}

	case *Map:
		// Two map types are identical if they have identical key and value types.
		if y, ok := y.(*Map); ok {
			return c.identical(x.key, y.key, p) && c.identical(x.elem, y.elem, p)
		}

	case *Chan:
		// Two channel types are identical if they have identical value types
		// and the same direction.
		if y, ok := y.(*Chan); ok {
			return x.dir == y.dir && c.identical(x.elem, y.elem, p)
		}

	case *Named:

		}

	case *Map:
		// Two map types are identical if they have identical key and value types.
		if y, ok := y.(*Map); ok {
			return c.identical(x.key, y.key, p) && c.identical(x.elem, y.elem, p)
		}

	case *Chan:
		// Two channel types are identical if they have identical value types
		// and the same direction.
		if y, ok := y.(*Chan); ok {
			return x.dir == y.dir && c.identical(x.elem, y.elem, p)
		}

	case *Named:

		return nil // no core type.
	}

	U = terms[0].Type().Underlying()
	var identical int // i in [0,identical) => Identical(U, terms[i].Type().Underlying())
	for identical = 1; identical < len(terms); identical++ {
		if !types.Identical(U, terms[identical].Type().Underlying()) {
			break
		}
	}

	if identical == len(terms) {
		// https://go.dev/ref/spec#Core_types

	return (*Checker)(nil).implements(nopos, V, T, true, nil)
}

// Identical reports whether x and y are identical types.
// Receivers of [Signature] types are ignored.
//
// Predicates such as [Identical], [Implements], and
// [Satisfies] assume that both operands belong to a
// consistent collection of symbols ([Object] values).
// For example, two [Named] types can be identical only if their
// [Named.Obj] methods return the same [TypeName] symbol.

	return (*Checker)(nil).implements(nopos, V, T, true, nil)
}

// Identical reports whether x and y are identical types.
// Receivers of [Signature] types are ignored.
//
// Predicates such as [Identical], [Implements], and
// [Satisfies] assume that both operands belong to a
// consistent collection of symbols ([Object] values).
// For example, two [Named] types can be identical only if their
// [Named.Obj] methods return the same [TypeName] symbol.

		}
		return su
	}
	return nil
}

// If x and y are identical, match returns x.
// If x and y are identical channels but for their direction
// and one of them is unrestricted, match returns the channel
// with the restricted direction.
// In all other cases, match returns nil.
func match(x, y Type) Type {
	// Common case: we don't have channels.
	if Identical(x, y) {
		return x
	}

		}
		return su
	}
	return nil
}

// If x and y are identical, match returns x.
// If x and y are identical channels but for their direction
// and one of them is unrestricted, match returns the channel
// with the restricted direction.
// In all other cases, match returns nil.
func match(x, y Type) Type {
	// Common case: we don't have channels.
	if Identical(x, y) {
		return x
	}

	case *types.Union:
		return h.hashUnion(t)

	case *types.Interface:
		// Interfaces are identical if they have the same set of methods, with
		// identical names and types, and they have the same set of type
		// restrictions. See go/types.identical for more details.
		var hash uint32 = 9103

		// Hash methods.
		for i, n := 0, t.NumMethods(); i < n; i++ {

	// IntArgRegs is the number of registers dedicated
	// to passing integer argument values. Result registers are identical
	// to argument registers, so this number is used for those too.
	IntArgRegs = 0

	// FloatArgRegs is the number of registers dedicated
	// to passing floating-point argument values. Result registers are
	// identical to argument registers, so this number is used for
	// those too.
	FloatArgRegs = 0

{info}> {normal}first failure
   {info}> {normal}ultimate cause
{info}> {normal}There is 1 more failure with an identical cause.

* Try:
$STACKTRACE
$INFO_OR_DEBUG
$SCAN
$GET_HELP
"""
    }

    def "multi-cause exceptions have branches with identical root causes and additional intermediate failures summarized properly"() {
        def ultimateCause = new RuntimeException("ultimate cause")