Merge pull request #366 from scala-native/topic/fix-365

Fix #365

nscplugin/src/main/scala/scala/scalanative/nscplugin/NirCodeGen.scala

@@ -1199,13 +1199,25 @@ abstract class NirCodeGen
     }
 
     def genStringConcat(leftp: Tree, rightp: Tree, focus: Focus): Focus = {
+      def stringify(sym: Symbol, focus: Focus) =
+        if (sym == StringClass) {
+          focus
+        } else {
+          genMethodCall(Object_toString, statically = false, focus.value, Seq(), focus)
+        }
+
       val left = {
+        val typesym = leftp.tpe.typeSymbol
         val unboxed = genExpr(leftp, focus)
-        val boxed   = boxValue(leftp.tpe.typeSymbol, unboxed)
-        genMethodCall(
-            Object_toString, statically = false, boxed.value, Seq(), boxed)
+        val boxed   = boxValue(typesym, unboxed)
+        stringify(typesym, boxed)
+      }
+
+      val right = {
+        val typesym = rightp.tpe.typeSymbol
+        val boxed   = genExpr(rightp, left)
+        stringify(typesym, boxed)
       }
-      val right = genExpr(rightp, left)
 
       genMethodCall(String_+,
                     statically = true,

unit-tests/src/main/scala/java/lang/StringSuite.scala

@@ -0,0 +1,21 @@
+package java.lang
+
+object StringSuite extends tests.Suite {
+  test("concat primitive") {
+    assert("big 5" == "big " + 5.toByte)
+    assert("big 5" == "big " + 5.toShort)
+    assert("big 5" == "big " + 5)
+    assert("big 5" == "big " + 5L)
+    assert("5 big" == 5.toByte + " big")
+    assert("5 big" == 5.toShort + " big")
+    assert("5 big" == 5 + " big")
+    assert("5 big" == 5L + " big")
+  }
+
+  test("concat string") {
+    assert("foo" == "foo" + "")
+    assert("foo" == "" + "foo")
+    assert("foobar" == "foo" + "bar")
+    assert("foobarbaz" == "foo" + "bar" + "baz")
+  }
+}

unit-tests/src/main/scala/tests/Main.scala

@@ -5,6 +5,12 @@ import java.lang.System.exit
 object Main {
   def main(args: Array[String]): Unit = {
     // tests.Discover object is code-generated in the sbt build
-    if (!tests.Discover.suites.forall(_.run)) exit(1) else exit(0)
+    val suites = tests.Discover.suites
+    var failed = false
+    suites.foreach { suite =>
+      val result = suite.run()
+      failed = failed || result
+    }
+    exit(if (failed) 1 else 0)
   }
 }

unit-tests/src/main/scala/tests/Suite.scala

@@ -51,10 +51,13 @@ abstract class Suite {
 
   def run(): Boolean = {
     println("* " + this.getClass.getName)
-    tests.forall { test =>
-      val res = test.run()
-      println((if (res) "  [ok] " else "  [fail] ") + test.name)
-      res
+    var failed = false
+    tests.foreach { test =>
+      val result = test.run()
+      val status = if (result) "  [ok] " else "  [fail] "
+      println(status + test.name)
+      failed = failed || result
     }
+    !failed
   }
 }