broken_source:
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(code, locals_, fuel):
    match = {}
    opens = []
    for i, ins in enumerate(code):
        if ins[0] in ('block', 'loop'):
            opens.append(i)
        elif ins[0] == 'end':
            match[opens.pop()] = i
    loc = list(locals_)
    stack = []
    labels = []
    pc = 0
    steps = 0
    try:
        while pc < len(code):
            if steps == fuel:
                return {'status': 'fuel', 'stack': stack, 'locals': loc}
            steps += 1
            ins = code[pc]
            op = ins[0]
            if op in ('block', 'loop'):
                labels.append({'kind': op, 'pc': pc, 'end': match[pc], 'height': len(stack),
                               'arity': ins[1] if op == 'block' else 0})
                pc += 1
            elif op == 'end':
                labels.pop()
                pc += 1
            elif op in ('br', 'br_if'):
                if op == 'br_if' and stack.pop() == 0:
                    pc += 1
                    continue
                target = labels[len(labels) - 1 - ins[1]]
                keep = stack[len(stack) - target['arity']:] if target['arity'] else []
                del stack[target['height']:]
                stack.extend(keep)
                if target['kind'] == 'loop':
                    del labels[len(labels) - ins[1]:]
                    pc = target['end'] + 1
                else:
                    del labels[len(labels) - 1 - ins[1]:]
                    pc = target['end'] + 1
            elif op == 'const':
                stack.append(ins[1])
                pc += 1
            elif op in ('add', 'sub'):
                b = stack.pop()
                a = stack.pop()
                stack.append(a + b if op == 'add' else a - b)
                pc += 1
            elif op == 'eqz':
                stack.append(1 if stack.pop() == 0 else 0)
                pc += 1
            elif op == 'get':
                stack.append(loc[ins[1]])
                pc += 1
            elif op == 'set':
                loc[ins[1]] = stack.pop()
                pc += 1
            else:
                stack.pop()
                pc += 1
    except IndexError:
        return {'status': 'trap', 'stack': stack, 'locals': loc}
    return {'status': 'done', 'stack': stack, 'locals': loc}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 3], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 4], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    900),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 41], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [41, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 1], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 10], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [13], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 1], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    21),
   {'locals': [49, 99], 'stack': [], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    900),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 42], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [42, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 2], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 20], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [23], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 2], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    22),
   {'locals': [49, 99], 'stack': [49], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    900),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 43], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [43, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 3], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 30], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [33], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 3], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    23),
   {'locals': [49, 99], 'stack': [49, 1], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 15], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [7, 0],
    900),
   {'locals': [0, 14], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 44], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [44, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 4], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 40], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [43], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 4], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    24),
   {'locals': [49, 99], 'stack': [48], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 21], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [8, 0],
    900),
   {'locals': [0, 16], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 45], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [45, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 5], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 50], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [53], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 5], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    25),
   {'locals': [48, 99], 'stack': [], 'status': 'fuel'})]]
for label, args, expected in cases[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

source:
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(code, locals_, fuel):
    match = {}
    opens = []
    for i, ins in enumerate(code):
        if ins[0] in ('block', 'loop'):
            opens.append(i)
        elif ins[0] == 'end':
            match[opens.pop()] = i
    loc = list(locals_)
    stack = []
    labels = []
    pc = 0
    steps = 0
    try:
        while pc < len(code):
            if steps == fuel:
                return {'status': 'fuel', 'stack': stack, 'locals': loc}
            steps += 1
            ins = code[pc]
            op = ins[0]
            if op in ('block', 'loop'):
                labels.append({'kind': op, 'pc': pc, 'end': match[pc], 'height': len(stack),
                               'arity': ins[1] if op == 'block' else 0})
                pc += 1
            elif op == 'end':
                labels.pop()
                pc += 1
            elif op in ('br', 'br_if'):
                if op == 'br_if' and stack.pop() == 0:
                    pc += 1
                    continue
                target = labels[len(labels) - 1 - ins[1]]
                keep = stack[len(stack) - target['arity']:] if target['arity'] else []
                del stack[target['height']:]
                stack.extend(keep)
                if target['kind'] == 'loop':
                    del labels[len(labels) - ins[1]:]
                    pc = target['pc']
                else:
                    del labels[len(labels) - 1 - ins[1]:]
                    pc = target['end'] + 1
            elif op == 'const':
                stack.append(ins[1])
                pc += 1
            elif op in ('add', 'sub'):
                b = stack.pop()
                a = stack.pop()
                stack.append(a + b if op == 'add' else a - b)
                pc += 1
            elif op == 'eqz':
                stack.append(1 if stack.pop() == 0 else 0)
                pc += 1
            elif op == 'get':
                stack.append(loc[ins[1]])
                pc += 1
            elif op == 'set':
                loc[ins[1]] = stack.pop()
                pc += 1
            else:
                stack.pop()
                pc += 1
    except IndexError:
        return {'status': 'trap', 'stack': stack, 'locals': loc}
    return {'status': 'done', 'stack': stack, 'locals': loc}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 3], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 4], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    900),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 41], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [41, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 1], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 10], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [13], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 1], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    21),
   {'locals': [49, 99], 'stack': [], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    900),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 42], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [42, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 2], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 20], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [23], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 2], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    22),
   {'locals': [49, 99], 'stack': [49], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    900),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 43], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [43, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 3], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 30], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [33], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 3], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    23),
   {'locals': [49, 99], 'stack': [49, 1], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 15], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [7, 0],
    900),
   {'locals': [0, 14], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 44], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [44, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 4], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 40], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [43], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 4], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    24),
   {'locals': [49, 99], 'stack': [48], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 21], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [8, 0],
    900),
   {'locals': [0, 16], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 45], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [45, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 5], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 50], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [53], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 5], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    25),
   {'locals': [48, 99], 'stack': [], 'status': 'fuel'})]]
for label, args, expected in cases[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

prompt:
Loops run their body once and fall out as if the branch targeted a block.

WebAssembly-style structured control over a value stack. block k / loop / end nest; each block or loop pushes a label recording its operand height and arity (block: k result values, loop: 0). br d targets the d-th enclosing label counting outward from 0; the branch keeps the top arity values, discards operands down to the label height, then for a block pops that label and continues after its end, for a loop keeps the loop label and continues at the first instruction inside the loop. br_if pops a condition and branches when it is non-zero. Other ops: const v, add, sub, eqz, get k, set k, drop. Each instruction costs one fuel. Return status (done/fuel/trap), stack and locals.

split: open-access


broken_source:
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(code, locals_, fuel):
    match = {}
    opens = []
    for i, ins in enumerate(code):
        if ins[0] in ('block', 'loop'):
            opens.append(i)
        elif ins[0] == 'end':
            match[opens.pop()] = i
    loc = list(locals_)
    stack = []
    labels = []
    pc = 0
    steps = 0
    try:
        while pc < len(code):
            if steps == fuel:
                return {'status': 'fuel', 'stack': stack, 'locals': loc}
            steps += 1
            ins = code[pc]
            op = ins[0]
            if op in ('block', 'loop'):
                labels.append({'kind': op, 'pc': pc, 'end': match[pc], 'height': len(stack),
                               'arity': ins[1] if op == 'block' else 0})
                pc += 1
            elif op == 'end':
                labels.pop()
                pc += 1
            elif op in ('br', 'br_if'):
                if op == 'br_if' and stack.pop() == 0:
                    pc += 1
                    continue
                target = labels[len(labels) - 1 - ins[1]]
                keep = stack[len(stack) - target['arity']:] if target['arity'] else []
                del stack[target['height']:]
                stack.extend(keep)
                if target['kind'] == 'loop':
                    del labels[len(labels) - 1 - ins[1]:]
                    pc = target['pc'] + 1
                else:
                    del labels[len(labels) - 1 - ins[1]:]
                    pc = target['end'] + 1
            elif op == 'const':
                stack.append(ins[1])
                pc += 1
            elif op in ('add', 'sub'):
                b = stack.pop()
                a = stack.pop()
                stack.append(a + b if op == 'add' else a - b)
                pc += 1
            elif op == 'eqz':
                stack.append(1 if stack.pop() == 0 else 0)
                pc += 1
            elif op == 'get':
                stack.append(loc[ins[1]])
                pc += 1
            elif op == 'set':
                loc[ins[1]] = stack.pop()
                pc += 1
            else:
                stack.pop()
                pc += 1
    except IndexError:
        return {'status': 'trap', 'stack': stack, 'locals': loc}
    return {'status': 'done', 'stack': stack, 'locals': loc}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 3], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 4], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    900),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 41], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [41, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 1], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 10], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [13], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 1], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    21),
   {'locals': [49, 99], 'stack': [], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    900),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 42], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [42, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 2], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 20], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [23], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 2], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    22),
   {'locals': [49, 99], 'stack': [49], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    900),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 43], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [43, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 3], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 30], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [33], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 3], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    23),
   {'locals': [49, 99], 'stack': [49, 1], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 15], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [7, 0],
    900),
   {'locals': [0, 14], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 44], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [44, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 4], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 40], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [43], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 4], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    24),
   {'locals': [49, 99], 'stack': [48], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 21], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [8, 0],
    900),
   {'locals': [0, 16], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 45], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [45, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 5], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 50], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [53], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 5], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    25),
   {'locals': [48, 99], 'stack': [], 'status': 'fuel'})]]
for label, args, expected in cases[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

meaning: Fixture-count band, not measured model difficulty

deps: stdlib

source:
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(code, locals_, fuel):
    match = {}
    opens = []
    for i, ins in enumerate(code):
        if ins[0] in ('block', 'loop'):
            opens.append(i)
        elif ins[0] == 'end':
            match[opens.pop()] = i
    loc = list(locals_)
    stack = []
    labels = []
    pc = 0
    steps = 0
    try:
        while pc < len(code):
            if steps == fuel:
                return {'status': 'fuel', 'stack': stack, 'locals': loc}
            steps += 1
            ins = code[pc]
            op = ins[0]
            if op in ('block', 'loop'):
                labels.append({'kind': op, 'pc': pc, 'end': match[pc], 'height': len(stack),
                               'arity': ins[1] if op == 'block' else 0})
                pc += 1
            elif op == 'end':
                labels.pop()
                pc += 1
            elif op in ('br', 'br_if'):
                if op == 'br_if' and stack.pop() == 0:
                    pc += 1
                    continue
                target = labels[len(labels) - 1 - ins[1]]
                keep = stack[len(stack) - target['arity']:] if target['arity'] else []
                del stack[target['height']:]
                stack.extend(keep)
                if target['kind'] == 'loop':
                    del labels[len(labels) - ins[1] + 1:]
                    pc = target['pc'] + 1
                else:
                    del labels[len(labels) - 1 - ins[1]:]
                    pc = target['end'] + 1
            elif op == 'const':
                stack.append(ins[1])
                pc += 1
            elif op in ('add', 'sub'):
                b = stack.pop()
                a = stack.pop()
                stack.append(a + b if op == 'add' else a - b)
                pc += 1
            elif op == 'eqz':
                stack.append(1 if stack.pop() == 0 else 0)
                pc += 1
            elif op == 'get':
                stack.append(loc[ins[1]])
                pc += 1
            elif op == 'set':
                loc[ins[1]] = stack.pop()
                pc += 1
            else:
                stack.pop()
                pc += 1
    except IndexError:
        return {'status': 'trap', 'stack': stack, 'locals': loc}
    return {'status': 'done', 'stack': stack, 'locals': loc}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 3], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 4], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    900),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 41], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [41, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 1], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 10], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [13], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 1], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    21),
   {'locals': [49, 99], 'stack': [], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    900),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 42], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [42, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 2], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 20], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [23], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 2], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    22),
   {'locals': [49, 99], 'stack': [49], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    900),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 43], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [43, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 3], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 30], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [33], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 3], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    23),
   {'locals': [49, 99], 'stack': [49, 1], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 15], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [7, 0],
    900),
   {'locals': [0, 14], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 44], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [44, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 4], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 40], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [43], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 4], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    24),
   {'locals': [49, 99], 'stack': [48], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 21], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [8, 0],
    900),
   {'locals': [0, 16], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 45], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [45, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 5], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 50], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [53], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 5], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    25),
   {'locals': [48, 99], 'stack': [], 'status': 'fuel'})]]
for label, args, expected in cases[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

prompt:
After a continue-style branch the label stack is one level short, so later branches exit the wrong construct.

WebAssembly-style structured control over a value stack. block k / loop / end nest; each block or loop pushes a label recording its operand height and arity (block: k result values, loop: 0). br d targets the d-th enclosing label counting outward from 0; the branch keeps the top arity values, discards operands down to the label height, then for a block pops that label and continues after its end, for a loop keeps the loop label and continues at the first instruction inside the loop. br_if pops a condition and branches when it is non-zero. Other ops: const v, add, sub, eqz, get k, set k, drop. Each instruction costs one fuel. Return status (done/fuel/trap), stack and locals.

split: open-access


broken_source:
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(code, locals_, fuel):
    match = {}
    opens = []
    for i, ins in enumerate(code):
        if ins[0] in ('block', 'loop'):
            opens.append(i)
        elif ins[0] == 'end':
            match[opens.pop()] = i
    loc = list(locals_)
    stack = []
    labels = []
    pc = 0
    steps = 0
    try:
        while pc < len(code):
            if steps == fuel:
                return {'status': 'fuel', 'stack': stack, 'locals': loc}
            steps += 1
            ins = code[pc]
            op = ins[0]
            if op in ('block', 'loop'):
                labels.append({'kind': op, 'pc': pc, 'end': match[pc], 'height': len(stack),
                               'arity': ins[1] if op == 'block' else 0})
                pc += 1
            elif op == 'end':
                labels.pop()
                pc += 1
            elif op in ('br', 'br_if'):
                if op == 'br_if' and stack[-1] == 0:
                    pc += 1
                    continue
                target = labels[len(labels) - 1 - ins[1]]
                keep = stack[len(stack) - target['arity']:] if target['arity'] else []
                del stack[target['height']:]
                stack.extend(keep)
                if target['kind'] == 'loop':
                    del labels[len(labels) - ins[1]:]
                    pc = target['pc'] + 1
                else:
                    del labels[len(labels) - 1 - ins[1]:]
                    pc = target['end'] + 1
            elif op == 'const':
                stack.append(ins[1])
                pc += 1
            elif op in ('add', 'sub'):
                b = stack.pop()
                a = stack.pop()
                stack.append(a + b if op == 'add' else a - b)
                pc += 1
            elif op == 'eqz':
                stack.append(1 if stack.pop() == 0 else 0)
                pc += 1
            elif op == 'get':
                stack.append(loc[ins[1]])
                pc += 1
            elif op == 'set':
                loc[ins[1]] = stack.pop()
                pc += 1
            else:
                stack.pop()
                pc += 1
    except IndexError:
        return {'status': 'trap', 'stack': stack, 'locals': loc}
    return {'status': 'done', 'stack': stack, 'locals': loc}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 3], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 4], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    900),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 41], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [41, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 1], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 10], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [13], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 1], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    21),
   {'locals': [49, 99], 'stack': [], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    900),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 42], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [42, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 2], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 20], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [23], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 2], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    22),
   {'locals': [49, 99], 'stack': [49], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    900),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 43], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [43, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 3], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 30], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [33], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 3], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    23),
   {'locals': [49, 99], 'stack': [49, 1], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 15], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [7, 0],
    900),
   {'locals': [0, 14], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 44], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [44, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 4], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 40], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [43], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 4], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    24),
   {'locals': [49, 99], 'stack': [48], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 21], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [8, 0],
    900),
   {'locals': [0, 16], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 45], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [45, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 5], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 50], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [53], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 5], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    25),
   {'locals': [48, 99], 'stack': [], 'status': 'fuel'})]]
for label, args, expected in cases[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

source:
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(code, locals_, fuel):
    match = {}
    opens = []
    for i, ins in enumerate(code):
        if ins[0] in ('block', 'loop'):
            opens.append(i)
        elif ins[0] == 'end':
            match[opens.pop()] = i
    loc = list(locals_)
    stack = []
    labels = []
    pc = 0
    steps = 0
    try:
        while pc < len(code):
            if steps == fuel:
                return {'status': 'fuel', 'stack': stack, 'locals': loc}
            steps += 1
            ins = code[pc]
            op = ins[0]
            if op in ('block', 'loop'):
                labels.append({'kind': op, 'pc': pc, 'end': match[pc], 'height': len(stack),
                               'arity': ins[1] if op == 'block' else 0})
                pc += 1
            elif op == 'end':
                labels.pop()
                pc += 1
            elif op in ('br', 'br_if'):
                if op == 'br_if' and stack.pop() != 0:
                    pc += 1
                    continue
                target = labels[len(labels) - 1 - ins[1]]
                keep = stack[len(stack) - target['arity']:] if target['arity'] else []
                del stack[target['height']:]
                stack.extend(keep)
                if target['kind'] == 'loop':
                    del labels[len(labels) - ins[1]:]
                    pc = target['pc'] + 1
                else:
                    del labels[len(labels) - 1 - ins[1]:]
                    pc = target['end'] + 1
            elif op == 'const':
                stack.append(ins[1])
                pc += 1
            elif op in ('add', 'sub'):
                b = stack.pop()
                a = stack.pop()
                stack.append(a + b if op == 'add' else a - b)
                pc += 1
            elif op == 'eqz':
                stack.append(1 if stack.pop() == 0 else 0)
                pc += 1
            elif op == 'get':
                stack.append(loc[ins[1]])
                pc += 1
            elif op == 'set':
                loc[ins[1]] = stack.pop()
                pc += 1
            else:
                stack.pop()
                pc += 1
    except IndexError:
        return {'status': 'trap', 'stack': stack, 'locals': loc}
    return {'status': 'done', 'stack': stack, 'locals': loc}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 3], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [2, 0],
    500),
   {'locals': [0, 4], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    900),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 41], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [41, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 1], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 10], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [13], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 1], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    21),
   {'locals': [49, 99], 'stack': [], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [3, 0],
    500),
   {'locals': [0, 6], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    900),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 42], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [42, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 2], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 20], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [23], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 2], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    22),
   {'locals': [49, 99], 'stack': [49], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [4, 0],
    500),
   {'locals': [0, 8], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    900),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 43], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [43, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 3], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 30], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [33], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 3], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    23),
   {'locals': [49, 99], 'stack': [49, 1], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 15], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [5, 0],
    500),
   {'locals': [0, 10], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [7, 0],
    900),
   {'locals': [0, 14], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 44], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [44, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 4], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 40], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [43], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 4], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    24),
   {'locals': [49, 99], 'stack': [48], 'status': 'fuel'})],
 [('regression: counted loop exits through outer block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 21], 'stack': [], 'status': 'done'}),
  ('continue from inside a nested block',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [6, 0],
    500),
   {'locals': [0, 12], 'stack': [], 'status': 'done'}),
  ('continue loop with more iterations',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['block', 0],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['get', 1],
     ['const', 2],
     ['add'],
     ['set', 1],
     ['br', 1],
     ['end'],
     ['const', 999],
     ['set', 1],
     ['end'],
     ['end']],
    [8, 0],
    900),
   {'locals': [0, 16], 'stack': [], 'status': 'done'}),
  ('block result keeps one value above outer operand',
   ([['const', 45], ['block', 1], ['const', 5], ['const', 7], ['br', 0], ['const', 99], ['end']], [], 50),
   {'locals': [], 'stack': [45, 7], 'status': 'done'}),
  ('void block branch discards operands',
   ([['block', 0], ['const', 1], ['const', 5], ['br', 0], ['end'], ['const', 3]], [], 50),
   {'locals': [], 'stack': [3], 'status': 'done'}),
  ('untaken br_if consumes its condition',
   ([['const', 50], ['block', 0], ['const', 0], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [53], 'status': 'done'}),
  ('taken br_if exits the block',
   ([['const', 10], ['block', 0], ['const', 5], ['br_if', 0], ['const', 3], ['add'], ['end']], [], 50),
   {'locals': [], 'stack': [10], 'status': 'done'}),
  ('control: fuel exhaustion',
   ([['block', 0],
     ['loop', 0],
     ['get', 0],
     ['eqz'],
     ['br_if', 1],
     ['get', 1],
     ['get', 0],
     ['add'],
     ['set', 1],
     ['get', 0],
     ['const', 1],
     ['sub'],
     ['set', 0],
     ['br', 0],
     ['end'],
     ['end']],
    [50, 0],
    25),
   {'locals': [48, 99], 'stack': [], 'status': 'fuel'})]]
for label, args, expected in cases[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

prompt:
Code after a failed conditional branch computes with an extra zero on the stack.

WebAssembly-style structured control over a value stack. block k / loop / end nest; each block or loop pushes a label recording its operand height and arity (block: k result values, loop: 0). br d targets the d-th enclosing label counting outward from 0; the branch keeps the top arity values, discards operands down to the label height, then for a block pops that label and continues after its end, for a loop keeps the loop label and continues at the first instruction inside the loop. br_if pops a condition and branches when it is non-zero. Other ops: const v, add, sub, eqz, get k, set k, drop. Each instruction costs one fuel. Return status (done/fuel/trap), stack and locals.

split: open-access