// Package types declares the data types and implements
// the algorithms for type-checking of Go packages. Use
-// Config.Check to invoke the type checker for a package.
-// Alternatively, create a new type checker with NewChecker
-// and invoke it incrementally by calling Checker.Files.
+// [Config.Check] to invoke the type checker for a package.
+// Alternatively, create a new type checker with [NewChecker]
+// and invoke it incrementally by calling [Checker.Files].
//
// Type-checking consists of several interdependent phases:
//
// Name resolution maps each identifier (ast.Ident) in the program to the
-// language object (Object) it denotes.
-// Use Info.{Defs,Uses,Implicits} for the results of name resolution.
+// language object ([Object]) it denotes.
+// Use [Info].{Defs,Uses,Implicits} for the results of name resolution.
//
// Constant folding computes the exact constant value (constant.Value)
// for every expression (ast.Expr) that is a compile-time constant.
// Use Info.Types[expr].Value for the results of constant folding.
//
-// Type inference computes the type (Type) of every expression (ast.Expr)
+// [Type] inference computes the type ([Type]) of every expression ([ast.Expr])
// and checks for compliance with the language specification.
-// Use Info.Types[expr].Type for the results of type inference.
+// Use [Info.Types][expr].Type for the results of type inference.
//
// For a tutorial, see https://golang.org/s/types-tutorial.
package types
"go/ast"
"go/constant"
"go/token"
+ . "internal/types/errors"
)
// An Error describes a type-checking error; it implements the error interface.
// to preview this feature may read go116code using reflection (see
// errorcodes_test.go), but beware that there is no guarantee of future
// compatibility.
- go116code errorCode
+ go116code Code
go116start token.Pos
go116end token.Pos
}
//
// CAUTION: This interface does not support the import of locally
// vendored packages. See https://golang.org/s/go15vendor.
-// If possible, external implementations should implement ImporterFrom.
+// If possible, external implementations should implement [ImporterFrom].
type Importer interface {
// Import returns the imported package for the given import path.
// The semantics is like for ImporterFrom.ImportFrom except that
// type checker will initialize this field with a newly created context.
Context *Context
- // GoVersion describes the accepted Go language version. The string
- // must follow the format "go%d.%d" (e.g. "go1.12") or it must be
- // empty; an empty string indicates the latest language version.
- // If the format is invalid, invoking the type checker will cause a
- // panic.
+ // GoVersion describes the accepted Go language version. The string must
+ // start with a prefix of the form "go%d.%d" (e.g. "go1.20", "go1.21rc1", or
+ // "go1.21.0") or it must be empty; an empty string disables Go language
+ // version checks. If the format is invalid, invoking the type checker will
+ // result in an error.
GoVersion string
// If IgnoreFuncBodies is set, function bodies are not
// It is an error to set both FakeImportC and go115UsesCgo.
go115UsesCgo bool
+ // If _Trace is set, a debug trace is printed to stdout.
+ _Trace bool
+
// If Error != nil, it is called with each error found
// during type checking; err has dynamic type Error.
// Secondary errors (for instance, to enumerate all types
// If DisableUnusedImportCheck is set, packages are not checked
// for unused imports.
DisableUnusedImportCheck bool
+
+ // If a non-empty _ErrorURL format string is provided, it is used
+ // to format an error URL link that is appended to the first line
+ // of an error message. ErrorURL must be a format string containing
+ // exactly one "%s" format, e.g. "[go.dev/e/%s]".
+ _ErrorURL string
}
func srcimporter_setUsesCgo(conf *Config) {
// in source order. Variables without an initialization expression do not
// appear in this list.
InitOrder []*Initializer
+
+ // FileVersions maps a file to its Go version string.
+ // If the file doesn't specify a version, the reported
+ // string is Config.GoVersion.
+ // Version strings begin with “go”, like “go1.21”, and
+ // are suitable for use with the [go/version] package.
+ FileVersions map[*ast.File]string
+}
+
+func (info *Info) recordTypes() bool {
+ return info.Types != nil
}
// TypeOf returns the type of expression e, or nil if not found.
// ObjectOf returns the object denoted by the specified id,
// or nil if not found.
//
-// If id is an embedded struct field, ObjectOf returns the field (*Var)
-// it defines, not the type (*TypeName) it uses.
+// If id is an embedded struct field, [Info.ObjectOf] returns the field (*[Var])
+// it defines, not the type (*[TypeName]) it uses.
//
// Precondition: the Uses and Defs maps are populated.
func (info *Info) ObjectOf(id *ast.Ident) Object {
}
// Instance reports the type arguments and instantiated type for type and
-// function instantiations. For type instantiations, Type will be of dynamic
-// type *Named. For function instantiations, Type will be of dynamic type
+// function instantiations. For type instantiations, [Type] will be of dynamic
+// type *[Named]. For function instantiations, [Type] will be of dynamic type
// *Signature.
type Instance struct {
TypeArgs *TypeList
// Check type-checks a package and returns the resulting package object and
// the first error if any. Additionally, if info != nil, Check populates each
-// of the non-nil maps in the Info struct.
+// of the non-nil maps in the [Info] struct.
//
// The package is marked as complete if no errors occurred, otherwise it is
-// incomplete. See Config.Error for controlling behavior in the presence of
+// incomplete. See [Config.Error] for controlling behavior in the presence of
// errors.
//
// The package is specified by a list of *ast.Files and corresponding
// AssertableTo reports whether a value of type V can be asserted to have type T.
//
-// The behavior of AssertableTo is undefined in two cases:
+// The behavior of AssertableTo is unspecified in three cases:
+// - if T is Typ[Invalid]
// - if V is a generalized interface; i.e., an interface that may only be used
// as a type constraint in Go code
// - if T is an uninstantiated generic type
func AssertableTo(V *Interface, T Type) bool {
// Checker.newAssertableTo suppresses errors for invalid types, so we need special
// handling here.
- if T.Underlying() == Typ[Invalid] {
+ if !isValid(T.Underlying()) {
return false
}
- return (*Checker)(nil).newAssertableTo(V, T) == nil
+ return (*Checker)(nil).newAssertableTo(nopos, V, T, nil)
}
// AssignableTo reports whether a value of type V is assignable to a variable
// of type T.
//
-// The behavior of AssignableTo is undefined if V or T is an uninstantiated
-// generic type.
+// The behavior of AssignableTo is unspecified if V or T is Typ[Invalid] or an
+// uninstantiated generic type.
func AssignableTo(V, T Type) bool {
x := operand{mode: value, typ: V}
ok, _ := x.assignableTo(nil, T, nil) // check not needed for non-constant x
// ConvertibleTo reports whether a value of type V is convertible to a value of
// type T.
//
-// The behavior of ConvertibleTo is undefined if V or T is an uninstantiated
-// generic type.
+// The behavior of ConvertibleTo is unspecified if V or T is Typ[Invalid] or an
+// uninstantiated generic type.
func ConvertibleTo(V, T Type) bool {
x := operand{mode: value, typ: V}
return x.convertibleTo(nil, T, nil) // check not needed for non-constant x
// Implements reports whether type V implements interface T.
//
-// The behavior of Implements is undefined if V is an uninstantiated generic
-// type.
+// The behavior of Implements is unspecified if V is Typ[Invalid] or an uninstantiated
+// generic type.
func Implements(V Type, T *Interface) bool {
if T.Empty() {
// All types (even Typ[Invalid]) implement the empty interface.
}
// Checker.implements suppresses errors for invalid types, so we need special
// handling here.
- if V.Underlying() == Typ[Invalid] {
+ if !isValid(V.Underlying()) {
return false
}
- return (*Checker)(nil).implements(V, T) == nil
+ return (*Checker)(nil).implements(0, V, T, false, nil)
+}
+
+// Satisfies reports whether type V satisfies the constraint T.
+//
+// The behavior of Satisfies is unspecified if V is Typ[Invalid] or an uninstantiated
+// generic type.
+func Satisfies(V Type, T *Interface) bool {
+ return (*Checker)(nil).implements(0, V, T, true, nil)
}
// Identical reports whether x and y are identical types.
-// Receivers of Signature types are ignored.
+// Receivers of [Signature] types are ignored.
func Identical(x, y Type) bool {
- return identical(x, y, true, nil)
+ var c comparer
+ return c.identical(x, y, nil)
}
// IdenticalIgnoreTags reports whether x and y are identical types if tags are ignored.
-// Receivers of Signature types are ignored.
+// Receivers of [Signature] types are ignored.
func IdenticalIgnoreTags(x, y Type) bool {
- return identical(x, y, false, nil)
+ var c comparer
+ c.ignoreTags = true
+ return c.identical(x, y, nil)
}