add support for custom functional interfaces

src/main/java/org/jsweet/transpiler/typescript/Java2TypeScriptTranslator.java

@@ -769,7 +769,9 @@ public class Java2TypeScriptTranslator extends AbstractTreePrinter {
 				report(methodDecl, methodDecl.name, JSweetProblem.WRONG_USE_OF_AMBIENT, methodDecl.name);
 			}
 		}
+		if(!Util.hasAnnotationType(parent.sym, FunctionalInterface.class.getName())) {
 			printIdentifier(getTSMethodName(methodDecl));
+		}
 		if (methodDecl.typarams != null && !methodDecl.typarams.isEmpty()) {
 			print("<").printArgList(methodDecl.typarams).print(">");
 		}
@@ -1161,6 +1163,9 @@ public class Java2TypeScriptTranslator extends AbstractTreePrinter {
 			} else {
 				if (inv.meth instanceof JCFieldAccess) {
 					JCExpression selected = ((JCFieldAccess) inv.meth).selected;
+					if(Util.hasAnnotationType(selected.type.tsym, FunctionalInterface.class.getName())) {
+						anonymous = true;
+					}
 					methSym = Util.findMethodDeclarationInType(context.types, selected.type.tsym, methName, type);
 					if (methSym != null) {
 						typeChecker.checkApply(inv, methSym);

src/test/java/org/jsweet/test/transpiler/TypingTests.java

@@ -26,6 +26,7 @@ import org.junit.Test;
 import source.typing.ArraysOfLambdas;
 import source.typing.ClassTypeAsFunction;
 import source.typing.ClassTypeAsTypeOf;
+import source.typing.CustomLambdas;
 import source.typing.CustomStringTypes;
 import source.typing.InvalidIndexedAccesses;
 import source.typing.Lambdas;
@@ -192,4 +193,13 @@ public class TypingTests extends AbstractTest {
 		}
 	}
 
+	@Test
+	public void testCustomLambdas() {
+		eval((logHandler, r) -> {
+			logHandler.assertReportedProblems();
+			Assert.assertEquals("test1", r.get("lambda"));
+		} , getSourceFile(CustomLambdas.class));
+	}
+
+	
 }

src/test/java/source/typing/CustomLambdas.java

@@ -0,0 +1,38 @@
+/* 
+ * JSweet - http://www.jsweet.org
+ * Copyright (C) 2015 CINCHEO SAS <renaud.pawlak@cincheo.fr>
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package source.typing;
+
+import static jsweet.util.Globals.$export;
+
+@FunctionalInterface
+interface MyFunction {
+	void run(int i, String s);
+}
+
+public class CustomLambdas {
+
+	void m(MyFunction f) {
+		f.run(1, "test");
+	}
+
+	public static void main(String[] args) {
+		new CustomLambdas().m((i, s) -> {
+			$export("lambda", s + i);
+		});
+	}
+
+}