity of existing (field and method) selections.
+ // We skip this if there were errors above, to avoid redundant errors.
+ r.checkSelections(from)
+}
+
+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 %q to %q would make it unexported",
+ from.Name(), r.to)
+ r.errorf(id.Pos(), "\tbreaking references from packages such as %q",
+ pkg.Path())
+ return false
+ }
+ return true
+}
+
+// satisfy returns the set of interface satisfaction constraints.
+func (r *renamer) satisfy() map[satisfy.Constraint]bool {
+ if r.satisfyConstraints == nil {
+ // Compute on demand: it's expensive.
+ var f satisfy.Finder
+ for _, pkg := range r.packages {
+ // From satisfy.Finder documentation:
+ //
+ // The package must be free of type errors, and
+ // info.{Defs,Uses,Selections,Types} must have been populated by the
+ // type-checker.
+ //
+ // Only proceed if all packages have no errors.
+ if pkg.HasListOrParseErrors() || pkg.HasTypeErrors() {
+ r.errorf(token.NoPos, // we don't have a position for this error.
+ "renaming %q to %q not possible because %q has errors",
+ r.from, r.to, pkg.PkgPath())
+ return nil
+ }
+ f.Find(pkg.GetTypesInfo(), pkg.GetSyntax())
+ }
+ r.satisfyConstraints = f.Result
+ }
+ return r.satisfyConstraints
+}
+
+// -- helpers ----------------------------------------------------------
+
+// recv returns the method's receiver.
+func recv(meth *types.Func) *types.Var {
+ return meth.Type().(*types.Signature).Recv()
+}
+
+// someUse returns an arbitrary use of obj within info.
+func someUse(info *types.Info, obj types.Object) *ast.Ident {
+ for id, o := range info.Uses {
+ if o == obj {
+ return id
+ }
+ }
+ return nil
+}
+
+// pathEnclosingInterval returns the Package and ast.Node that
+// contain source interval [start, end), and all the node's ancestors
+// up to the AST root. It searches all ast.Files of all packages.
+// exact is defined as for astutil.PathEnclosingInterval.
+//
+// The zero value is returned if not found.
+//
+func pathEnclosingInterval(fset *token.FileSet, pkg Package, start, end token.Pos) (resPkg Package, path []ast.Node, exact bool) {
+ pkgs := []Package{pkg}
+ for _, f := range pkg.GetSyntax() {
+ for _, imp := range f.Imports {
+ if imp == nil {
+ continue
+ }
+ importPath, err := strconv.Unquote(imp.Path.Value)
+ if err != nil {
+ continue
+ }
+ importPkg, err := pkg.GetImport(importPath)
+ if err != nil {
+ return nil, nil, false
+ }
+ pkgs = append(pkgs, importPkg)
+ }
+ }
+ for _, p := range pkgs {
+ for _, f := range p.GetSyntax() {
+ if f.Pos() == token.NoPos {
+ // This can happen if the parser saw
+ // too many errors and bailed out.
+ // (Use parser.AllErrors to prevent that.)
+ continue
+ }
+ if !tokenFileContainsPos(fset.File(f.Pos()), start) {
+ continue
+ }
+ if path, exact := astutil.PathEnclosingInterval(f, start, end); path != nil {
+ return pkg, path, exact
+ }
+ }
+ }
+ return nil, nil, false
+}
+
+// TODO(adonovan): make this a method: func (*token.File) Contains(token.Pos)
+func tokenFileContainsPos(f *token.File, pos token.Pos) bool {
+ p := int(pos)
+ base := f.Base()
+ return base <= p && p < base+f.Size()
+}
+
+func objectKind(obj types.Object) string {
+ if obj == nil {
+ return "nil object"
+ }
+ switch obj := obj.(type) {
+ case *types.PkgName:
+ return "imported package name"
+ case *types.TypeName:
+ return "type"
+ case *types.Var:
+ if obj.IsField() {
+ return "field"
+ }
+ case *types.Func:
+ if obj.Type().(*types.Signature).Recv() != nil {
+ return "method"
+ }
+ }
+ // label, func, var, const
+ return strings.ToLower(strings.TrimPrefix(reflect.TypeOf(obj).String(), "*types."))
+}
+
+// NB: for renamings, blank is not considered valid.
+func isValidIdentifier(id string) bool {
+ if id == "" || id == "_" {
+ return false
+ }
+ for i, r := range id {
+ if !isLetter(r) && (i == 0 || !isDigit(r)) {
+ return false
+ }
+ }
+ return token.Lookup(id) == token.IDENT
+}
+
+// isLocal reports whether obj is local to some function.
+// Precondition: not a struct field or interface method.
+func isLocal(obj types.Object) bool {
+ // [... 5=stmt 4=func 3=file 2=pkg 1=universe]
+ var depth int
+ for scope := obj.Parent(); scope != nil; scope = scope.Parent() {
+ depth++
+ }
+ return depth >= 4
+}
+
+func isPackageLevel(obj types.Object) bool {
+ if obj == nil {
+ return false
+ }
+ return obj.Pkg().Scope().Lookup(obj.Name()) == obj
+}
+
+// -- Plundered from go/scanner: ---------------------------------------
+
+func isLetter(ch rune) bool {
+ return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_' || ch >= 0x80 && unicode.IsLetter(ch)
+}
+
+func isDigit(ch rune) bool {
+ return '0' <= ch && ch <= '9' || ch >= 0x80 && unicode.IsDigit(ch)
+}
projects / dotfiles / .git / blobdiff