Allow augmented assignments on dynamic receivers

compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/tasks/TaskPrioritizer.java

@@ -147,9 +147,12 @@ public class TaskPrioritizer {
     ) {
         addMembers(explicitReceiver, c, /*static=*/false, isExplicit);
 
-        addCandidatesForDynamicReceiver(explicitReceiver, implicitReceivers, c, isExplicit);
-
-        addExtensionCandidates(explicitReceiver, implicitReceivers, c, isExplicit);
+        if (TypesPackage.isDynamic(explicitReceiver.getType())) {
+            addCandidatesForDynamicReceiver(explicitReceiver, implicitReceivers, c, isExplicit);
+        }
+        else {
+            addExtensionCandidates(explicitReceiver, implicitReceivers, c, isExplicit);
+        }
     }
 
     private static <D extends CallableDescriptor, F extends D> void addExtensionCandidates(
@@ -208,8 +211,6 @@ public class TaskPrioritizer {
             @NotNull final TaskPrioritizerContext<D, F> c,
             boolean isExplicit
     ) {
-        if (!TypesPackage.isDynamic(explicitReceiver.getType())) return;
-
         TaskPrioritizerContext<D, F> onlyDynamicReceivers = c.replaceCollectors(TasksPackage.onlyDynamicReceivers(c.callableDescriptorCollectors));
         addExtensionCandidates(explicitReceiver, implicitReceivers, onlyDynamicReceivers, isExplicit);
 

compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/tasks/dynamicCalls.kt

@@ -18,7 +18,6 @@ package org.jetbrains.jet.lang.resolve.calls.tasks
 
 import org.jetbrains.jet.lang.psi.Call
 import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor
-import org.jetbrains.jet.lang.psi.JetSimpleNameExpression
 import org.jetbrains.jet.lang.descriptors.impl.SimpleFunctionDescriptorImpl
 import org.jetbrains.jet.lang.descriptors.annotations.Annotations
 import org.jetbrains.jet.lang.descriptors.CallableMemberDescriptor
@@ -43,14 +42,13 @@ import org.jetbrains.jet.lang.resolve.calls.tasks.collectors.CallableDescriptorC
 import org.jetbrains.jet.lang.resolve.scopes.JetScope
 import org.jetbrains.jet.lang.resolve.BindingTrace
 import org.jetbrains.jet.lang.resolve.calls.tasks.collectors.CallableDescriptorCollectors
-import org.jetbrains.jet.lexer.JetToken
-import org.jetbrains.jet.lang.psi.JetOperationReferenceExpression
-import org.jetbrains.jet.lang.psi.JetArrayAccessExpression
-import java.util.ArrayList
 import org.jetbrains.jet.lang.resolve.scopes.JetScopeImpl
 import org.jetbrains.jet.utils.Printer
 import org.jetbrains.jet.lang.descriptors.FunctionDescriptor
 import org.jetbrains.jet.lang.descriptors.VariableDescriptor
+import org.jetbrains.jet.lexer.JetTokens
+import org.jetbrains.jet.lang.types.expressions.OperatorConventions
+import org.jetbrains.jet.lang.psi.JetOperationReferenceExpression
 
 object DynamicCallableDescriptors {
 
@@ -62,9 +60,27 @@ object DynamicCallableDescriptors {
         }
 
         override fun getFunctions(name: Name): Collection<FunctionDescriptor> {
+            if (isAugmentedAssignmentConvention(name)) return listOf()
             return listOf(createDynamicFunction(owner, name, call))
         }
 
+        /*
+         * Detects the case when name "plusAssign" is requested for "+=" call,
+         * since both "plus" and "plusAssign" are resolvable on dynamic receivers,
+         * we have to prefer ne of them, and prefer "plusAssign" for generality:
+         * it may be called even on a val
+         */
+        private fun isAugmentedAssignmentConvention(name: Name): Boolean {
+            val callee = call.getCalleeExpression()
+            if (callee is JetOperationReferenceExpression) {
+                val token = callee.getReferencedNameElementType()
+                if (token in JetTokens.AUGMENTED_ASSIGNMENTS && OperatorConventions.ASSIGNMENT_OPERATIONS[token] != name) {
+                    return true
+                }
+            }
+            return false
+        }
+
         override fun getProperties(name: Name): Collection<VariableDescriptor> {
             return if (call.getValueArgumentList() == null && call.getValueArguments().isEmpty()) {
                 listOf(createDynamicProperty(owner, name, call))

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/ExpressionTypingVisitorForStatements.java

@@ -36,6 +36,7 @@ import org.jetbrains.jet.lang.resolve.scopes.receivers.ExpressionReceiver;
 import org.jetbrains.jet.lang.types.JetType;
 import org.jetbrains.jet.lang.types.JetTypeInfo;
 import org.jetbrains.jet.lang.types.TypeUtils;
+import org.jetbrains.jet.lang.types.checker.JetTypeChecker;
 import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
 import org.jetbrains.jet.lexer.JetTokens;
 
@@ -284,7 +285,7 @@ public class ExpressionTypingVisitorForStatements extends ExpressionTypingVisito
         else if (assignmentOperationType != null && (assignmentOperationDescriptors.isSuccess() || !binaryOperationDescriptors.isSuccess())) {
             // There's 'plusAssign()', so we do a.plusAssign(b)
             temporaryForAssignmentOperation.commit();
-            if (!KotlinBuiltIns.getInstance().isUnit(assignmentOperationType)) {
+            if (!JetTypeChecker.DEFAULT.equalTypes(KotlinBuiltIns.getInstance().getUnitType(), assignmentOperationType)) {
                 context.trace.report(ASSIGNMENT_OPERATOR_SHOULD_RETURN_UNIT.on(operationSign, assignmentOperationDescriptors.getResultingDescriptor(), operationSign));
             }
         }

compiler/testData/diagnostics/tests/dynamicTypes/conventions.kt

@@ -72,17 +72,23 @@ fun test(d: dynamic) {
     dVar<!DEBUG_INFO_DYNAMIC!>--<!>
     <!DEBUG_INFO_DYNAMIC!>--<!>dVar
 
-//    dVar += 1
-//    dVar -= 1
-//    dVar *= 1
-//    dVar /= 1
-//    dVar %= 1
+    dVar <!DEBUG_INFO_DYNAMIC!>+=<!> 1
+    dVar <!DEBUG_INFO_DYNAMIC!>-=<!> 1
+    dVar <!DEBUG_INFO_DYNAMIC!>*=<!> 1
+    dVar <!DEBUG_INFO_DYNAMIC!>/=<!> 1
+    dVar <!DEBUG_INFO_DYNAMIC!>%=<!> 1
 
-//    d[1] += 1
-//    d[1] -= 1
-//    d[1] *= 1
-//    d[1] /= 1
-//    d[1] %= 1
+    d <!DEBUG_INFO_DYNAMIC!>+=<!> 1
+    d <!DEBUG_INFO_DYNAMIC!>-=<!> 1
+    d <!DEBUG_INFO_DYNAMIC!>*=<!> 1
+    d <!DEBUG_INFO_DYNAMIC!>/=<!> 1
+    d <!DEBUG_INFO_DYNAMIC!>%=<!> 1
+
+    <!DEBUG_INFO_DYNAMIC!>d[1]<!> <!DEBUG_INFO_DYNAMIC!>+=<!> 1
+    <!DEBUG_INFO_DYNAMIC!>d[1]<!> <!DEBUG_INFO_DYNAMIC!>-=<!> 1
+    <!DEBUG_INFO_DYNAMIC!>d[1]<!> <!DEBUG_INFO_DYNAMIC!>*=<!> 1
+    <!DEBUG_INFO_DYNAMIC!>d[1]<!> <!DEBUG_INFO_DYNAMIC!>/=<!> 1
+    <!DEBUG_INFO_DYNAMIC!>d[1]<!> <!DEBUG_INFO_DYNAMIC!>%=<!> 1
 }
 
 val dyn: dynamic = null

spec-docs/dynamic-types.md

@@ -70,6 +70,8 @@ Internally, `dynamic` is represented as a flexible type `Nothing..Any?`, with th
     the code may change its semantics just because somebody added some extension in another file.
   - This means that an extension to a normal, non-dynamic type **can not** be called on a `dynamic` receiver.
     If needed, one can force a call to an extension by casting the receiver to a static type: `(d as Foo).bar()`
+- Augmented assignments on dynamic receivers (e.g. `dyn += foo`) are resolved to `plusAssign()` function, not `plus`, for generality:
+  this permits calling them on vals (e.g. those holding collection-like objects)
 
 ## Type Argument Inference