// 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
import (
"go/ast"
"go/constant"
"go/token"
+ . "internal/types/errors"
)
-const allowTypeLists = false
-
// An Error describes a type-checking error; it implements the error interface.
// A "soft" error is an error that still permits a valid interpretation of a
// package (such as "unused variable"); "hard" errors may lead to unpredictable
// 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
}
return fmt.Sprintf("%s: %s", err.Fset.Position(err.Pos), err.Msg)
}
+// An ArgumentError holds an error associated with an argument index.
+type ArgumentError struct {
+ Index int
+ Err error
+}
+
+func (e *ArgumentError) Error() string { return e.Err.Error() }
+func (e *ArgumentError) Unwrap() error { return e.Err }
+
// An Importer resolves import paths to Packages.
//
// 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
// A Config specifies the configuration for type checking.
// The zero value for Config is a ready-to-use default configuration.
type Config struct {
- // 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 string
+ // Context is the context used for resolving global identifiers. If nil, the
+ // type checker will initialize this field with a newly created context.
+ Context *Context
+
+ // 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
// type-checked.
// 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) {
conf.go115UsesCgo = true
}
-// The Info struct is found in api_notypeparams.go and api_typeparams.go.
+// Info holds result type information for a type-checked package.
+// Only the information for which a map is provided is collected.
+// If the package has type errors, the collected information may
+// be incomplete.
+type Info struct {
+ // Types maps expressions to their types, and for constant
+ // expressions, also their values. Invalid expressions are
+ // omitted.
+ //
+ // For (possibly parenthesized) identifiers denoting built-in
+ // functions, the recorded signatures are call-site specific:
+ // if the call result is not a constant, the recorded type is
+ // an argument-specific signature. Otherwise, the recorded type
+ // is invalid.
+ //
+ // The Types map does not record the type of every identifier,
+ // only those that appear where an arbitrary expression is
+ // permitted. For instance, the identifier f in a selector
+ // expression x.f is found only in the Selections map, the
+ // identifier z in a variable declaration 'var z int' is found
+ // only in the Defs map, and identifiers denoting packages in
+ // qualified identifiers are collected in the Uses map.
+ Types map[ast.Expr]TypeAndValue
+
+ // Instances maps identifiers denoting generic types or functions to their
+ // type arguments and instantiated type.
+ //
+ // For example, Instances will map the identifier for 'T' in the type
+ // instantiation T[int, string] to the type arguments [int, string] and
+ // resulting instantiated *Named type. Given a generic function
+ // func F[A any](A), Instances will map the identifier for 'F' in the call
+ // expression F(int(1)) to the inferred type arguments [int], and resulting
+ // instantiated *Signature.
+ //
+ // Invariant: Instantiating Uses[id].Type() with Instances[id].TypeArgs
+ // results in an equivalent of Instances[id].Type.
+ Instances map[*ast.Ident]Instance
+
+ // Defs maps identifiers to the objects they define (including
+ // package names, dots "." of dot-imports, and blank "_" identifiers).
+ // For identifiers that do not denote objects (e.g., the package name
+ // in package clauses, or symbolic variables t in t := x.(type) of
+ // type switch headers), the corresponding objects are nil.
+ //
+ // For an embedded field, Defs returns the field *Var it defines.
+ //
+ // Invariant: Defs[id] == nil || Defs[id].Pos() == id.Pos()
+ Defs map[*ast.Ident]Object
+
+ // Uses maps identifiers to the objects they denote.
+ //
+ // For an embedded field, Uses returns the *TypeName it denotes.
+ //
+ // Invariant: Uses[id].Pos() != id.Pos()
+ Uses map[*ast.Ident]Object
+
+ // Implicits maps nodes to their implicitly declared objects, if any.
+ // The following node and object types may appear:
+ //
+ // node declared object
+ //
+ // *ast.ImportSpec *PkgName for imports without renames
+ // *ast.CaseClause type-specific *Var for each type switch case clause (incl. default)
+ // *ast.Field anonymous parameter *Var (incl. unnamed results)
+ //
+ Implicits map[ast.Node]Object
+
+ // Selections maps selector expressions (excluding qualified identifiers)
+ // to their corresponding selections.
+ Selections map[*ast.SelectorExpr]*Selection
+
+ // Scopes maps ast.Nodes to the scopes they define. Package scopes are not
+ // associated with a specific node but with all files belonging to a package.
+ // Thus, the package scope can be found in the type-checked Package object.
+ // Scopes nest, with the Universe scope being the outermost scope, enclosing
+ // the package scope, which contains (one or more) files scopes, which enclose
+ // function scopes which in turn enclose statement and function literal scopes.
+ // Note that even though package-level functions are declared in the package
+ // scope, the function scopes are embedded in the file scope of the file
+ // containing the function declaration.
+ //
+ // The following node types may appear in Scopes:
+ //
+ // *ast.File
+ // *ast.FuncType
+ // *ast.TypeSpec
+ // *ast.BlockStmt
+ // *ast.IfStmt
+ // *ast.SwitchStmt
+ // *ast.TypeSwitchStmt
+ // *ast.CaseClause
+ // *ast.CommClause
+ // *ast.ForStmt
+ // *ast.RangeStmt
+ //
+ Scopes map[ast.Node]*Scope
+
+ // InitOrder is the list of package-level initializers in the order in which
+ // they must be executed. Initializers referring to variables related by an
+ // initialization dependency appear in topological order, the others appear
+ // 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.
// Precondition: the Types, Uses and Defs maps are populated.
-//
func (info *Info) TypeOf(e ast.Expr) Type {
if t, ok := info.Types[e]; ok {
return t.Type
// 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 {
if obj := info.Defs[id]; obj != nil {
return obj
return tv.mode == commaok || tv.mode == mapindex
}
-// _Inferred reports the _Inferred type arguments and signature
-// for a parameterized function call that uses type inference.
-type _Inferred struct {
- TArgs []Type
- Sig *Signature
+// 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
+// *Signature.
+type Instance struct {
+ TypeArgs *TypeList
+ Type Type
}
// An Initializer describes a package-level variable, or a list of variables in case
// 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 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 {
- m, _ := (*Checker)(nil).assertableTo(V, T)
- return m == nil
+ // Checker.newAssertableTo suppresses errors for invalid types, so we need special
+ // handling here.
+ if !isValid(T.Underlying()) {
+ return false
+ }
+ return (*Checker)(nil).newAssertableTo(nopos, V, T, nil)
}
-// AssignableTo reports whether a value of type V is assignable to a variable of type T.
+// AssignableTo reports whether a value of type V is assignable to a variable
+// of type T.
+//
+// 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
return ok
}
-// ConvertibleTo reports whether a value of type V is convertible to a value of type T.
+// ConvertibleTo reports whether a value of type V is convertible to a value of
+// type T.
+//
+// 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 unspecified if V is Typ[Invalid] or an uninstantiated
+// generic type.
func Implements(V Type, T *Interface) bool {
- f, _ := MissingMethod(V, T, true)
- return f == nil
+ if T.Empty() {
+ // All types (even Typ[Invalid]) implement the empty interface.
+ return true
+ }
+ // Checker.implements suppresses errors for invalid types, so we need special
+ // handling here.
+ if !isValid(V.Underlying()) {
+ return false
+ }
+ 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 (*Checker)(nil).identical(x, y)
+ 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 (*Checker)(nil).identicalIgnoreTags(x, y)
+ var c comparer
+ c.ignoreTags = true
+ return c.identical(x, y, nil)
}