Kapt: Support default constant values for constructor parameters

plugins/kapt3/kapt3-compiler/src/org/jetbrains/kotlin/kapt3/stubs/ClassFileToSourceStubConverter.kt

@@ -651,24 +651,28 @@ class ClassFileToSourceStubConverter(val kaptContext: KaptContextForStubGenerati
         val value = field.value
 
         val origin = kaptContext.origins[field]
-        val propertyInitializer = (origin?.element as? KtProperty)?.initializer
+        val initializer = when (val element = origin?.element) {
+            is KtProperty -> element.initializer
+            is KtParameter -> element.defaultValue
+            else -> null
+        }
 
         if (value != null) {
-            if (propertyInitializer != null) {
-                return convertConstantValueArguments(value, listOf(propertyInitializer))
+            if (initializer != null) {
+                return convertConstantValueArguments(value, listOf(initializer))
             }
 
             return convertValueOfPrimitiveTypeOrString(value)
         }
 
         val propertyType = (origin?.descriptor as? PropertyDescriptor)?.returnType
-        if (propertyInitializer != null && propertyType != null) {
+        if (initializer != null && propertyType != null) {
             val moduleDescriptor = kaptContext.generationState.module
             val evaluator = ConstantExpressionEvaluator(moduleDescriptor, LanguageVersionSettingsImpl.DEFAULT, kaptContext.project)
             val trace = DelegatingBindingTrace(kaptContext.bindingContext, "Kapt")
-            val const = evaluator.evaluateExpression(propertyInitializer, trace, propertyType)
+            val const = evaluator.evaluateExpression(initializer, trace, propertyType)
             if (const != null && !const.isError && const.canBeUsedInAnnotations && !const.usesNonConstValAsConstant) {
-                return convertConstantValueArguments(const.getValue(propertyType), listOf(propertyInitializer))
+                return convertConstantValueArguments(const.getValue(propertyType), listOf(initializer))
             }
         }
 

plugins/kapt3/kapt3-compiler/testData/converter/jvmOverloads.txt

@@ -5,7 +5,7 @@ public final class State {
     private final int someInt = 0;
     private final long someLong = 0L;
     @org.jetbrains.annotations.NotNull()
-    private final java.lang.String someString = null;
+    private final java.lang.String someString = "";
 
     public final int getSomeInt() {
         return 0;
@@ -38,9 +38,9 @@ import java.lang.System;
 @kotlin.Metadata()
 public final class State2 {
     public final int someInt = 0;
-    public final long someLong = 0L;
+    public final long someLong = 2L;
     @org.jetbrains.annotations.NotNull()
-    public final java.lang.String someString = null;
+    public final java.lang.String someString = "";
 
     public final int test(int someInt, long someLong, @org.jetbrains.annotations.NotNull()
     java.lang.String someString) {

plugins/kapt3/kapt3-compiler/testData/converter/kt18791.kt

@@ -66,7 +66,8 @@ annotation class Anno(
         val a8: Double,
         val a9: String)
 
-class MyActivity {
+// TODO generate the right default field value for 'p0'
+class MyActivity(val p0: Int = lib.R.id.textView, val p1: Int = 5) {
     @Bind(LibR.id.textView)
     @BindField(LibR.id.textView)
     val a = 0

plugins/kapt3/kapt3-compiler/testData/converter/kt18791.txt

@@ -134,6 +134,8 @@ public final class MyActivity {
     public final int propD = app.B.id.textView;
     public int propE = app.B.id.textView;
     private final int propF = 0;
+    private final int p0 = 0;
+    private final int p1 = 5;
 
     @Bind(id = lib.R.id.textView)
     public static void a$annotations() {
@@ -224,6 +226,18 @@ public final class MyActivity {
         return 0;
     }
 
+    public final int getP0() {
+        return 0;
+    }
+
+    public final int getP1() {
+        return 0;
+    }
+
+    public MyActivity(int p0, int p1) {
+        super();
+    }
+
     public MyActivity() {
         super();
     }

plugins/kapt3/kapt3-compiler/testData/converter/unsafePropertyInitializers.kt

@@ -21,4 +21,6 @@ object Foo {
 object Boo {
     val z = foo()
     fun foo() = "abc"
-}
+}
+
+class Zoo(val p: Int = 100)

plugins/kapt3/kapt3-compiler/testData/converter/unsafePropertyInitializers.txt

@@ -116,3 +116,25 @@ public final class Foo {
         super();
     }
 }
+
+////////////////////
+
+
+import java.lang.System;
+
+@kotlin.Metadata()
+public final class Zoo {
+    private final int p = 100;
+
+    public final int getP() {
+        return 0;
+    }
+
+    public Zoo(int p) {
+        super();
+    }
+
+    public Zoo() {
+        super();
+    }
+}

plugins/kapt3/kapt3-compiler/testData/kotlinRunner/Overloads.it.txt

@@ -26,7 +26,7 @@ public final class State {
     private final int someInt = 0;
     private final long someLong = 0L;
     @org.jetbrains.annotations.NotNull()
-    private final java.lang.String someString = null;
+    private final java.lang.String someString = "";
 
     public final int getSomeInt() {
         return 0;