github.com/april1989/origin-go-tools@v0.0.32/internal/lsp/source/rename_check.go (about) 1 // Copyright 2019 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 // 5 // Taken from github.com/april1989/origin-go-tools/refactor/rename. 6 7 package source 8 9 import ( 10 "fmt" 11 "go/ast" 12 "go/token" 13 "go/types" 14 "reflect" 15 "strconv" 16 "strings" 17 "unicode" 18 19 "github.com/april1989/origin-go-tools/go/ast/astutil" 20 "github.com/april1989/origin-go-tools/refactor/satisfy" 21 ) 22 23 // errorf reports an error (e.g. conflict) and prevents file modification. 24 func (r *renamer) errorf(pos token.Pos, format string, args ...interface{}) { 25 r.hadConflicts = true 26 r.errors += fmt.Sprintf(format, args...) 27 } 28 29 // check performs safety checks of the renaming of the 'from' object to r.to. 30 func (r *renamer) check(from types.Object) { 31 if r.objsToUpdate[from] { 32 return 33 } 34 r.objsToUpdate[from] = true 35 36 // NB: order of conditions is important. 37 if from_, ok := from.(*types.PkgName); ok { 38 r.checkInFileBlock(from_) 39 } else if from_, ok := from.(*types.Label); ok { 40 r.checkLabel(from_) 41 } else if isPackageLevel(from) { 42 r.checkInPackageBlock(from) 43 } else if v, ok := from.(*types.Var); ok && v.IsField() { 44 r.checkStructField(v) 45 } else if f, ok := from.(*types.Func); ok && recv(f) != nil { 46 r.checkMethod(f) 47 } else if isLocal(from) { 48 r.checkInLocalScope(from) 49 } else { 50 r.errorf(from.Pos(), "unexpected %s object %q (please report a bug)\n", 51 objectKind(from), from) 52 } 53 } 54 55 // checkInFileBlock performs safety checks for renames of objects in the file block, 56 // i.e. imported package names. 57 func (r *renamer) checkInFileBlock(from *types.PkgName) { 58 // Check import name is not "init". 59 if r.to == "init" { 60 r.errorf(from.Pos(), "%q is not a valid imported package name", r.to) 61 } 62 63 // Check for conflicts between file and package block. 64 if prev := from.Pkg().Scope().Lookup(r.to); prev != nil { 65 r.errorf(from.Pos(), "renaming this %s %q to %q would conflict", 66 objectKind(from), from.Name(), r.to) 67 r.errorf(prev.Pos(), "\twith this package member %s", 68 objectKind(prev)) 69 return // since checkInPackageBlock would report redundant errors 70 } 71 72 // Check for conflicts in lexical scope. 73 r.checkInLexicalScope(from, r.packages[from.Pkg()]) 74 } 75 76 // checkInPackageBlock performs safety checks for renames of 77 // func/var/const/type objects in the package block. 78 func (r *renamer) checkInPackageBlock(from types.Object) { 79 // Check that there are no references to the name from another 80 // package if the renaming would make it unexported. 81 if ast.IsExported(from.Name()) && !ast.IsExported(r.to) { 82 for typ, pkg := range r.packages { 83 if typ == from.Pkg() { 84 continue 85 } 86 if id := someUse(pkg.GetTypesInfo(), from); id != nil && 87 !r.checkExport(id, typ, from) { 88 break 89 } 90 } 91 } 92 93 pkg := r.packages[from.Pkg()] 94 if pkg == nil { 95 return 96 } 97 98 // Check that in the package block, "init" is a function, and never referenced. 99 if r.to == "init" { 100 kind := objectKind(from) 101 if kind == "func" { 102 // Reject if intra-package references to it exist. 103 for id, obj := range pkg.GetTypesInfo().Uses { 104 if obj == from { 105 r.errorf(from.Pos(), 106 "renaming this func %q to %q would make it a package initializer", 107 from.Name(), r.to) 108 r.errorf(id.Pos(), "\tbut references to it exist") 109 break 110 } 111 } 112 } else { 113 r.errorf(from.Pos(), "you cannot have a %s at package level named %q", 114 kind, r.to) 115 } 116 } 117 118 // Check for conflicts between package block and all file blocks. 119 for _, f := range pkg.GetSyntax() { 120 fileScope := pkg.GetTypesInfo().Scopes[f] 121 b, prev := fileScope.LookupParent(r.to, token.NoPos) 122 if b == fileScope { 123 r.errorf(from.Pos(), "renaming this %s %q to %q would conflict", objectKind(from), from.Name(), r.to) 124 var prevPos token.Pos 125 if prev != nil { 126 prevPos = prev.Pos() 127 } 128 r.errorf(prevPos, "\twith this %s", objectKind(prev)) 129 return // since checkInPackageBlock would report redundant errors 130 } 131 } 132 133 // Check for conflicts in lexical scope. 134 if from.Exported() { 135 for _, pkg := range r.packages { 136 r.checkInLexicalScope(from, pkg) 137 } 138 } else { 139 r.checkInLexicalScope(from, pkg) 140 } 141 } 142 143 func (r *renamer) checkInLocalScope(from types.Object) { 144 pkg := r.packages[from.Pkg()] 145 r.checkInLexicalScope(from, pkg) 146 } 147 148 // checkInLexicalScope performs safety checks that a renaming does not 149 // change the lexical reference structure of the specified package. 150 // 151 // For objects in lexical scope, there are three kinds of conflicts: 152 // same-, sub-, and super-block conflicts. We will illustrate all three 153 // using this example: 154 // 155 // var x int 156 // var z int 157 // 158 // func f(y int) { 159 // print(x) 160 // print(y) 161 // } 162 // 163 // Renaming x to z encounters a SAME-BLOCK CONFLICT, because an object 164 // with the new name already exists, defined in the same lexical block 165 // as the old object. 166 // 167 // Renaming x to y encounters a SUB-BLOCK CONFLICT, because there exists 168 // a reference to x from within (what would become) a hole in its scope. 169 // The definition of y in an (inner) sub-block would cast a shadow in 170 // the scope of the renamed variable. 171 // 172 // Renaming y to x encounters a SUPER-BLOCK CONFLICT. This is the 173 // converse situation: there is an existing definition of the new name 174 // (x) in an (enclosing) super-block, and the renaming would create a 175 // hole in its scope, within which there exist references to it. The 176 // new name casts a shadow in scope of the existing definition of x in 177 // the super-block. 178 // 179 // Removing the old name (and all references to it) is always safe, and 180 // requires no checks. 181 // 182 func (r *renamer) checkInLexicalScope(from types.Object, pkg Package) { 183 b := from.Parent() // the block defining the 'from' object 184 if b != nil { 185 toBlock, to := b.LookupParent(r.to, from.Parent().End()) 186 if toBlock == b { 187 // same-block conflict 188 r.errorf(from.Pos(), "renaming this %s %q to %q", 189 objectKind(from), from.Name(), r.to) 190 r.errorf(to.Pos(), "\tconflicts with %s in same block", 191 objectKind(to)) 192 return 193 } else if toBlock != nil { 194 // Check for super-block conflict. 195 // The name r.to is defined in a superblock. 196 // Is that name referenced from within this block? 197 forEachLexicalRef(pkg, to, func(id *ast.Ident, block *types.Scope) bool { 198 _, obj := lexicalLookup(block, from.Name(), id.Pos()) 199 if obj == from { 200 // super-block conflict 201 r.errorf(from.Pos(), "renaming this %s %q to %q", 202 objectKind(from), from.Name(), r.to) 203 r.errorf(id.Pos(), "\twould shadow this reference") 204 r.errorf(to.Pos(), "\tto the %s declared here", 205 objectKind(to)) 206 return false // stop 207 } 208 return true 209 }) 210 } 211 } 212 // Check for sub-block conflict. 213 // Is there an intervening definition of r.to between 214 // the block defining 'from' and some reference to it? 215 forEachLexicalRef(pkg, from, func(id *ast.Ident, block *types.Scope) bool { 216 // Find the block that defines the found reference. 217 // It may be an ancestor. 218 fromBlock, _ := lexicalLookup(block, from.Name(), id.Pos()) 219 220 // See what r.to would resolve to in the same scope. 221 toBlock, to := lexicalLookup(block, r.to, id.Pos()) 222 if to != nil { 223 // sub-block conflict 224 if deeper(toBlock, fromBlock) { 225 r.errorf(from.Pos(), "renaming this %s %q to %q", 226 objectKind(from), from.Name(), r.to) 227 r.errorf(id.Pos(), "\twould cause this reference to become shadowed") 228 r.errorf(to.Pos(), "\tby this intervening %s definition", 229 objectKind(to)) 230 return false // stop 231 } 232 } 233 return true 234 }) 235 236 // Renaming a type that is used as an embedded field 237 // requires renaming the field too. e.g. 238 // type T int // if we rename this to U.. 239 // var s struct {T} 240 // print(s.T) // ...this must change too 241 if _, ok := from.(*types.TypeName); ok { 242 for id, obj := range pkg.GetTypesInfo().Uses { 243 if obj == from { 244 if field := pkg.GetTypesInfo().Defs[id]; field != nil { 245 r.check(field) 246 } 247 } 248 } 249 } 250 } 251 252 // lexicalLookup is like (*types.Scope).LookupParent but respects the 253 // environment visible at pos. It assumes the relative position 254 // information is correct with each file. 255 func lexicalLookup(block *types.Scope, name string, pos token.Pos) (*types.Scope, types.Object) { 256 for b := block; b != nil; b = b.Parent() { 257 obj := b.Lookup(name) 258 // The scope of a package-level object is the entire package, 259 // so ignore pos in that case. 260 // No analogous clause is needed for file-level objects 261 // since no reference can appear before an import decl. 262 if obj == nil || obj.Pkg() == nil { 263 continue 264 } 265 if b == obj.Pkg().Scope() || obj.Pos() < pos { 266 return b, obj 267 } 268 } 269 return nil, nil 270 } 271 272 // deeper reports whether block x is lexically deeper than y. 273 func deeper(x, y *types.Scope) bool { 274 if x == y || x == nil { 275 return false 276 } else if y == nil { 277 return true 278 } else { 279 return deeper(x.Parent(), y.Parent()) 280 } 281 } 282 283 // forEachLexicalRef calls fn(id, block) for each identifier id in package 284 // pkg that is a reference to obj in lexical scope. block is the 285 // lexical block enclosing the reference. If fn returns false the 286 // iteration is terminated and findLexicalRefs returns false. 287 func forEachLexicalRef(pkg Package, obj types.Object, fn func(id *ast.Ident, block *types.Scope) bool) bool { 288 ok := true 289 var stack []ast.Node 290 291 var visit func(n ast.Node) bool 292 visit = func(n ast.Node) bool { 293 if n == nil { 294 stack = stack[:len(stack)-1] // pop 295 return false 296 } 297 if !ok { 298 return false // bail out 299 } 300 301 stack = append(stack, n) // push 302 switch n := n.(type) { 303 case *ast.Ident: 304 if pkg.GetTypesInfo().Uses[n] == obj { 305 block := enclosingBlock(pkg.GetTypesInfo(), stack) 306 if !fn(n, block) { 307 ok = false 308 } 309 } 310 return visit(nil) // pop stack 311 312 case *ast.SelectorExpr: 313 // don't visit n.Sel 314 ast.Inspect(n.X, visit) 315 return visit(nil) // pop stack, don't descend 316 317 case *ast.CompositeLit: 318 // Handle recursion ourselves for struct literals 319 // so we don't visit field identifiers. 320 tv, ok := pkg.GetTypesInfo().Types[n] 321 if !ok { 322 return visit(nil) // pop stack, don't descend 323 } 324 if _, ok := deref(tv.Type).Underlying().(*types.Struct); ok { 325 if n.Type != nil { 326 ast.Inspect(n.Type, visit) 327 } 328 for _, elt := range n.Elts { 329 if kv, ok := elt.(*ast.KeyValueExpr); ok { 330 ast.Inspect(kv.Value, visit) 331 } else { 332 ast.Inspect(elt, visit) 333 } 334 } 335 return visit(nil) // pop stack, don't descend 336 } 337 } 338 return true 339 } 340 341 for _, f := range pkg.GetSyntax() { 342 ast.Inspect(f, visit) 343 if len(stack) != 0 { 344 panic(stack) 345 } 346 if !ok { 347 break 348 } 349 } 350 return ok 351 } 352 353 // enclosingBlock returns the innermost block enclosing the specified 354 // AST node, specified in the form of a path from the root of the file, 355 // [file...n]. 356 func enclosingBlock(info *types.Info, stack []ast.Node) *types.Scope { 357 for i := range stack { 358 n := stack[len(stack)-1-i] 359 // For some reason, go/types always associates a 360 // function's scope with its FuncType. 361 // TODO(adonovan): feature or a bug? 362 switch f := n.(type) { 363 case *ast.FuncDecl: 364 n = f.Type 365 case *ast.FuncLit: 366 n = f.Type 367 } 368 if b := info.Scopes[n]; b != nil { 369 return b 370 } 371 } 372 panic("no Scope for *ast.File") 373 } 374 375 func (r *renamer) checkLabel(label *types.Label) { 376 // Check there are no identical labels in the function's label block. 377 // (Label blocks don't nest, so this is easy.) 378 if prev := label.Parent().Lookup(r.to); prev != nil { 379 r.errorf(label.Pos(), "renaming this label %q to %q", label.Name(), prev.Name()) 380 r.errorf(prev.Pos(), "\twould conflict with this one") 381 } 382 } 383 384 // checkStructField checks that the field renaming will not cause 385 // conflicts at its declaration, or ambiguity or changes to any selection. 386 func (r *renamer) checkStructField(from *types.Var) { 387 // Check that the struct declaration is free of field conflicts, 388 // and field/method conflicts. 389 390 // go/types offers no easy way to get from a field (or interface 391 // method) to its declaring struct (or interface), so we must 392 // ascend the AST. 393 pkg, path, _ := pathEnclosingInterval(r.fset, r.packages[from.Pkg()], from.Pos(), from.Pos()) 394 if pkg == nil || path == nil { 395 return 396 } 397 // path matches this pattern: 398 // [Ident SelectorExpr? StarExpr? Field FieldList StructType ParenExpr* ... File] 399 400 // Ascend to FieldList. 401 var i int 402 for { 403 if _, ok := path[i].(*ast.FieldList); ok { 404 break 405 } 406 i++ 407 } 408 i++ 409 tStruct := path[i].(*ast.StructType) 410 i++ 411 // Ascend past parens (unlikely). 412 for { 413 _, ok := path[i].(*ast.ParenExpr) 414 if !ok { 415 break 416 } 417 i++ 418 } 419 if spec, ok := path[i].(*ast.TypeSpec); ok { 420 // This struct is also a named type. 421 // We must check for direct (non-promoted) field/field 422 // and method/field conflicts. 423 named := pkg.GetTypesInfo().Defs[spec.Name].Type() 424 prev, indices, _ := types.LookupFieldOrMethod(named, true, pkg.GetTypes(), r.to) 425 if len(indices) == 1 { 426 r.errorf(from.Pos(), "renaming this field %q to %q", 427 from.Name(), r.to) 428 r.errorf(prev.Pos(), "\twould conflict with this %s", 429 objectKind(prev)) 430 return // skip checkSelections to avoid redundant errors 431 } 432 } else { 433 // This struct is not a named type. 434 // We need only check for direct (non-promoted) field/field conflicts. 435 T := pkg.GetTypesInfo().Types[tStruct].Type.Underlying().(*types.Struct) 436 for i := 0; i < T.NumFields(); i++ { 437 if prev := T.Field(i); prev.Name() == r.to { 438 r.errorf(from.Pos(), "renaming this field %q to %q", 439 from.Name(), r.to) 440 r.errorf(prev.Pos(), "\twould conflict with this field") 441 return // skip checkSelections to avoid redundant errors 442 } 443 } 444 } 445 446 // Renaming an anonymous field requires renaming the type too. e.g. 447 // print(s.T) // if we rename T to U, 448 // type T int // this and 449 // var s struct {T} // this must change too. 450 if from.Anonymous() { 451 if named, ok := from.Type().(*types.Named); ok { 452 r.check(named.Obj()) 453 } else if named, ok := deref(from.Type()).(*types.Named); ok { 454 r.check(named.Obj()) 455 } 456 } 457 458 // Check integrity of existing (field and method) selections. 459 r.checkSelections(from) 460 } 461 462 // checkSelection checks that all uses and selections that resolve to 463 // the specified object would continue to do so after the renaming. 464 func (r *renamer) checkSelections(from types.Object) { 465 for typ, pkg := range r.packages { 466 if id := someUse(pkg.GetTypesInfo(), from); id != nil { 467 if !r.checkExport(id, typ, from) { 468 return 469 } 470 } 471 472 for syntax, sel := range pkg.GetTypesInfo().Selections { 473 // There may be extant selections of only the old 474 // name or only the new name, so we must check both. 475 // (If neither, the renaming is sound.) 476 // 477 // In both cases, we wish to compare the lengths 478 // of the implicit field path (Selection.Index) 479 // to see if the renaming would change it. 480 // 481 // If a selection that resolves to 'from', when renamed, 482 // would yield a path of the same or shorter length, 483 // this indicates ambiguity or a changed referent, 484 // analogous to same- or sub-block lexical conflict. 485 // 486 // If a selection using the name 'to' would 487 // yield a path of the same or shorter length, 488 // this indicates ambiguity or shadowing, 489 // analogous to same- or super-block lexical conflict. 490 491 // TODO(adonovan): fix: derive from Types[syntax.X].Mode 492 // TODO(adonovan): test with pointer, value, addressable value. 493 isAddressable := true 494 495 if sel.Obj() == from { 496 if obj, indices, _ := types.LookupFieldOrMethod(sel.Recv(), isAddressable, from.Pkg(), r.to); obj != nil { 497 // Renaming this existing selection of 498 // 'from' may block access to an existing 499 // type member named 'to'. 500 delta := len(indices) - len(sel.Index()) 501 if delta > 0 { 502 continue // no ambiguity 503 } 504 r.selectionConflict(from, delta, syntax, obj) 505 return 506 } 507 } else if sel.Obj().Name() == r.to { 508 if obj, indices, _ := types.LookupFieldOrMethod(sel.Recv(), isAddressable, from.Pkg(), from.Name()); obj == from { 509 // Renaming 'from' may cause this existing 510 // selection of the name 'to' to change 511 // its meaning. 512 delta := len(indices) - len(sel.Index()) 513 if delta > 0 { 514 continue // no ambiguity 515 } 516 r.selectionConflict(from, -delta, syntax, sel.Obj()) 517 return 518 } 519 } 520 } 521 } 522 } 523 524 func (r *renamer) selectionConflict(from types.Object, delta int, syntax *ast.SelectorExpr, obj types.Object) { 525 r.errorf(from.Pos(), "renaming this %s %q to %q", 526 objectKind(from), from.Name(), r.to) 527 528 switch { 529 case delta < 0: 530 // analogous to sub-block conflict 531 r.errorf(syntax.Sel.Pos(), 532 "\twould change the referent of this selection") 533 r.errorf(obj.Pos(), "\tof this %s", objectKind(obj)) 534 case delta == 0: 535 // analogous to same-block conflict 536 r.errorf(syntax.Sel.Pos(), 537 "\twould make this reference ambiguous") 538 r.errorf(obj.Pos(), "\twith this %s", objectKind(obj)) 539 case delta > 0: 540 // analogous to super-block conflict 541 r.errorf(syntax.Sel.Pos(), 542 "\twould shadow this selection") 543 r.errorf(obj.Pos(), "\tof the %s declared here", 544 objectKind(obj)) 545 } 546 } 547 548 // checkMethod performs safety checks for renaming a method. 549 // There are three hazards: 550 // - declaration conflicts 551 // - selection ambiguity/changes 552 // - entailed renamings of assignable concrete/interface types. 553 // We reject renamings initiated at concrete methods if it would 554 // change the assignability relation. For renamings of abstract 555 // methods, we rename all methods transitively coupled to it via 556 // assignability. 557 func (r *renamer) checkMethod(from *types.Func) { 558 // e.g. error.Error 559 if from.Pkg() == nil { 560 r.errorf(from.Pos(), "you cannot rename built-in method %s", from) 561 return 562 } 563 564 // ASSIGNABILITY: We reject renamings of concrete methods that 565 // would break a 'satisfy' constraint; but renamings of abstract 566 // methods are allowed to proceed, and we rename affected 567 // concrete and abstract methods as necessary. It is the 568 // initial method that determines the policy. 569 570 // Check for conflict at point of declaration. 571 // Check to ensure preservation of assignability requirements. 572 R := recv(from).Type() 573 if isInterface(R) { 574 // Abstract method 575 576 // declaration 577 prev, _, _ := types.LookupFieldOrMethod(R, false, from.Pkg(), r.to) 578 if prev != nil { 579 r.errorf(from.Pos(), "renaming this interface method %q to %q", 580 from.Name(), r.to) 581 r.errorf(prev.Pos(), "\twould conflict with this method") 582 return 583 } 584 585 // Check all interfaces that embed this one for 586 // declaration conflicts too. 587 for _, pkg := range r.packages { 588 // Start with named interface types (better errors) 589 for _, obj := range pkg.GetTypesInfo().Defs { 590 if obj, ok := obj.(*types.TypeName); ok && isInterface(obj.Type()) { 591 f, _, _ := types.LookupFieldOrMethod( 592 obj.Type(), false, from.Pkg(), from.Name()) 593 if f == nil { 594 continue 595 } 596 t, _, _ := types.LookupFieldOrMethod( 597 obj.Type(), false, from.Pkg(), r.to) 598 if t == nil { 599 continue 600 } 601 r.errorf(from.Pos(), "renaming this interface method %q to %q", 602 from.Name(), r.to) 603 r.errorf(t.Pos(), "\twould conflict with this method") 604 r.errorf(obj.Pos(), "\tin named interface type %q", obj.Name()) 605 } 606 } 607 608 // Now look at all literal interface types (includes named ones again). 609 for e, tv := range pkg.GetTypesInfo().Types { 610 if e, ok := e.(*ast.InterfaceType); ok { 611 _ = e 612 _ = tv.Type.(*types.Interface) 613 // TODO(adonovan): implement same check as above. 614 } 615 } 616 } 617 618 // assignability 619 // 620 // Find the set of concrete or abstract methods directly 621 // coupled to abstract method 'from' by some 622 // satisfy.Constraint, and rename them too. 623 for key := range r.satisfy() { 624 // key = (lhs, rhs) where lhs is always an interface. 625 626 lsel := r.msets.MethodSet(key.LHS).Lookup(from.Pkg(), from.Name()) 627 if lsel == nil { 628 continue 629 } 630 rmethods := r.msets.MethodSet(key.RHS) 631 rsel := rmethods.Lookup(from.Pkg(), from.Name()) 632 if rsel == nil { 633 continue 634 } 635 636 // If both sides have a method of this name, 637 // and one of them is m, the other must be coupled. 638 var coupled *types.Func 639 switch from { 640 case lsel.Obj(): 641 coupled = rsel.Obj().(*types.Func) 642 case rsel.Obj(): 643 coupled = lsel.Obj().(*types.Func) 644 default: 645 continue 646 } 647 648 // We must treat concrete-to-interface 649 // constraints like an implicit selection C.f of 650 // each interface method I.f, and check that the 651 // renaming leaves the selection unchanged and 652 // unambiguous. 653 // 654 // Fun fact: the implicit selection of C.f 655 // type I interface{f()} 656 // type C struct{I} 657 // func (C) g() 658 // var _ I = C{} // here 659 // yields abstract method I.f. This can make error 660 // messages less than obvious. 661 // 662 if !isInterface(key.RHS) { 663 // The logic below was derived from checkSelections. 664 665 rtosel := rmethods.Lookup(from.Pkg(), r.to) 666 if rtosel != nil { 667 rto := rtosel.Obj().(*types.Func) 668 delta := len(rsel.Index()) - len(rtosel.Index()) 669 if delta < 0 { 670 continue // no ambiguity 671 } 672 673 // TODO(adonovan): record the constraint's position. 674 keyPos := token.NoPos 675 676 r.errorf(from.Pos(), "renaming this method %q to %q", 677 from.Name(), r.to) 678 if delta == 0 { 679 // analogous to same-block conflict 680 r.errorf(keyPos, "\twould make the %s method of %s invoked via interface %s ambiguous", 681 r.to, key.RHS, key.LHS) 682 r.errorf(rto.Pos(), "\twith (%s).%s", 683 recv(rto).Type(), r.to) 684 } else { 685 // analogous to super-block conflict 686 r.errorf(keyPos, "\twould change the %s method of %s invoked via interface %s", 687 r.to, key.RHS, key.LHS) 688 r.errorf(coupled.Pos(), "\tfrom (%s).%s", 689 recv(coupled).Type(), r.to) 690 r.errorf(rto.Pos(), "\tto (%s).%s", 691 recv(rto).Type(), r.to) 692 } 693 return // one error is enough 694 } 695 } 696 697 if !r.changeMethods { 698 // This should be unreachable. 699 r.errorf(from.Pos(), "internal error: during renaming of abstract method %s", from) 700 r.errorf(coupled.Pos(), "\tchangedMethods=false, coupled method=%s", coupled) 701 r.errorf(from.Pos(), "\tPlease file a bug report") 702 return 703 } 704 705 // Rename the coupled method to preserve assignability. 706 r.check(coupled) 707 } 708 } else { 709 // Concrete method 710 711 // declaration 712 prev, indices, _ := types.LookupFieldOrMethod(R, true, from.Pkg(), r.to) 713 if prev != nil && len(indices) == 1 { 714 r.errorf(from.Pos(), "renaming this method %q to %q", 715 from.Name(), r.to) 716 r.errorf(prev.Pos(), "\twould conflict with this %s", 717 objectKind(prev)) 718 return 719 } 720 721 // assignability 722 // 723 // Find the set of abstract methods coupled to concrete 724 // method 'from' by some satisfy.Constraint, and rename 725 // them too. 726 // 727 // Coupling may be indirect, e.g. I.f <-> C.f via type D. 728 // 729 // type I interface {f()} 730 // type C int 731 // type (C) f() 732 // type D struct{C} 733 // var _ I = D{} 734 // 735 for key := range r.satisfy() { 736 // key = (lhs, rhs) where lhs is always an interface. 737 if isInterface(key.RHS) { 738 continue 739 } 740 rsel := r.msets.MethodSet(key.RHS).Lookup(from.Pkg(), from.Name()) 741 if rsel == nil || rsel.Obj() != from { 742 continue // rhs does not have the method 743 } 744 lsel := r.msets.MethodSet(key.LHS).Lookup(from.Pkg(), from.Name()) 745 if lsel == nil { 746 continue 747 } 748 imeth := lsel.Obj().(*types.Func) 749 750 // imeth is the abstract method (e.g. I.f) 751 // and key.RHS is the concrete coupling type (e.g. D). 752 if !r.changeMethods { 753 r.errorf(from.Pos(), "renaming this method %q to %q", 754 from.Name(), r.to) 755 var pos token.Pos 756 var iface string 757 758 I := recv(imeth).Type() 759 if named, ok := I.(*types.Named); ok { 760 pos = named.Obj().Pos() 761 iface = "interface " + named.Obj().Name() 762 } else { 763 pos = from.Pos() 764 iface = I.String() 765 } 766 r.errorf(pos, "\twould make %s no longer assignable to %s", 767 key.RHS, iface) 768 r.errorf(imeth.Pos(), "\t(rename %s.%s if you intend to change both types)", 769 I, from.Name()) 770 return // one error is enough 771 } 772 773 // Rename the coupled interface method to preserve assignability. 774 r.check(imeth) 775 } 776 } 777 778 // Check integrity of existing (field and method) selections. 779 // We skip this if there were errors above, to avoid redundant errors. 780 r.checkSelections(from) 781 } 782 783 func (r *renamer) checkExport(id *ast.Ident, pkg *types.Package, from types.Object) bool { 784 // Reject cross-package references if r.to is unexported. 785 // (Such references may be qualified identifiers or field/method 786 // selections.) 787 if !ast.IsExported(r.to) && pkg != from.Pkg() { 788 r.errorf(from.Pos(), 789 "renaming %q to %q would make it unexported", 790 from.Name(), r.to) 791 r.errorf(id.Pos(), "\tbreaking references from packages such as %q", 792 pkg.Path()) 793 return false 794 } 795 return true 796 } 797 798 // satisfy returns the set of interface satisfaction constraints. 799 func (r *renamer) satisfy() map[satisfy.Constraint]bool { 800 if r.satisfyConstraints == nil { 801 // Compute on demand: it's expensive. 802 var f satisfy.Finder 803 for _, pkg := range r.packages { 804 // From satisfy.Finder documentation: 805 // 806 // The package must be free of type errors, and 807 // info.{Defs,Uses,Selections,Types} must have been populated by the 808 // type-checker. 809 // 810 // Only proceed if all packages have no errors. 811 if errs := pkg.GetErrors(); len(errs) > 0 { 812 r.errorf(token.NoPos, // we don't have a position for this error. 813 "renaming %q to %q not possible because %q has errors", 814 r.from, r.to, pkg.PkgPath()) 815 return nil 816 } 817 f.Find(pkg.GetTypesInfo(), pkg.GetSyntax()) 818 } 819 r.satisfyConstraints = f.Result 820 } 821 return r.satisfyConstraints 822 } 823 824 // -- helpers ---------------------------------------------------------- 825 826 // recv returns the method's receiver. 827 func recv(meth *types.Func) *types.Var { 828 return meth.Type().(*types.Signature).Recv() 829 } 830 831 // someUse returns an arbitrary use of obj within info. 832 func someUse(info *types.Info, obj types.Object) *ast.Ident { 833 for id, o := range info.Uses { 834 if o == obj { 835 return id 836 } 837 } 838 return nil 839 } 840 841 // pathEnclosingInterval returns the Package and ast.Node that 842 // contain source interval [start, end), and all the node's ancestors 843 // up to the AST root. It searches all ast.Files of all packages. 844 // exact is defined as for astutil.PathEnclosingInterval. 845 // 846 // The zero value is returned if not found. 847 // 848 func pathEnclosingInterval(fset *token.FileSet, pkg Package, start, end token.Pos) (resPkg Package, path []ast.Node, exact bool) { 849 pkgs := []Package{pkg} 850 for _, f := range pkg.GetSyntax() { 851 for _, imp := range f.Imports { 852 if imp == nil { 853 continue 854 } 855 importPath, err := strconv.Unquote(imp.Path.Value) 856 if err != nil { 857 continue 858 } 859 importPkg, err := pkg.GetImport(importPath) 860 if err != nil { 861 return nil, nil, false 862 } 863 pkgs = append(pkgs, importPkg) 864 } 865 } 866 for _, p := range pkgs { 867 for _, f := range p.GetSyntax() { 868 if f.Pos() == token.NoPos { 869 // This can happen if the parser saw 870 // too many errors and bailed out. 871 // (Use parser.AllErrors to prevent that.) 872 continue 873 } 874 if !tokenFileContainsPos(fset.File(f.Pos()), start) { 875 continue 876 } 877 if path, exact := astutil.PathEnclosingInterval(f, start, end); path != nil { 878 return pkg, path, exact 879 } 880 } 881 } 882 return nil, nil, false 883 } 884 885 // TODO(adonovan): make this a method: func (*token.File) Contains(token.Pos) 886 func tokenFileContainsPos(f *token.File, pos token.Pos) bool { 887 p := int(pos) 888 base := f.Base() 889 return base <= p && p < base+f.Size() 890 } 891 892 func objectKind(obj types.Object) string { 893 switch obj := obj.(type) { 894 case *types.PkgName: 895 return "imported package name" 896 case *types.TypeName: 897 return "type" 898 case *types.Var: 899 if obj.IsField() { 900 return "field" 901 } 902 case *types.Func: 903 if obj.Type().(*types.Signature).Recv() != nil { 904 return "method" 905 } 906 } 907 // label, func, var, const 908 return strings.ToLower(strings.TrimPrefix(reflect.TypeOf(obj).String(), "*types.")) 909 } 910 911 // NB: for renamings, blank is not considered valid. 912 func isValidIdentifier(id string) bool { 913 if id == "" || id == "_" { 914 return false 915 } 916 for i, r := range id { 917 if !isLetter(r) && (i == 0 || !isDigit(r)) { 918 return false 919 } 920 } 921 return token.Lookup(id) == token.IDENT 922 } 923 924 // isLocal reports whether obj is local to some function. 925 // Precondition: not a struct field or interface method. 926 func isLocal(obj types.Object) bool { 927 // [... 5=stmt 4=func 3=file 2=pkg 1=universe] 928 var depth int 929 for scope := obj.Parent(); scope != nil; scope = scope.Parent() { 930 depth++ 931 } 932 return depth >= 4 933 } 934 935 func isPackageLevel(obj types.Object) bool { 936 return obj.Pkg().Scope().Lookup(obj.Name()) == obj 937 } 938 939 func isInterface(T types.Type) bool { 940 return T != nil && types.IsInterface(T) 941 } 942 943 // -- Plundered from go/scanner: --------------------------------------- 944 945 func isLetter(ch rune) bool { 946 return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_' || ch >= 0x80 && unicode.IsLetter(ch) 947 } 948 949 func isDigit(ch rune) bool { 950 return '0' <= ch && ch <= '9' || ch >= 0x80 && unicode.IsDigit(ch) 951 }