verify(Task)
                }
            }
        """
        then:
        succeeds "verify"
        output.contains '''configured components.main.sources
before ss1
created ss1
configured ss1
after ss1
'''
    }

                }
            }
        """
        then:
        succeeds "verify"
        output.contains '''configured components.mylib.binaries.main.sources
before ss1
created ss1
configured ss1
after ss1
'''
    }

    def "reasonable error message when adding source set with unknown type"() {
        when:
        buildFile << """

	}
	// It doesn't matter how much Preds does s0 or s1 have.
	var ss0, ss1 *Block
	s0 := b.Succs[0].b
	i0 := b.Succs[0].i
	if s0.Kind != BlockPlain || !isEmpty(s0) {
		s0, ss0 = b, s0
	} else {
		ss0 = s0.Succs[0].b
		i0 = s0.Succs[0].i
	}
	s1 := b.Succs[1].b
	i1 := b.Succs[1].i
	if s1.Kind != BlockPlain || !isEmpty(s1) {
		s1, ss1 = b, s1
	} else {
		ss1 = s1.Succs[0].b
		i1 = s1.Succs[0].i
	}
	if ss0 != ss1 {