fix #11496: FP shiftTooManyBits in dead code block (#7074)

Author: ludviggunne

lib/checktype.cpp

@@ -72,6 +72,8 @@ void CheckType::checkTooBigBitwiseShift()
         if (tok->isCpp() && Token::Match(tok, "[;{}] %name% (") && Token::simpleMatch(tok->linkAt(2), ") ;") && tok->next()->isUpperCaseName() && !tok->next()->function())
             tok = tok->linkAt(2);
 
+        tok = skipUnreachableBranch(tok);
+
         if (!tok->astOperand1() || !tok->astOperand2())
             continue;
 

test/testtype.cpp

@@ -44,6 +44,7 @@ class TestType : public TestFixture {
         TEST_CASE(longCastReturn);
         TEST_CASE(checkFloatToIntegerOverflow);
         TEST_CASE(integerOverflow); // #11794
+        TEST_CASE(shiftTooManyBits); // #11496
     }
 
 #define check(...) check_(__FILE__, __LINE__, __VA_ARGS__)
@@ -588,6 +589,18 @@ class TestType : public TestFixture {
                "}", s, "test.cpp");
         ASSERT_EQUALS("[test.cpp:4]: (error) Signed integer overflow for expression 'i<<2'.\n", errout_str());
     }
+
+    void shiftTooManyBits() { // #11496
+        check("template<unsigned int width> struct B {\n"
+              "    unsigned long long f(unsigned int n) const {\n"
+              "        if (width == 1)\n"
+              "            return 1ULL << width;\n"
+              "        return 0;\n"
+              "    }\n"
+              "};\n"
+              "static B<64> b;\n", settingsDefault);
+        ASSERT_EQUALS("", errout_str());
+    }
 };
 
 REGISTER_TEST(TestType)