Utils: Fix small string

Change-Id: I6a746eb28c6c803b9ade9f626a950cf93ba6fe99
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/libs/utils/smallstring.h

@@ -615,7 +615,13 @@ public:
 
     friend BasicSmallString operator+(SmallStringView first, const BasicSmallString &second)
     {
-        return operator+(second, first);
+        BasicSmallString text;
+        text.reserve(first.size() + second.size());
+
+        text.append(first);
+        text.append(second);
+
+        return text;
     }
 
     template<size_type ArraySize>

tests/unit/unittest/smallstring-test.cpp

@@ -1657,6 +1657,15 @@ TEST(SmallString, StringViewPlusOperator)
     ASSERT_THAT(result, "text and more text");
 }
 
+TEST(SmallString, StringViewPlusOperatorReverseOrder)
+{
+    SmallStringView text = " and more text";
+
+    auto result = "text" + text;
+
+    ASSERT_THAT(result, "text and more text");
+}
+
 TEST(SmallString, StringPlusOperator)
 {
     SmallString text = "text";
@@ -1666,6 +1675,15 @@ TEST(SmallString, StringPlusOperator)
     ASSERT_THAT(result, "text and more text");
 }
 
+TEST(SmallString, StringPlusOperatorReverseOrder)
+{
+    SmallString text = " and more text";
+
+    auto result = "text" + text;
+
+    ASSERT_THAT(result, "text and more text");
+}
+
 TEST(SmallString, ShortStringCapacity)
 {
     ASSERT_THAT(SmallString().shortStringCapacity(), 30);