Add KParameter.type, KType, KType.isMarkedNullable

compiler/testData/codegen/boxWithStdlib/reflection/parameters/isMarkedNullable.kt

@@ -0,0 +1,18 @@
+import kotlin.reflect.*
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class A {
+    fun <T, U : Any> foo(p1: String, p2: String?, p3: T, p4: U, p5: U?) { }
+}
+
+fun Any?.ext() {}
+
+fun box(): String {
+    val ps = A::class.declaredFunctions.single().parameters.map { it.type.isMarkedNullable }
+    assertEquals(listOf(false, false, true, false, false, true), ps)
+
+    assertTrue(Any?::ext.parameters.single().type.isMarkedNullable)
+
+    return "OK"
+}

compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java

@@ -3228,6 +3228,12 @@ public class BlackBoxWithStdlibCodegenTestGenerated extends AbstractBlackBoxCode
                 doTestWithStdlib(fileName);
             }
 
+            @TestMetadata("isMarkedNullable.kt")
+            public void testIsMarkedNullable() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/reflection/parameters/isMarkedNullable.kt");
+                doTestWithStdlib(fileName);
+            }
+
             @TestMetadata("propertySetter.kt")
             public void testPropertySetter() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxWithStdlib/reflection/parameters/propertySetter.kt");

core/builtins/src/kotlin/reflect/KParameter.kt

@@ -34,4 +34,9 @@ public interface KParameter {
      * compiled without the debug information, and others.
      */
     public val name: String?
+
+    /**
+     * Type of this parameter.
+     */
+    public val type: KType
 }

core/builtins/src/kotlin/reflect/KType.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * 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 kotlin.reflect
+
+/**
+ * Represents a type. Type is usually either a class with optional type arguments,
+ * or a type parameter of some declaration, plus nullability.
+ */
+public interface KType {
+    /**
+     * `true` if this type was marked nullable in the source code.
+     *
+     * For Kotlin types, it means that `null` value is allowed to be represented by this type.
+     * In practice it means that the type was declared with a question mark at the end.
+     * For non-Kotlin types, it means the type or the symbol which was declared with this type
+     * is annotated with a runtime-retained nullability annotation such as [javax.annotation.Nullable].
+     *
+     * Note that even if [isMarkedNullable] is false, values of the type can still be `null`.
+     * This may happen if it is a type of the type parameter with a nullable upper bound:
+     *
+     * ```
+     * fun foo<T>(t: T) {
+     *     // isMarkedNullable == false for t's type, but t can be null here
+     * }
+     * ```
+     */
+    public val isMarkedNullable: Boolean
+}

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KParameterImpl.kt

@@ -19,6 +19,7 @@ package kotlin.reflect.jvm.internal
 import org.jetbrains.kotlin.descriptors.ParameterDescriptor
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
 import kotlin.reflect.KParameter
+import kotlin.reflect.KType
 
 class KParameterImpl(
         override val index: Int,
@@ -32,4 +33,7 @@ class KParameterImpl(
         val name = valueParameter.name
         return if (name.isSpecial) null else name.asString()
     }
+
+    override val type: KType
+        get() = KTypeImpl(descriptor.getType())
 }

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KTypeImpl.kt

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2010-2015 JetBrains s.r.o.
+ *
+ * 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 kotlin.reflect.jvm.internal
+
+import org.jetbrains.kotlin.types.JetType
+import kotlin.reflect.KType
+
+class KTypeImpl(val type: JetType) : KType {
+    override val isMarkedNullable: Boolean
+        get() = type.isMarkedNullable
+}