diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index cae64e52d..a6ea2761a 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -3844,6 +3844,13 @@ const Token* ValueFlow::getEndOfExprScope(const Token* tok, const Scope* default
                 const Token* varEnd = getEndOfVarScope(var);
                 if (!end || (smallest ? precedes(varEnd, end) : succeeds(varEnd, end)))
                     end = varEnd;
+
+                const Token* top = var->nameToken()->astTop();
+                if (top && Token::simpleMatch(top->tokAt(-1), "if (")) { // variable declared in if (...)
+                    const Token* elseTok = top->link()->linkAt(1);
+                    if (Token::simpleMatch(elseTok, "} else {") && tok->scope()->isNestedIn(elseTok->tokAt(2)->scope()))
+                        end = tok->scope()->bodyEnd;
+                }
             }
         }
         return ChildrenToVisit::op1_and_op2;
diff --git a/test/testunusedvar.cpp b/test/testunusedvar.cpp
index 181445bd0..527fb5c19 100644
--- a/test/testunusedvar.cpp
+++ b/test/testunusedvar.cpp
@@ -5446,6 +5446,37 @@ private:
                               "        return y;\n"
                               "}");
         ASSERT_EQUALS("", errout.str());
+
+        functionVariableUsage("int f(int i) {\n" // #11788
+                              "    if (int x = i) {\n"
+                              "        return x;\n"
+                              "    }\n"
+                              "    else {\n"
+                              "        x = 12;\n"
+                              "        return x;\n"
+                              "    }\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
+
+        functionVariableUsage("void f(int i) {\n"
+                              "    if (int x = i) {\n"
+                              "        while (x < 100) {\n"
+                              "            if (x % 2 == 0) {\n"
+                              "                x += 3;\n"
+                              "            }\n"
+                              "            else if (x % 3 == 0) {\n"
+                              "                x += 5;\n"
+                              "            }\n"
+                              "            else {\n"
+                              "                x += 7;\n"
+                              "            }\n"
+                              "            x += 6;\n"
+                              "        }\n"
+                              "        return x;\n"
+                              "    }\n"
+                              "    return i;\n"
+                              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void localvarOpAssign() {