// 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].
//
// Type-checking consists of several interdependent phases:
//
// Name resolution maps each identifier ([ast.Ident]) in the program

func (check *Checker) typ(e ast.Expr) Type {
	return check.definedType(e, nil)
}

// varType type-checks the type expression e and returns its type, or Typ[Invalid].
// The type must not be an (uninstantiated) generic type and it must not be a
// constraint interface.
func (check *Checker) varType(e ast.Expr) Type {
	typ := check.definedType(e, nil)
	check.validVarType(e, typ)
	return typ
}

func (check *Checker) objDecl(obj Object, def *TypeName) {
	if check.conf.Trace && obj.Type() == nil {
		if check.indent == 0 {
			fmt.Println() // empty line between top-level objects for readability
		}
		check.trace(obj.Pos(), "-- checking %s (%s, objPath = %s)", obj, obj.color(), pathString(check.objPath))
		check.indent++
		defer func() {
			check.indent--

func (check *Checker) typ(e syntax.Expr) Type {
	return check.definedType(e, nil)
}

// varType type-checks the type expression e and returns its type, or Typ[Invalid].
// The type must not be an (uninstantiated) generic type and it must not be a
// constraint interface.
func (check *Checker) varType(e syntax.Expr) Type {
	typ := check.definedType(e, nil)
	check.validVarType(e, typ)

func (check *Checker) objDecl(obj Object, def *TypeName) {
	if check.conf._Trace && obj.Type() == nil {
		if check.indent == 0 {
			fmt.Println() // empty line between top-level objects for readability
		}
		check.trace(obj.Pos(), "-- checking %s (%s, objPath = %s)", obj, obj.color(), pathString(check.objPath))
		check.indent++
		defer func() {
			check.indent--

	if ident.Name == "main" && check.pkg.name == "main" {
		check.error(ident, InvalidMainDecl, "cannot declare main - must be func")
		return
	}

	check.declare(check.pkg.scope, ident, obj, nopos)
	check.objMap[obj] = d
	obj.setOrder(uint32(len(check.objMap)))
}

// filename returns a filename suitable for debugging output.
func (check *Checker) filename(fileNo int) string {

		for _, check := range checks {
			// no-op the check if we've specified we want to exclude the check
			if excluded.Has(check.Name()) {
				excluded.Delete(check.Name())
				fmt.Fprintf(&individualCheckOutput, "[+]%s excluded: ok\n", check.Name())
				continue
			}
			if err := check.Check(r); err != nil {
				slis.ObserveHealthcheck(context.Background(), check.Name(), name, slis.Error)

// contexts to canonicalize instances, and it would probably be possible to
// achieve such a guarantee.

// A Context is an opaque type checking context. It may be used to share
// identical type instances across type-checked packages or calls to
// Instantiate. Contexts are safe for concurrent use.
//
// The use of a shared context does not guarantee that identical instances are
// deduplicated in all cases.

	if ident.Value == "main" && check.pkg.name == "main" {
		check.error(ident, InvalidMainDecl, "cannot declare main - must be func")
		return
	}

	check.declare(check.pkg.scope, ident, obj, nopos)
	check.objMap[obj] = d
	obj.setOrder(uint32(len(check.objMap)))
}

// filename returns a filename suitable for debugging output.
func (check *Checker) filename(fileNo int) string {

func (check *Checker) expr(T *target, x *operand, e ast.Expr) {
	check.rawExpr(T, x, e, nil, false)
	check.exclude(x, 1<<novalue|1<<builtin|1<<typexpr)
	check.singleValue(x)
}

// genericExpr is like expr but the result may also be generic.
func (check *Checker) genericExpr(x *operand, e ast.Expr) {
	check.rawExpr(nil, x, e, nil, true)
	check.exclude(x, 1<<novalue|1<<builtin|1<<typexpr)
	check.singleValue(x)
}