misra.py: R14.2: Verify for loop counter modification (#2409)
* misra.py: R14.2: Verify for counter modification Add additional check to detect modification of loop counter in loop body. Related issue: https://trac.cppcheck.net/ticket/9490 Add small fix that treat all assignment operators defined in N1750 6.5.16 as has side affects. This will affects rules 13.1, 13.3, 13.5 and allow to catch some false negatives. * Add tests for fixed FPs for R13.{1,5,6} * fix * use isAssignmentOp from cppcheck data * remove unused set * handle case with empty body or syntax error * add test with outer variable * Fix FP in nested loops, add tests * Fix FP on outer variables * Fixup false positives for not loop counters
This commit is contained in:
Georgy Komarov
Daniel Marjamäki
parent
f87cd9818c
commit
c46e44e39e
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@ -256,6 +256,38 @@ def getForLoopExpressions(forToken):
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lpar.astOperand2.astOperand2.astOperand2]
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def getForLoopCounterVariables(forToken):
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""" Return a set of Variable objects defined in ``for`` statement and
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satisfy requirements to loop counter term from section 8.14 of MISRA
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document.
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"""
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if not forToken or forToken.str != 'for':
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return None
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tn = forToken.next
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if not tn or tn.str != '(':
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return None
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vars_defined = set()
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vars_exit = set()
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vars_modified = set()
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cur_clause = 1
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te = tn.link
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while tn and tn != te:
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if tn.variable:
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if cur_clause == 1 and tn.variable.nameToken == tn:
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vars_defined.add(tn.variable)
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elif cur_clause == 2:
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vars_exit.add(tn.variable)
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elif cur_clause == 3:
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if tn.next and hasSideEffectsRecursive(tn.next):
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vars_modified.add(tn.variable)
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elif tn.previous and tn.previous.str in ('++', '--'):
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vars_modified.add(tn.variable)
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if tn.str == ';':
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cur_clause += 1
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tn = tn.next
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return vars_defined & vars_exit & vars_modified
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def findCounterTokens(cond):
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if not cond:
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return []
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@ -304,7 +336,7 @@ def isFloatCounterInWhileLoop(whileToken):
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def hasSideEffectsRecursive(expr):
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if not expr:
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if not expr or expr.str == ';':
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return False
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if expr.str == '=' and expr.astOperand1 and expr.astOperand1.str == '[':
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prev = expr.astOperand1.previous
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@ -316,7 +348,7 @@ def hasSideEffectsRecursive(expr):
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e = e.astOperand1
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if e and e.str == '.':
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return False
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if expr.str in ('++', '--', '='):
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if expr.isAssignmentOp or expr.str in {'++', '--'}:
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return True
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# Todo: Check function calls
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return hasSideEffectsRecursive(expr.astOperand1) or hasSideEffectsRecursive(expr.astOperand2)
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@ -1425,6 +1457,28 @@ class MisraChecker:
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elif hasSideEffectsRecursive(expressions[1]):
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self.reportError(token, 14, 2)
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# Inspect modification of loop counter in loop body
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counter_vars = getForLoopCounterVariables(token)
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outer_scope = token.scope
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body_scope = None
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tn = token.next
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while tn and tn.next != outer_scope.bodyEnd:
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if tn.scope and tn.scope.nestedIn == outer_scope:
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body_scope = tn.scope
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break
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tn = tn.next
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if not body_scope:
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continue
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tn = body_scope.bodyStart
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while tn and tn != body_scope.bodyEnd:
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if tn.variable and tn.variable in counter_vars:
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if tn.next:
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# TODO: Check modifications in function calls
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if hasSideEffectsRecursive(tn.next):
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self.reportError(tn, 14, 2)
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tn = tn.next
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def misra_14_4(self, data):
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for token in data.tokenlist:
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if token.str != '(':
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@ -351,6 +351,12 @@ void misra_12_4() {
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struct misra_13_1_t { int a; int b; };
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void misra_13_1(int *p) {
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volatile int v;
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int a1[3] = {0, (*p)++, 2}; // 13.1
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int a2[3] = {0, ((*p) += 1), 2}; // 13.1
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int a3[3] = {0, ((*p) = 19), 2}; // 13.1
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int b[2] = {v,1};
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struct misra_13_1_t c = { .a=4, .b=5 }; // no fp
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volatile int vv;
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int v = 42;
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@ -403,10 +409,15 @@ void misra_13_4() {
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void misra_13_5() {
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if (x && (y++ < 123)){} // 13.5
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if (x || ((y += 19) > 33)){} // 13.5
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if (x || ((y = 25) > 33)){} // 13.5 13.4
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if (x || ((--y) > 33)){} // 13.5
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else {}
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}
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void misra_13_6() {
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int a = sizeof(x|=42); // 13.6
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a = sizeof(--x); // 13.6 13.3
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return sizeof(x++); // 13.6
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}
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@ -428,16 +439,25 @@ void misra_14_1() {
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void misra_14_2_init_value(int32_t *var) {
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*var = 0;
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}
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void misra_14_2(bool b) {
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for (dostuff();a<10;a++) {} // 14.2
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void misra_14_2_fn1(bool b) {
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for (;i++<10;) {} // 14.2
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for (;i<10;dostuff()) {} // TODO
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int32_t g = 0;
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int g_arr[42];
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g += 2; // no-warning
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for (int32_t i2 = 0; i2 < 8; ++i2) {
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i2 += 2; // FIXME False negative for "14.2". Trac #9490
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g += 2; // no-warning
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i2 += 2; // 14.2
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i2 |= 2; // 14.2
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g += 2;
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i2 ^= 2; // 14.2
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if (i2 == 2) {
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g += g_arr[i2];
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}
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misra_14_2_init_value(&i2); // TODO: Fix false negative in function call
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}
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for (misra_14_2_init_value(&i); i < 10; ++i) {} // no-warning FIXME: False positive for 14.2 Trac #9491
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bool abort = false;
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for (i = 0; (i < 10) && !abort; ++i) { // no-warning
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if (b) {
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@ -445,7 +465,71 @@ void misra_14_2(bool b) {
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}
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}
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for (;;) {} // no-warning
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// TODO check more variants
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int x = 10;
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for (int i = x; i < 42; i++) {
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x++; // no warning
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}
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for (int i = (x - 3); i < 42; i++) {
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x ^= 3; // no warning
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}
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for (int i = 0, j = 19; i < 42; i++) { // 12.3 14.2
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i += 12; // 14.2
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j /= 3; // TODO: 14.2
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}
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for (int i = 0; i < 19; i++) {
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for (int j = 0; j < 42; j++) {
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i--; // 14.2
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for (int k = j; k > 5; k--) {
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i++; // 14.2
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for (int h = 35; h > 5; k++) // 14.2
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{}
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}
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}
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}
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}
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static void misra_14_2_fn2()
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{
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int y = 0;
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// Handle cases when i is not treated as loop counter according MISRA
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// definition.
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for (int i = 0, j = 19; y < 10, --j > 10; y++, j--) { // 14.2 12.3
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i++; // no warning
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}
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for (int i = 0, j = 19; y < 10, --j > 10; y++, j--) { // 14.2 12.3
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i++; // no warning
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}
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for (int i = 0; y < 10; y++) { // TODO: 14.2
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i++; // no warning
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}
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for (int i = 0; i < 10; y++) { // TODO: 14.2
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i++; // no warning
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}
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for (int i = 0; y < 10; i++) { // TODO: 14.2
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i++; // no warning
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}
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for (int i = 0; i < 10; (y+=i)) {
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i++; // no warning
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}
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// i is a loop counter according MISRA definition
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for (int i = 0; i < 10; i++) {
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i++; // 14.2
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if (++i > 5) { // 14.2
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break;
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}
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}
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for (int i = 0; i < 10; (i+=42)) {
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i++; // 14.2
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}
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for (int i = 0; i < 10; (i|=y)) {
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i++; // 14.2
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}
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return 0;
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}
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struct {
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