Kapt: provide a default constructor if PsiClass does not have any

(cherry picked from commit 550b1c0)

plugins/java-model-wrappers/src/org/jetbrains/kotlin/java/model/elements/JeTypeElement.kt

@@ -21,6 +21,7 @@ import com.intellij.psi.impl.source.PsiClassReferenceType
 import com.intellij.psi.util.ClassUtil
 import com.intellij.psi.util.PsiTypesUtil
 import org.jetbrains.kotlin.java.model.*
+import org.jetbrains.kotlin.java.model.internal.DefaultConstructorPsiMethod
 import org.jetbrains.kotlin.java.model.types.JeNoneType
 import org.jetbrains.kotlin.java.model.types.toJeType
 import javax.lang.model.element.*
@@ -75,9 +76,35 @@ class JeTypeElement(override val psi: PsiClass) : JeElement, TypeElement, JeAnno
         psi.fields.forEach { declarations += JeVariableElement(it) }
         psi.methods.forEach { declarations += JeMethodExecutableElement(it) }
         psi.innerClasses.forEach { declarations += JeTypeElement(it) }
+        
+        // Add default constructor if possible
+        if (!psi.isInterface && !psi.isAnnotationType && psi.constructors.isEmpty()) {
+            val superClass = psi.superClass
+            val canHaveDefaultConstructor = superClass == null || run {
+                val constructors = superClass.constructors
+                constructors.isEmpty() || constructors.any {
+                    (it.hasModifierProperty(PsiModifier.PUBLIC) || it.hasModifierProperty(PsiModifier.PROTECTED) || run {
+                        it.hasModifierProperty(PsiModifier.PACKAGE_LOCAL) && psi.packageName == superClass.packageName
+                    }) && it.parameterList.parametersCount == 0 
+                }
+            }
+            
+            if (canHaveDefaultConstructor) {
+                declarations += JeMethodExecutableElement(DefaultConstructorPsiMethod(psi, psi.language).apply {
+                    val containingClass = psi.containingClass
+                    if (containingClass != null && !psi.hasModifierProperty(PsiModifier.STATIC)) {
+                        addParameter("\$instance", PsiTypesUtil.getClassType(containingClass))
+                    }
+                })
+            }
+        }
+        
         return declarations
     }
     
+    private val PsiClass.packageName: String
+        get() = (containingFile as? PsiJavaFile)?.packageName ?: ""
+    
     fun getAllMembers(): List<Element> {
         val declarations = mutableListOf<Element>()
         psi.allFields.forEach { declarations += JeVariableElement(it) }

plugins/java-model-wrappers/src/org/jetbrains/kotlin/java/model/internal/DefaultConstructorPsiMethod.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2016 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 org.jetbrains.kotlin.java.model.internal
+
+import com.intellij.lang.Language
+import com.intellij.psi.PsiClass
+import com.intellij.psi.PsiModifier.*
+import com.intellij.psi.impl.light.LightMethodBuilder
+
+internal class DefaultConstructorPsiMethod(
+        clazz: PsiClass,
+        language: Language
+) : LightMethodBuilder(clazz, language) {
+    init {
+        val modifier = when {
+            clazz.hasModifierProperty(PUBLIC) -> PUBLIC
+            clazz.hasModifierProperty(PRIVATE) -> PRIVATE
+            clazz.hasModifierProperty(PROTECTED) -> PROTECTED
+            else -> PACKAGE_LOCAL
+        }
+        setModifiers(modifier)
+        isConstructor = true
+    }
+}