const src1 = `
package p
var _ T
`
	_, err := typecheck(src1, &conf, nil)
	if err == nil || !strings.HasSuffix(err.Error(), " [go.dev/e/UndeclaredName]") {
		t.Errorf("src1: unexpected error: got %v", err)
	}

	// test case for a multi-line error
	const src2 = `
package p
func f() int { return 0 }
var _ = f(1, 2)
`
	_, err = typecheck(src2, &conf, nil)

	const src1 = `
package p
var _ T
`
	_, err := typecheck(src1, &conf, nil)
	if err == nil || !strings.HasSuffix(err.Error(), " [go.dev/e/UndeclaredName]") {
		t.Errorf("src1: unexpected error: got %v", err)
	}

	// test case for a multi-line error
	const src2 = `
package p
func f() int { return 0 }
var _ = f(1, 2)
`
	_, err = typecheck(src2, &conf, nil)

var (
	typepkgmu sync.Mutex // protects typepkg lookups
	typepkg   = NewPkg("type", "type")
)

var SimType [NTYPE]Kind

// Fake package for shape types (see typecheck.Shapify()).

// This list remains here just as a reference and for comparison - these files all pass.
var _ = setOf(
	"import1.go",      // types2 reports extra errors
	"initializerr.go", // types2 reports extra error
	"typecheck.go",    // types2 reports extra error at function call

	"fixedbugs/bug176.go", // types2 reports all errors (pref: types2)
	"fixedbugs/bug195.go", // types2 reports slight different errors, and an extra error

func newTarget(typ Type, desc string) *target {
	if typ != nil {
		if sig, _ := under(typ).(*Signature); sig != nil {
			return &target{sig, desc}
		}
	}
	return nil
}

// rawExpr typechecks expression e and initializes x with the expression
// value or type. If an error occurred, x.mode is set to invalid.
// If a non-nil target T is given and e is a generic function,
// T is used to infer the type arguments for e.

func newTarget(typ Type, desc string) *target {
	if typ != nil {
		if sig, _ := under(typ).(*Signature); sig != nil {
			return &target{sig, desc}
		}
	}
	return nil
}

// rawExpr typechecks expression e and initializes x with the expression
// value or type. If an error occurred, x.mode is set to invalid.
// If a non-nil target T is given and e is a generic function,
// T is used to infer the type arguments for e.