Handle conditional escape

Author: Your Name

lib/forwardanalyzer.cpp

@@ -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.

test/testcondition.cpp

@@ -4935,6 +4935,37 @@ class TestCondition : public TestFixture {
               "    if (v > 0) {}\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("bool f();\n" // a modification after a conditional escape must still be seen
+              "int main() {\n"
+              "    bool datumAdded = false;\n"
+              "    if (f()) {\n"
+              "        if (f()) return 1;\n"
+              "        if (f()) datumAdded = true;\n"
+              "    }\n"
+              "    if (datumAdded) {}\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+
+        check("bool f();\n"
+              "int main() {\n"
+              "    bool b = false;\n"
+              "    if (f()) {\n"
+              "        if (f()) return 1;\n"
+              "        b = true;\n"
+              "    }\n"
+              "    if (b) {}\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+
+        check("bool f();\n" // the branch always escapes - keep the known value
+              "int main() {\n"
+              "    bool b = false;\n"
+              "    if (f()) { b = true; return 1; }\n"
+              "    if (b) {}\n"
+              "}\n");
+        ASSERT_EQUALS("[test.cpp:5:9]: (style) Condition 'b' is always false [knownConditionTrueFalse]\n",
+                      errout_str());
     }
 
     void alwaysTrueSymbolic()