Support loading function types

compiler/testData/compileKotlinAgainstKotlin/coroutines/builder.kt

@@ -0,0 +1,32 @@
+// FILE: A.kt
+// LANGUAGE_VERSION: 1.2
+import kotlin.coroutines.experimental.*
+
+fun builder(c: suspend () -> String): String {
+    var res = "FAIL"
+    c.startCoroutine(object : Continuation<String> {
+        override val context = EmptyCoroutineContext
+        override fun resume(value: String) {
+            res = value
+        }
+        override fun resumeWithException(exception: Throwable) {
+            throw exception
+        }
+    })
+    return res
+}
+
+// FILE: B.kt
+// LANGUAGE_VERSION: 1.3
+import kotlin.coroutines.experimental.*
+
+fun ok(continuation: Continuation<String>): Any? {
+    return "OK"
+}
+
+fun box(): String {
+    if (builder(::ok) != "OK") return "FAIL 1"
+    if (builder { cont: Continuation<String> -> "OK" } != "OK") return "FAIL 2"
+    if (builder(fun (cont: Continuation<String>): Any? = "OK") != "OK") return "FAIL 2"
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/CompileKotlinAgainstKotlinTestGenerated.java

@@ -290,6 +290,11 @@ public class CompileKotlinAgainstKotlinTestGenerated extends AbstractCompileKotl
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/compileKotlinAgainstKotlin/coroutines"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.ANY, true);
         }
 
+        @TestMetadata("builder.kt")
+        public void testBuilder() throws Exception {
+            runTest("compiler/testData/compileKotlinAgainstKotlin/coroutines/builder.kt");
+        }
+
         @TestMetadata("simple.kt")
         public void testSimple() throws Exception {
             runTest("compiler/testData/compileKotlinAgainstKotlin/coroutines/simple.kt");

core/descriptors/src/org/jetbrains/kotlin/builtins/suspendFunctionTypes.kt

@@ -89,7 +89,7 @@ fun transformRuntimeFunctionTypeToSuspendFunction(funType: KotlinType, isRelease
     if (!isContinuation(continuationArgumentType.constructor.declarationDescriptor?.fqNameSafe, isReleaseCoroutines) ||
         continuationArgumentType.arguments.size != 1
     ) {
-        return null
+        return funType as? SimpleType
     }
 
     val suspendReturnType = continuationArgumentType.arguments.single().type