}

    def "can write and then read a block multiple times"() {
        expect:
        def block = write("test")
        read(block) == "test"
        read(block) == "test"
        read(block) == "test"
    }

    def "can write multiple blocks and read in any order"() {
        expect:
        def block1 = write("test 1")
        def block2 = write("test 2")
        def block3 = write("test 3")

        ''')
        ClassDoc classDoc = classDoc('Class', content: content)
        BlockDoc block1 = blockDoc('block1', id: 'block1', description: 'block1 description', comment: 'block1 comment', type: 'org.gradle.Type')
        BlockDoc block2 = blockDoc('block2', id: 'block2', description: 'block2 description', comment: 'block2 comment', type: 'org.gradle.Type', multivalued: true)
        _ * classDoc.classProperties >> []

	fuseLate(fun.f)
	z0, ok := fun.blocks["z0"]
	if !ok || z0.Kind == BlockInvalid {
		t.Errorf("case2 z0 is eliminated, but should not")
	}
}

func BenchmarkFuse(b *testing.B) {
	for _, n := range [...]int{1, 10, 100, 1000, 10000} {
		b.Run(strconv.Itoa(n), func(b *testing.B) {
			c := testConfig(b)

			blocks := make([]bloc, 0, 2*n+3)
			blocks = append(blocks,
				Bloc("entry",

		bid := q[n].bid
		cid := q[n].cid
		q = q[:n]

		// Add block to tour.
		blocks[bid].pos = int32(len(tour))
		tour = append(tour, bid)

		// Proceed down next child edge (if any).
		if cid == 0 {
			// This is our first visit to b. Set its depth.
			blocks[bid].depth = blocks[blocks[bid].parent].depth + 1
			// Then explore its first child.
			cid = blocks[bid].firstChild
		} else {

		b.Run(strconv.Itoa(n), func(b *testing.B) {
			c := testConfig(b)
			blocks := make([]bloc, 0, n+2)
			blocks = append(blocks,
				Bloc("entry",
					Valu("mem", OpInitMem, types.TypeMem, 0, nil),
					Goto("exit")))
			blocks = append(blocks, Bloc("exit", Exit("mem")))
			for i := 0; i < n; i++ {
				blocks = append(blocks, Bloc(fmt.Sprintf("dead%d", i), Goto("exit")))
			}
			b.ResetTimer()

	for i, b := range f.Blocks {
		idToIdx[b.ID] = i
	}

	// Set of blocks we're moving, by ID.
	move := map[ID]struct{}{}

	// Map from block ID to the moving blocks that should
	// come right after it.
	after := map[ID][]*Block{}

	// Check each loop header and decide if we want to move it.
	for _, loop := range loopnest.loops {
		b := loop.header
		var p *Block // b's in-loop predecessor

	exit := f.newSparseSet(f.NumBlocks()) // exit blocks
	defer f.retSparseSet(exit)

	// Populate idToBlock and find exit blocks.
	for _, b := range f.Blocks {
		idToBlock[b.ID] = b
		if b.Kind == BlockExit {
			exit.add(b.ID)
		}
	}

	// Expand exit to include blocks post-dominated by exit blocks.
	for {
		changed := false
		for _, id := range exit.contents() {
			b := idToBlock[id]
		NextPred:

	"fmt"
	"strings"
)

// make fake flow graph.

// The blocks of the flow graph are designated with letters A
// through Z, always including A (start block) and Z (exit
// block) The specification of a flow graph is a comma-
// separated list of block successor words, for blocks ordered
// A, B, C etc, where each block except Z has one or two
// successors, and any block except A can be a target. Within

        failure.assertThatCause(containsString("only buildscript {}, pluginManagement {} and other plugins {} script blocks are allowed before plugins {} blocks, no other statements are allowed"))
        includesLinkToUserguide()
    }

    def "settings scripts can have plugin blocks"() {
        when:
        settingsFile.text = """
          plugins {
            id "noop" version "1.0"
          }

	item   *itemBuilder
	todo   func() line
}

func (b *listBuilder) build(p buildState) Block {
	blocks := p.blocks()
	pos := p.pos()

	// list can have wrong pos b/c extend dance.
	pos.EndLine = blocks[len(blocks)-1].Pos().EndLine
Loose:
	for i, c := range blocks {
		c := c.(*Item)
		if i+1 < len(blocks) {
			if blocks[i+1].Pos().StartLine-c.EndLine > 1 {
				b.loose = true
				break Loose
			}
		}