+++ /dev/null
-// Copyright 2014 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 rename
-
-// This file defines the safety checks for each kind of renaming.
-
-import (
- "fmt"
- "go/ast"
- "go/token"
- "go/types"
-
- "golang.org/x/tools/go/loader"
- "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
- reportError(r.iprog.Fset.Position(pos), 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()])
-
- // Finally, modify ImportSpec syntax to add or remove the Name as needed.
- info, path, _ := r.iprog.PathEnclosingInterval(from.Pos(), from.Pos())
- if from.Imported().Name() == r.to {
- // ImportSpec.Name not needed
- path[1].(*ast.ImportSpec).Name = nil
- } else {
- // ImportSpec.Name needed
- if spec := path[1].(*ast.ImportSpec); spec.Name == nil {
- spec.Name = &ast.Ident{NamePos: spec.Path.Pos(), Name: r.to}
- info.Defs[spec.Name] = from
- }
- }
-}
-
-// 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()]
-
- // 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 info.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 info.Files {
- fileScope := info.Info.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)
- 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 (r *renamer) checkInLocalScope(from types.Object) {
- info := r.packages[from.Pkg()]
-
- // Is this object an implicit local var for a type switch?
- // Each case has its own var, whose position is the decl of y,
- // but Ident in that decl does not appear in the Uses map.
- //
- // switch y := x.(type) { // Defs[Ident(y)] is undefined
- // case int: print(y) // Implicits[CaseClause(int)] = Var(y_int)
- // case string: print(y) // Implicits[CaseClause(string)] = Var(y_string)
- // }
- //
- var isCaseVar bool
- for syntax, obj := range info.Implicits {
- if _, ok := syntax.(*ast.CaseClause); ok && obj.Pos() == from.Pos() {
- isCaseVar = true
- r.check(obj)
- }
- }
-
- r.checkInLexicalScope(from, info)
-
- // Finally, if this was a type switch, change the variable y.
- if isCaseVar {
- _, path, _ := r.iprog.PathEnclosingInterval(from.Pos(), from.Pos())
- path[0].(*ast.Ident).Name = r.to // path is [Ident AssignStmt TypeSwitchStmt...]
- }
-}
-
-// 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) {
- 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(info, 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(info, 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 info.Uses {
- if obj == from {
- if field := info.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 && (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
-// info 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(info *loader.PackageInfo, 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 info.Uses[n] == obj {
- block := enclosingBlock(&info.Info, 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 := info.Types[n]
- 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 info.Files {
- 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.
- info, path, _ := r.iprog.PathEnclosingInterval(from.Pos(), from.Pos())
- // 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 := info.Defs[spec.Name].Type()
- prev, indices, _ := types.LookupFieldOrMethod(named, true, info.Pkg, 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 := info.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 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
- }
- }
- }
- }
-}
-
-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 _, info := range r.packages {
- // Start with named interface types (better errors)
- for _, obj := range info.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 info.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 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
-}
-
-// 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 _, info := range r.packages {
- f.Find(&info.Info, info.Files)
- }
- 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 *loader.PackageInfo, obj types.Object) *ast.Ident {
- for id, o := range info.Uses {
- if o == obj {
- return id
- }
- }
- return nil
-}
-
-// -- Plundered from golang.org/x/tools/go/ssa -----------------
-
-func isInterface(T types.Type) bool { return types.IsInterface(T) }
-
-func deref(typ types.Type) types.Type {
- if p, _ := typ.(*types.Pointer); p != nil {
- return p.Elem()
- }
- return typ
-}
projects / dotfiles / .git / blobdiff