Fix #14962: False Positive: missingReturn: return expression misdiagnosed as missing return path (#8780)

Author: ludviggunne

lib/checkfunctions.cpp

@@ -386,7 +386,12 @@ static const Token *checkMissingReturnScope(const Token *tok, const Library &lib
                 if (!isExhaustiveSwitch(tok->link()))
                     return tok->link();
             } else if (tok->scope()->type == ScopeType::eIf) {
-                const Token *condition = tok->scope()->classDef->next()->astOperand2();
+                const Token *paren = tok->link()->linkAt(-1);
+                if (!paren || !Token::simpleMatch(paren->astOperand1(), "if")) {
+                    tok = tok->link();
+                    continue;
+                }
+                const Token *condition = paren->astOperand2();
                 if (condition && condition->hasKnownIntValue() && condition->getKnownIntValue() == 1)
                     return checkMissingReturnScope(tok, library);
                 return tok;

test/testfunctions.cpp

@@ -87,6 +87,7 @@ class TestFunctions : public TestFixture {
         TEST_CASE(checkMissingReturn6); // #13180
         TEST_CASE(checkMissingReturn7); // #14370 - FN try/catch
         TEST_CASE(checkMissingReturn8);
+        TEST_CASE(checkMissingReturn9);
         TEST_CASE(checkMissingReturnStdInt); // #14482 - FN std::int32_t
 
         // std::move for locar variable
@@ -1936,6 +1937,16 @@ class TestFunctions : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void checkMissingReturn9() {
+        check("struct S { int v; };\n"
+              " S operator/(S x, S y) { return { x.v / y.v }; }\n"
+              " S f(int a, int b) {\n"
+              "    if (b) { return S{ a } / S{ b }; }\n"
+              "    else { return {}; }\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void checkMissingReturnStdInt() {// #14482 - FN
         check("std::int32_t f() {}\n");
         ASSERT_EQUALS("[test.cpp:1:19]: (error) Found an exit path from function with non-void return type that has missing return statement [missingReturn]\n", errout_str());