KT-675 Translate accessible parameters as a var parameters

src/org/jetbrains/jet/j2k/Converter.java

@@ -1,6 +1,8 @@
 package org.jetbrains.jet.j2k;
 
 import com.intellij.psi.*;
+import com.intellij.psi.search.searches.ReferencesSearch;
+import com.intellij.psi.util.PsiUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.j2k.ast.*;
@@ -439,10 +441,20 @@ public class Converter {
   public static Parameter parameterToParameter(@NotNull PsiParameter parameter) {
     return new Parameter(
       new IdentifierImpl(parameter.getName()), // TODO: remove
-      typeToType(parameter.getType())
+      typeToType(parameter.getType()),
+      isReadOnly(parameter)
     );
   }
 
+  private static boolean isReadOnly(PsiParameter parameter) {
+    for (PsiReference r : (ReferencesSearch.search(parameter))) {
+        if (r instanceof PsiExpression && PsiUtil.isAccessedForWriting((PsiExpression) r)) {
+          return false;
+        }
+      }
+    return true;
+  }
+
   @NotNull
   public static Identifier identifierToIdentifier(@Nullable PsiIdentifier identifier) {
     if (identifier == null) return Identifier.EMPTY_IDENTIFIER;

src/org/jetbrains/jet/j2k/ast/Parameter.java

@@ -8,16 +8,24 @@ import org.jetbrains.annotations.NotNull;
 public class Parameter extends Expression {
   private final Identifier myIdentifier;
   private final Type myType;
+  private boolean myReadOnly;
 
   public Parameter(Identifier identifier, Type type) {
     myIdentifier = identifier;
     myType = type;
+    myReadOnly = true;
+  }
+
+  public Parameter(IdentifierImpl identifier, Type type, boolean readOnly) {
+    this(identifier, type);
+    myReadOnly = readOnly;
   }
 
   @NotNull
   @Override
   public String toKotlin() {
     String vararg = myType.getKind() == Kind.VARARG ? "vararg" + SPACE : EMPTY;
-    return vararg + myIdentifier.toKotlin() + SPACE + COLON + SPACE + myType.toKotlin();
+    String var = myReadOnly ? EMPTY : "var" + SPACE;
+    return vararg + var + myIdentifier.toKotlin() + SPACE + COLON + SPACE + myType.toKotlin();
   }
 }

testData/ast/function/file/varVararg.jav

@@ -0,0 +1,7 @@
+package demo;
+
+class Test {
+  void test(Object ... args) {
+    args = new Integer[] {1, 2, 3};
+  }
+}

testData/ast/function/file/varVararg.kt

@@ -0,0 +1,6 @@
+namespace demo
+open class Test() {
+open fun test(vararg var args : Any?) : Unit {
+args = array(1, 2, 3)
+}
+}

testData/ast/function/file/writableParameter.jav

@@ -0,0 +1,8 @@
+package demo;
+
+class Test {
+  int test(int i) {
+    i = 10;
+    return i + 20;
+  }
+}

testData/ast/function/file/writableParameter.kt

@@ -0,0 +1,7 @@
+namespace demo
+open class Test() {
+open fun test(var i : Int) : Int {
+i = 10
+return (i + 20)
+}
+}