Fix #13478 FP unreachableCode within switch (danmar#7137)

Author: chrchr-github

lib/checkother.cpp

@@ -903,7 +903,14 @@ void CheckOther::checkUnreachableCode()
             }
             while (Token::simpleMatch(secondBreak, "}") && secondBreak->scope()->type == Scope::ScopeType::eUnconditional)
                 secondBreak = secondBreak->next();
-            if (Token::simpleMatch(secondBreak, ";"))
+            if (secondBreak && secondBreak->scope()->nestedIn && secondBreak->scope()->nestedIn->type == Scope::ScopeType::eSwitch &&
+                tok->str() == "break") {
+                while (Token::simpleMatch(secondBreak, "{") && secondBreak->scope()->type == Scope::ScopeType::eUnconditional)
+                    secondBreak = secondBreak->next();
+                if (Token::Match(secondBreak, "%name% :"))
+                    continue;
+            }
+            if (Token::simpleMatch(secondBreak, "; }"))
                 continue;
 
             // Statements follow directly, no line between them. (#3383)

test/testother.cpp

@@ -5649,6 +5649,16 @@ class TestOther : public TestFixture {
               "    { return 0; };\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("int f(int i) {\n" // #13478
+              "    int x = 0;\n"
+              "    switch (i) {\n"
+              "        { case 0: x = 5; break; }\n"
+              "        { case 1: x = 7; break; }\n"
+              "    }\n"
+              "    return x;\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
     }