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Fix 14895: FP knownConditionTrueFalse: regression related to ' Partial fix for 9049: False negative: uninitialized variable with nested ifs (#8680)' #8701

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Fix 14895: FP knownConditionTrueFalse: regression related to ' Partial fix for 9049: False negative: uninitialized variable with nested ifs (#8680)' #8701

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fdd0dae
Handle conditional escape
Jul 6, 2026
3a7412b
Move to valueflow
Jul 6, 2026
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5 changes: 5 additions & 0 deletions lib/forwardanalyzer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -395,6 +395,11 @@ namespace {
bool structuralUnknown = false;
const bool structuralEscape = isEscapeScope(branch.endBlock, structuralUnknown);
branch.escapeUnknown = !structuralEscape || structuralUnknown;
// The traversal stopped at the escape, so the rest of the scope was not walked; a
// fall-through path could still modify the value there - include the whole scope's
// actions so isModified() sees it.
if (branch.escapeUnknown)
branch.action |= analyzeScope(branch.endBlock);
} else {
// Detect an escape the traversal did not flag (e.g. an unknown noreturn call);
// escapeUnknown reports a possible (unknown) escape.
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32 changes: 32 additions & 0 deletions test/testvalueflow.cpp
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Expand Up @@ -3214,6 +3214,38 @@ class TestValueFlow : public TestFixture {
" return x;\n"
"}\n";
ASSERT_EQUALS(true, testValueOfXKnown(code, 3U, 0));

code = "bool f();\n" // a modification after a conditional escape must still be seen
"void g() {\n"
" bool x = false;\n"
" if (f()) {\n"
" if (f()) return;\n"
" if (f()) x = true;\n"
" }\n"
" if (x) {}\n"
"}\n";
ASSERT_EQUALS(true, testValueOfX(code, 8U, 0));
ASSERT_EQUALS(false, testValueOfXKnown(code, 8U, 0));

code = "bool f();\n"
"void g() {\n"
" bool x = false;\n"
" if (f()) {\n"
" if (f()) return;\n"
" x = true;\n"
" }\n"
" if (x) {}\n"
"}\n";
ASSERT_EQUALS(true, testValueOfX(code, 8U, 0));
ASSERT_EQUALS(false, testValueOfXKnown(code, 8U, 0));

code = "bool f();\n" // the branch always escapes - keep the known value
"void g() {\n"
" bool x = false;\n"
" if (f()) { x = true; return; }\n"
" if (x) {}\n"
"}\n";
ASSERT_EQUALS(true, testValueOfXKnown(code, 5U, 0));
}

void valueFlowAfterSwap()
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