"go/ast"
"go/constant"
"go/token"
+ "internal/goversion"
. "internal/types/errors"
)
+// nopos indicates an unknown position
+var nopos token.Pos
+
// debugging/development support
const debug = false // leave on during development
}
// A Checker maintains the state of the type checker.
-// It must be created with NewChecker.
+// It must be created with [NewChecker].
type Checker struct {
// package information
// (initialized by NewChecker, valid for the life-time of checker)
pkg *Package
*Info
version version // accepted language version
+ posVers map[token.Pos]version // maps file start positions to versions (may be nil)
nextID uint64 // unique Id for type parameters (first valid Id is 1)
objMap map[Object]*declInfo // maps package-level objects and (non-interface) methods to declaration info
impMap map[importKey]*Package // maps (import path, source directory) to (complete or fake) package
// isBrokenAlias reports whether alias doesn't have a determined type yet.
func (check *Checker) isBrokenAlias(alias *TypeName) bool {
- return alias.typ == Typ[Invalid] && check.brokenAliases[alias]
+ return !isValid(alias.typ) && check.brokenAliases[alias]
}
func (check *Checker) rememberUntyped(e ast.Expr, lhs bool, mode operandMode, typ *Basic, val constant.Value) {
check.cleaners = append(check.cleaners, c)
}
-// NewChecker returns a new Checker instance for a given package.
-// Package files may be added incrementally via checker.Files.
+// NewChecker returns a new [Checker] instance for a given package.
+// [Package] files may be added incrementally via checker.Files.
func NewChecker(conf *Config, fset *token.FileSet, pkg *Package, info *Info) *Checker {
// make sure we have a configuration
if conf == nil {
info = new(Info)
}
- version, err := parseGoVersion(conf.GoVersion)
- if err != nil {
- panic(fmt.Sprintf("invalid Go version %q (%v)", conf.GoVersion, err))
- }
+ // Note: clients may call NewChecker with the Unsafe package, which is
+ // globally shared and must not be mutated. Therefore NewChecker must not
+ // mutate *pkg.
+ //
+ // (previously, pkg.goVersion was mutated here: go.dev/issue/61212)
return &Checker{
- conf: conf,
- ctxt: conf.Context,
- fset: fset,
- pkg: pkg,
- Info: info,
- version: version,
- objMap: make(map[Object]*declInfo),
- impMap: make(map[importKey]*Package),
+ conf: conf,
+ ctxt: conf.Context,
+ fset: fset,
+ pkg: pkg,
+ Info: info,
+ objMap: make(map[Object]*declInfo),
+ impMap: make(map[importKey]*Package),
}
}
// ignore this file
}
}
+
+ // collect file versions
+ for _, file := range check.files {
+ check.recordFileVersion(file, check.conf.GoVersion)
+ if v, _ := parseGoVersion(file.GoVersion); v.major > 0 {
+ if v.equal(check.version) {
+ continue
+ }
+ // Go 1.21 introduced the feature of setting the go.mod
+ // go line to an early version of Go and allowing //go:build lines
+ // to “upgrade” the Go version in a given file.
+ // We can do that backwards compatibly.
+ // Go 1.21 also introduced the feature of allowing //go:build lines
+ // to “downgrade” the Go version in a given file.
+ // That can't be done compatibly in general, since before the
+ // build lines were ignored and code got the module's Go version.
+ // To work around this, downgrades are only allowed when the
+ // module's Go version is Go 1.21 or later.
+ // If there is no check.version, then we don't really know what Go version to apply.
+ // Legacy tools may do this, and they historically have accepted everything.
+ // Preserve that behavior by ignoring //go:build constraints entirely in that case.
+ if (v.before(check.version) && check.version.before(go1_21)) || check.version.equal(go0_0) {
+ continue
+ }
+ if check.posVers == nil {
+ check.posVers = make(map[token.Pos]version)
+ }
+ check.posVers[file.FileStart] = v
+ check.recordFileVersion(file, file.GoVersion) // overwrite package version
+ }
+ }
}
// A bailout panic is used for early termination.
var errBadCgo = errors.New("cannot use FakeImportC and go115UsesCgo together")
func (check *Checker) checkFiles(files []*ast.File) (err error) {
+ if check.pkg == Unsafe {
+ // Defensive handling for Unsafe, which cannot be type checked, and must
+ // not be mutated. See https://go.dev/issue/61212 for an example of where
+ // Unsafe is passed to NewChecker.
+ return nil
+ }
+
+ // Note: parseGoVersion and the subsequent checks should happen once,
+ // when we create a new Checker, not for each batch of files.
+ // We can't change it at this point because NewChecker doesn't
+ // return an error.
+ check.version, err = parseGoVersion(check.conf.GoVersion)
+ if err != nil {
+ return err
+ }
+ if check.version.after(version{1, goversion.Version}) {
+ return fmt.Errorf("package requires newer Go version %v", check.version)
+ }
if check.conf.FakeImportC && check.conf.go115UsesCgo {
return errBadCgo
}
defer check.handleBailout(&err)
print := func(msg string) {
- if check.conf.trace {
+ if check.conf._Trace {
fmt.Println()
fmt.Println(msg)
}
check.monomorph()
}
+ check.pkg.goVersion = check.conf.GoVersion
check.pkg.complete = true
// no longer needed - release memory
// this is a sufficiently bounded process.
for i := top; i < len(check.delayed); i++ {
a := &check.delayed[i]
- if check.conf.trace {
+ if check.conf._Trace {
if a.desc != nil {
check.trace(a.desc.pos.Pos(), "-- "+a.desc.format, a.desc.args...)
} else {
- check.trace(token.NoPos, "-- delayed %p", a.f)
+ check.trace(nopos, "-- delayed %p", a.f)
}
}
a.f() // may append to check.delayed
- if check.conf.trace {
+ if check.conf._Trace {
fmt.Println()
}
}
assert(val != nil)
// We check allBasic(typ, IsConstType) here as constant expressions may be
// recorded as type parameters.
- assert(typ == Typ[Invalid] || allBasic(typ, IsConstType))
+ assert(!isValid(typ) || allBasic(typ, IsConstType))
}
if m := check.Types; m != nil {
m[x] = TypeAndValue{mode, typ, val}
}
}
-func (check *Checker) recordCommaOkTypes(x ast.Expr, a [2]Type) {
+// recordCommaOkTypes updates recorded types to reflect that x is used in a commaOk context
+// (and therefore has tuple type).
+func (check *Checker) recordCommaOkTypes(x ast.Expr, a []*operand) {
assert(x != nil)
- if a[0] == nil || a[1] == nil {
+ assert(len(a) == 2)
+ if a[0].mode == invalid {
return
}
- assert(isTyped(a[0]) && isTyped(a[1]) && (isBoolean(a[1]) || a[1] == universeError))
+ t0, t1 := a[0].typ, a[1].typ
+ assert(isTyped(t0) && isTyped(t1) && (isBoolean(t1) || t1 == universeError))
if m := check.Types; m != nil {
for {
tv := m[x]
assert(tv.Type != nil) // should have been recorded already
pos := x.Pos()
tv.Type = NewTuple(
- NewVar(pos, check.pkg, "", a[0]),
- NewVar(pos, check.pkg, "", a[1]),
+ NewVar(pos, check.pkg, "", t0),
+ NewVar(pos, check.pkg, "", t1),
)
m[x] = tv
// if x is a parenthesized expression (p.X), update p.X
m[node] = scope
}
}
+
+func (check *Checker) recordFileVersion(file *ast.File, version string) {
+ if m := check.FileVersions; m != nil {
+ m[file] = version
+ }
+}