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[dev.typeparams] cmd/compile/internal/types2: report unused packages in source order

1) Rather than map-iterate through all file scopes and collect unused
   packages, collect all imports in the Checker.imports list so that
   errors are reported in source order.

2) From cmd/compile, borrow the idea of a "dotImportRefs" map to map
   dot-imported objects to the package they were dot-imported through
   (we call the map "dotImportMap").

3) From cmd/compile, borrow the "pkgnotused" function
   (called Checker.errorUnusedPkg in this code) and clean up
   unused package error reporting.

4) Adjust unused package error message to match compiler message exactly.

5) Enable one more excluded test case in test/run.go.

Change-Id: I4e4e55512a6043a7fd54f576c7441e3dd4077d6f
Reviewed-on: https://go-review.googlesource.com/c/go/+/287072
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
Robert Griesemer 2021-01-26 12:08:18 -08:00
parent 08a598f8c1
commit 217a461f56
6 changed files with 62 additions and 74 deletions

View File

@ -74,6 +74,12 @@ type importKey struct {
path, dir string
}
// A dotImportKey describes a dot-imported object in the given scope.
type dotImportKey struct {
scope *Scope
obj Object
}
// A Checker maintains the state of the type checker.
// It must be created with NewChecker.
type Checker struct {
@ -92,8 +98,9 @@ type Checker struct {
// information collected during type-checking of a set of package files
// (initialized by Files, valid only for the duration of check.Files;
// maps and lists are allocated on demand)
files []*syntax.File // package files
unusedDotImports map[*Scope]map[*Package]syntax.Pos // positions of unused dot-imported packages for each file scope
files []*syntax.File // list of package files
imports []*PkgName // list of imported packages
dotImportMap map[dotImportKey]*PkgName // maps dot-imported objects to the package they were dot-imported through
firstErr error // first error encountered
methods map[*TypeName][]*Func // maps package scope type names to associated non-blank (non-interface) methods
@ -110,22 +117,6 @@ type Checker struct {
indent int // indentation for tracing
}
// addUnusedImport adds the position of a dot-imported package
// pkg to the map of dot imports for the given file scope.
func (check *Checker) addUnusedDotImport(scope *Scope, pkg *Package, pos syntax.Pos) {
mm := check.unusedDotImports
if mm == nil {
mm = make(map[*Scope]map[*Package]syntax.Pos)
check.unusedDotImports = mm
}
m := mm[scope]
if m == nil {
m = make(map[*Package]syntax.Pos)
mm[scope] = m
}
m[pkg] = pos
}
// addDeclDep adds the dependency edge (check.decl -> to) if check.decl exists
func (check *Checker) addDeclDep(to Object) {
from := check.decl
@ -209,7 +200,8 @@ func NewChecker(conf *Config, pkg *Package, info *Info) *Checker {
func (check *Checker) initFiles(files []*syntax.File) {
// start with a clean slate (check.Files may be called multiple times)
check.files = nil
check.unusedDotImports = nil
check.imports = nil
check.dotImportMap = nil
check.firstErr = nil
check.methods = nil
@ -291,6 +283,9 @@ func (check *Checker) checkFiles(files []*syntax.File) (err error) {
print("== unusedImports ==")
check.unusedImports()
}
// no longer needed - release memory
check.imports = nil
check.dotImportMap = nil
print("== recordUntyped ==")
check.recordUntyped()
@ -301,6 +296,9 @@ func (check *Checker) checkFiles(files []*syntax.File) (err error) {
}
check.pkg.complete = true
// TODO(gri) There's more memory we should release at this point.
return
}

View File

@ -273,21 +273,26 @@ func (check *Checker) collectObjects() {
}
}
obj := NewPkgName(s.Pos(), pkg, name, imp)
pkgName := NewPkgName(s.Pos(), pkg, name, imp)
if s.LocalPkgName != nil {
// in a dot-import, the dot represents the package
check.recordDef(s.LocalPkgName, obj)
check.recordDef(s.LocalPkgName, pkgName)
} else {
check.recordImplicit(s, obj)
check.recordImplicit(s, pkgName)
}
if path == "C" {
// match cmd/compile (not prescribed by spec)
obj.used = true
pkgName.used = true
}
// add import to file scope
check.imports = append(check.imports, pkgName)
if name == "." {
// dot-import
if check.dotImportMap == nil {
check.dotImportMap = make(map[dotImportKey]*PkgName)
}
// merge imported scope with file scope
for _, obj := range imp.scope.elems {
// A package scope may contain non-exported objects,
@ -301,16 +306,15 @@ func (check *Checker) collectObjects() {
if alt := fileScope.Insert(obj); alt != nil {
check.errorf(s.LocalPkgName, "%s redeclared in this block", obj.Name())
check.reportAltDecl(alt)
} else {
check.dotImportMap[dotImportKey{fileScope, obj}] = pkgName
}
}
}
// add position to set of dot-import positions for this file
// (this is only needed for "imported but not used" errors)
check.addUnusedDotImport(fileScope, imp, s.Pos())
} else {
// declare imported package object in file scope
// (no need to provide s.LocalPkgName since we called check.recordDef earlier)
check.declare(fileScope, nil, obj, nopos)
check.declare(fileScope, nil, pkgName, nopos)
}
case *syntax.ConstDecl:
@ -673,51 +677,38 @@ func (check *Checker) unusedImports() {
// any of its exported identifiers. To import a package solely for its side-effects
// (initialization), use the blank identifier as explicit package name."
// check use of regular imported packages
for _, scope := range check.pkg.scope.children /* file scopes */ {
for _, obj := range scope.elems {
if obj, ok := obj.(*PkgName); ok {
// Unused "blank imports" are automatically ignored
// since _ identifiers are not entered into scopes.
if !obj.used {
path := obj.imported.path
base := pkgName(path)
if obj.name == base {
if check.conf.CompilerErrorMessages {
check.softErrorf(obj.pos, "%q imported and not used", path)
} else {
check.softErrorf(obj.pos, "%q imported but not used", path)
}
} else {
if check.conf.CompilerErrorMessages {
check.softErrorf(obj.pos, "%q imported and not used as %s", path, obj.name)
} else {
check.softErrorf(obj.pos, "%q imported but not used as %s", path, obj.name)
}
}
}
}
}
}
// check use of dot-imported packages
for _, unusedDotImports := range check.unusedDotImports {
for pkg, pos := range unusedDotImports {
if check.conf.CompilerErrorMessages {
check.softErrorf(pos, "%q imported and not used", pkg.path)
} else {
check.softErrorf(pos, "%q imported but not used", pkg.path)
}
for _, obj := range check.imports {
if !obj.used && obj.name != "_" {
check.errorUnusedPkg(obj)
}
}
}
// pkgName returns the package name (last element) of an import path.
func pkgName(path string) string {
if i := strings.LastIndex(path, "/"); i >= 0 {
path = path[i+1:]
func (check *Checker) errorUnusedPkg(obj *PkgName) {
// If the package was imported with a name other than the final
// import path element, show it explicitly in the error message.
// Note that this handles both renamed imports and imports of
// packages containing unconventional package declarations.
// Note that this uses / always, even on Windows, because Go import
// paths always use forward slashes.
path := obj.imported.path
elem := path
if i := strings.LastIndex(elem, "/"); i >= 0 {
elem = elem[i+1:]
}
if obj.name == "" || obj.name == "." || obj.name == elem {
if check.conf.CompilerErrorMessages {
check.softErrorf(obj, "imported and not used: %q", path)
} else {
check.softErrorf(obj, "%q imported but not used", path)
}
} else {
if check.conf.CompilerErrorMessages {
check.softErrorf(obj, "imported and not used: %q as %s", path, obj.name)
} else {
check.softErrorf(obj, "%q imported but not used as %s", path, obj.name)
}
}
return path
}
// dir makes a good-faith attempt to return the directory

View File

@ -8,7 +8,7 @@ import "math"
import m "math"
import . "testing" // declares T in file scope
import . /* ERROR "imported but not used" */ "unsafe"
import . /* ERROR .unsafe. imported but not used */ "unsafe"
import . "fmt" // declares Println in file scope
import (

View File

@ -4,7 +4,7 @@
package importdecl1
import . /* ERROR "imported but not used" */ "unsafe"
import . /* ERROR .unsafe. imported but not used */ "unsafe"
type B interface {
A

View File

@ -56,12 +56,12 @@ func (check *Checker) ident(x *operand, e *syntax.Name, def *Named, wantType boo
}
assert(typ != nil)
// The object may be dot-imported: If so, remove its package from
// the map of unused dot imports for the respective file scope.
// The object may have been dot-imported.
// If so, mark the respective package as used.
// (This code is only needed for dot-imports. Without them,
// we only have to mark variables, see *Var case below).
if pkg := obj.Pkg(); pkg != check.pkg && pkg != nil {
delete(check.unusedDotImports[scope], pkg)
if pkgName := check.dotImportMap[dotImportKey{scope, obj}]; pkgName != nil {
pkgName.used = true
}
switch obj := obj.(type) {

View File

@ -1956,7 +1956,6 @@ var excluded = map[string]bool{
"fixedbugs/issue18331.go": true, // missing error about misuse of //go:noescape (irgen needs code from noder)
"fixedbugs/issue18393.go": true, // types2 not run after syntax errors
"fixedbugs/issue19012.go": true, // multiple errors on same line
"fixedbugs/issue20298.go": true, // types2 non-deterministically reports unused imports
"fixedbugs/issue20233.go": true, // types2 reports two instead of one error (pref: compiler)
"fixedbugs/issue20245.go": true, // types2 reports two instead of one error (pref: compiler)
"fixedbugs/issue20250.go": true, // correct diagnostics, but different lines (probably irgen's fault)