Fix #12363 FP unreadVariable with unknown constructor that takes a parameter (#6305)

Author: chrchr-github

lib/checkunusedvar.cpp

@@ -1214,7 +1214,9 @@ void CheckUnusedVar::checkFunctionVariableUsage()
             const bool isPointer = tok->valueType() && (tok->valueType()->pointer || tok->valueType()->type == ValueType::SMART_POINTER);
 
             if (tok->isName()) {
-                if (isRaiiClass(tok->valueType(), tok->isCpp(), false))
+                if (isRaiiClass(tok->valueType(), tok->isCpp(), false) ||
+                    (tok->valueType() && tok->valueType()->type == ValueType::RECORD &&
+                     (!tok->valueType()->typeScope || !isRecordTypeWithoutSideEffects(tok->valueType()->typeScope->definedType))))
                     continue;
                 tok = tok->next();
             }

test/testunusedvar.cpp

@@ -142,6 +142,7 @@ class TestUnusedVar : public TestFixture {
         TEST_CASE(localvar68);
         TEST_CASE(localvar69);
         TEST_CASE(localvar70);
+        TEST_CASE(localvar71);
         TEST_CASE(localvarloops); // loops
         TEST_CASE(localvaralias1);
         TEST_CASE(localvaralias2); // ticket #1637
@@ -3906,6 +3907,12 @@ class TestUnusedVar : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void localvar71() {
+        functionVariableUsage("struct A { explicit A(int i); };\n" // #12363
+                              "void f() { A a(0); }\n");
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void localvarloops() {
         // loops
         functionVariableUsage("void fun(int c) {\n"