Added regression tests for KT-1906 Support invoke() convention is js-backend (including classes implementing Function trait)

#KT-1906 Fixed

js/js.tests/test/org/jetbrains/k2js/test/semantics/InvokeConventionTest.java

@@ -57,4 +57,8 @@ public final class InvokeConventionTest extends AbstractExpressionTest {
     public void testInfixCall() throws Exception {
         checkFooBoxIsOk();
     }
+
+    public void testInheritFromFunctionTraits() throws Exception {
+        checkFooBoxIsOk();
+    }
 }

js/js.translator/testData/expression/invoke/cases/inheritFromFunctionTraits.kt

@@ -0,0 +1,49 @@
+package foo
+
+class Bar : Function0<String> {
+    override fun invoke() = "Bar.invoke()"
+}
+
+class Baz : Function2<Int, Boolean, String> {
+    override fun invoke(i: Int, b: Boolean) = "Baz.invoke($i, $b)"
+}
+
+class ExtBar : ExtensionFunction0<String, String> {
+    override fun String.invoke() = "ExtBar.invoke($this)"
+}
+
+class ExtBaz : ExtensionFunction2<String, Int, Boolean, String> {
+    override fun String.invoke(i: Int, b: Boolean) = "ExtBaz.invoke($this, $i, $b)"
+}
+
+class Mixed :
+        Function1<Int, String>,
+        Function2<Int, Boolean, String>,
+        ExtensionFunction1<Int, Boolean, String>,
+        ExtensionFunction2<Int, Int, Boolean, String>
+{
+    override fun invoke(i: Int) = "Mixed.invoke($i)"
+    override fun invoke(i: Int, b: Boolean) = "Mixed.invoke($i, $b)"
+    override fun Int.invoke(b: Boolean) = "ext Mixed.invoke($this, $b)"
+    override fun Int.invoke(i: Int, b: Boolean) = "ext Mixed.invoke($this, $i, $b)"
+}
+
+fun box(): String {
+    val bar = Bar()
+    val baz = Baz()
+    val extBar = ExtBar()
+    val extBaz = ExtBaz()
+    val mixed = Mixed()
+
+    assertEquals("Bar.invoke()", bar())
+    assertEquals("Baz.invoke(2, false)", baz(2, false))
+    assertEquals("ExtBar.invoke(2e2)", "2e2".extBar())
+    assertEquals("ExtBaz.invoke(29, 34, true)", "29".extBaz(34, true))
+
+    assertEquals("Mixed.invoke(45)", mixed(45))
+    assertEquals("Mixed.invoke(552, true)", mixed(552, true))
+    assertEquals("ext Mixed.invoke(21, true)", 21.mixed(true))
+    assertEquals("ext Mixed.invoke(29, 304, false)", 29.mixed(304, false))
+
+    return "OK"
+}

jslib_files.xml

@@ -2,6 +2,8 @@
     <fileset id="kotlin.builtin.files" dir="${basedir}/core/builtins">
         <include name="native/kotlin/Iterator.kt"/>
         <include name="native/kotlin/Collections.kt"/>
+        <include name="src/kotlin/ExtensionFunctions.kt"/>
+        <include name="src/kotlin/Functions.kt"/>
         <include name="src/kotlin/Iterators.kt"/>
         <include name="src/kotlin/Range.kt"/>
     </fileset>