diff options
Diffstat (limited to 'gopls/internal/lsp/source/rename_check.go')
| -rw-r--r-- | gopls/internal/lsp/source/rename_check.go | 921 |
1 files changed, 921 insertions, 0 deletions
diff --git a/gopls/internal/lsp/source/rename_check.go b/gopls/internal/lsp/source/rename_check.go new file mode 100644 index 000000000..a858bb7fa --- /dev/null +++ b/gopls/internal/lsp/source/rename_check.go @@ -0,0 +1,921 @@ +// 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 + +// This file defines the conflict-checking portion of the rename operation. +// +// The renamer works on a single package of type-checked syntax, and +// is called in parallel for all necessary packages in the workspace, +// possibly up to the transitive reverse dependencies of the +// declaration. Finally the union of all edits and errors is computed. +// +// Renaming one object may entail renaming of others. For example: +// +// - An embedded field couples a Var (field) and a TypeName. +// So, renaming either one requires renaming the other. +// If the initial object is an embedded field, we must add its +// TypeName (and its enclosing package) to the renaming set; +// this is easily discovered at the outset. +// +// Conversely, if the initial object is a TypeName, we must observe +// whether any of its references (from directly importing packages) +// is coincident with an embedded field Var and, if so, initiate a +// renaming of it. +// +// - A method of an interface type is coupled to all corresponding +// methods of types that are assigned to the interface (as +// discovered by the 'satisfy' pass). As a matter of usability, we +// require that such renamings be initiated from the interface +// method, not the concrete method. + +import ( + "fmt" + "go/ast" + "go/token" + "go/types" + "path/filepath" + "reflect" + "strings" + "unicode" + + "golang.org/x/tools/go/ast/astutil" + "golang.org/x/tools/gopls/internal/lsp/safetoken" + "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{}) { + // Conflict error messages in the old gorename tool (whence this + // logic originated) contain rich information associated with + // multiple source lines, such as: + // + // p/a.go:1:2: renaming "x" to "y" here + // p/b.go:3:4: \t would cause this reference to "y" + // p/c.go:5:5: \t to become shadowed by this intervening declaration. + // + // Unfortunately LSP provides no means to transmit the + // structure of this error, so we format the positions briefly + // using dir/file.go where dir is the base name of the parent + // directory. + + var conflict strings.Builder + + // Add prefix of (truncated) position. + if pos != token.NoPos { + // TODO(adonovan): skip position of first error if it is + // on the same line as the renaming itself. + posn := safetoken.StartPosition(r.pkg.FileSet(), pos).String() + segments := strings.Split(filepath.ToSlash(posn), "/") + if n := len(segments); n > 2 { + segments = segments[n-2:] + } + posn = strings.Join(segments, "/") + fmt.Fprintf(&conflict, "%s:", posn) + + if !strings.HasPrefix(format, "\t") { + conflict.WriteByte(' ') + } + } + + fmt.Fprintf(&conflict, format, args...) + r.conflicts = append(r.conflicts, conflict.String()) +} + +// 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.checkInLexicalScope(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) +} + +// 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 typ := r.pkg.GetTypes(); typ != from.Pkg() && ast.IsExported(r.from) && !ast.IsExported(r.to) { + if id := someUse(r.pkg.GetTypesInfo(), from); id != nil { + r.checkExport(id, typ, from) + } + } + + // 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 r.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 r.pkg.GetSyntax() { + fileScope := r.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. + r.checkInLexicalScope(from) +} + +// 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 shadows 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) { + 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(r.pkg, to, func(id *ast.Ident, block *types.Scope) bool { + _, obj := block.LookupParent(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(r.pkg, from, func(id *ast.Ident, block *types.Scope) bool { + // Find the block that defines the found reference. + // It may be an ancestor. + fromBlock, _ := block.LookupParent(from.Name(), id.Pos()) + // See what r.to would resolve to in the same scope. + toBlock, to := block.LookupParent(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 r.pkg.GetTypesInfo().Uses { + if obj == from { + if field := r.pkg.GetTypesInfo().Defs[id]; field != nil { + r.check(field) + } + } + } + } +} + +// 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. + pgf, ok := enclosingFile(r.pkg, from.Pos()) + if !ok { + return // not declared by syntax of this package + } + path, _ := astutil.PathEnclosingInterval(pgf.File, 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 := r.pkg.GetTypesInfo().Defs[spec.Name].Type() + prev, indices, _ := types.LookupFieldOrMethod(named, true, r.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 := r.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) +} + +// checkSelections 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) { + pkg := r.pkg + typ := pkg.GetTypes() + { + 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 types.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. + { + // Start with named interface types (better errors) + for _, obj := range r.pkg.GetTypesInfo().Defs { + if obj, ok := obj.(*types.TypeName); ok && types.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 r.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 !types.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 types.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 + pkg := r.pkg + { + // 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.HasParseErrors() || 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.Metadata().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 +} + +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) +} |