Completion: multiple extension methods with different substitutions may be shown

idea/ide-common/src/org/jetbrains/jet/plugin/codeInsight/ReferenceVariantsHelper.kt

@@ -133,7 +133,7 @@ public class ReferenceVariantsHelper(
 
             for (descriptor in resolutionScope.getDescriptorsFiltered(kindFilter, nameFilter)) {
                 if (descriptor is CallableDescriptor && descriptor.getExtensionReceiverParameter() != null) {
-                    descriptorsSet.addIfNotNull(descriptor.substituteExtensionIfCallable(receiverValues, context, dataFlowInfo, false))
+                    descriptorsSet.addAll(descriptor.substituteExtensionIfCallable(receiverValues, context, dataFlowInfo, false))
                 }
                 else {
                     descriptorsSet.add(descriptor)
@@ -201,8 +201,7 @@ public class ReferenceVariantsHelper(
     ) {
         if (!kindFilter.excludes.contains(DescriptorKindExclude.Extensions)) {
             for (callable in resolutionScope.getDescriptorsFiltered(kindFilter.exclude(DescriptorKindExclude.NonExtensions), nameFilter)) {
-                val substituted = (callable as CallableDescriptor).substituteExtensionIfCallable(receiver, isInfixCall, context, dataFlowInfo)
-                addIfNotNull(substituted)
+                addAll((callable as CallableDescriptor).substituteExtensionIfCallable(receiver, isInfixCall, context, dataFlowInfo))
             }
         }
     }

idea/ide-common/src/org/jetbrains/jet/plugin/util/extensionsUtils.kt

@@ -35,18 +35,14 @@ import java.util.HashSet
 import org.jetbrains.jet.lang.descriptors.ReceiverParameterDescriptor
 import org.jetbrains.jet.lang.types.TypeSubstitutor
 
-//TODO: what if multiple receiver types match? this can result in different substitutions
-
 public fun CallableDescriptor.substituteExtensionIfCallable(receivers: Collection<ReceiverValue>,
                                                   context: BindingContext,
                                                   dataFlowInfo: DataFlowInfo,
-                                                  isInfixCall: Boolean): CallableDescriptor? {
-    return receivers.stream()
-            .map { substituteExtensionIfCallable(it, isInfixCall, context, dataFlowInfo) }
-            .firstOrNull { it != null }
+                                                  isInfixCall: Boolean): Collection<CallableDescriptor> {
+    return receivers.flatMap { substituteExtensionIfCallable(it, isInfixCall, context, dataFlowInfo) }
 }
 
-public fun CallableDescriptor.substituteExtensionIfCallableWithImplicitReceiver(scope: JetScope, context: BindingContext, dataFlowInfo: DataFlowInfo): CallableDescriptor?
+public fun CallableDescriptor.substituteExtensionIfCallableWithImplicitReceiver(scope: JetScope, context: BindingContext, dataFlowInfo: DataFlowInfo): Collection<CallableDescriptor>
         = substituteExtensionIfCallable(scope.getImplicitReceiversHierarchy().map { it.getValue() }, context, dataFlowInfo, false)
 
 public fun CallableDescriptor.substituteExtensionIfCallable(
@@ -54,21 +50,18 @@ public fun CallableDescriptor.substituteExtensionIfCallable(
         isInfixCall: Boolean,
         bindingContext: BindingContext,
         dataFlowInfo: DataFlowInfo
-): CallableDescriptor? {
+): Collection<CallableDescriptor> {
     val receiverParameter = getExtensionReceiverParameter()!!
-    if (!receiver.exists()) return null
+    if (!receiver.exists()) return listOf()
 
     if (isInfixCall && (this !is SimpleFunctionDescriptor || getValueParameters().size() != 1)) {
-        return null
+        return listOf()
     }
 
-    for (type in SmartCastUtils.getSmartCastVariants(receiver, bindingContext, dataFlowInfo)) {
-        val substitutor = checkReceiverResolution(type, receiverParameter, getTypeParameters())
-        if (substitutor != null) {
-            return substitute(substitutor)
-        }
-    }
-    return null
+    return SmartCastUtils.getSmartCastVariants(receiver, bindingContext, dataFlowInfo)
+            .map { checkReceiverResolution(it, receiverParameter, getTypeParameters()) }
+            .filterNotNull()
+            .map { substitute(it) }
 }
 
 private fun checkReceiverResolution(

idea/src/org/jetbrains/jet/plugin/caches/KotlinIndicesHelper.kt

@@ -162,8 +162,7 @@ public class KotlinIndicesHelper(
 
         return descriptors.stream()
                 .filter(visibilityFilter)
-                .map { it.substituteExtensionIfCallable(receiverValue, isInfixCall, bindingContext, dataFlowInfo) }
-                .filterNotNull()
+                .flatMap { it.substituteExtensionIfCallable(receiverValue, isInfixCall, bindingContext, dataFlowInfo).stream() }
     }
 
     public fun getClassDescriptors(nameFilter: (String) -> Boolean, kindFilter: (ClassKind) -> Boolean): Collection<ClassDescriptor> {

idea/src/org/jetbrains/jet/plugin/completion/DeclarationDescriptorLookupObject.kt

@@ -20,6 +20,7 @@ import com.intellij.openapi.diagnostic.Logger
 import com.intellij.psi.PsiElement
 import org.jetbrains.jet.lang.descriptors.DeclarationDescriptor
 import org.jetbrains.jet.plugin.caches.resolve.ResolutionFacade
+import org.jetbrains.jet.lang.descriptors.CallableDescriptor
 
 /**
  * Stores information about resolved descriptor and position of that descriptor.
@@ -49,8 +50,20 @@ public class DeclarationDescriptorLookupObject(
             return false
         }
 
-        //TODO: different substitutions
-        return lookupObject.descriptor.getOriginal() == descriptor.getOriginal()
+        if (lookupObject.descriptor.getOriginal() != descriptor.getOriginal()) return false
+        if (descriptor !is CallableDescriptor) return true
+        return substitutionsEqual(descriptor as CallableDescriptor, lookupObject.descriptor as CallableDescriptor)
+    }
+
+    private fun substitutionsEqual(callable1: CallableDescriptor, callable2: CallableDescriptor): Boolean {
+        if (callable1.getReturnType() != callable2.getReturnType()) return false
+        val parameters1 = callable1.getValueParameters()
+        val parameters2 = callable2.getValueParameters()
+        if (parameters1.size() != parameters2.size()) return false
+        for (i in parameters1.indices) {
+            if (parameters1[i].getType() != parameters2[i].getType()) return false
+        }
+        return true
     }
 
     class object {

idea/src/org/jetbrains/jet/plugin/liveTemplates/macro/BaseJetVariableMacro.java

@@ -84,7 +84,7 @@ public abstract class BaseJetVariableMacro extends Macro {
 
                 if (variableDescriptor.getExtensionReceiverParameter() != null
                     && ExtensionsUtilsPackage.substituteExtensionIfCallableWithImplicitReceiver(
-                        variableDescriptor, scope, bindingContext, dataFlowInfo) == null) {
+                        variableDescriptor, scope, bindingContext, dataFlowInfo).isEmpty()) {
                     continue;
                 }
 

idea/testData/completion/basic/common/SubstitutedSignature4.kt

@@ -0,0 +1,14 @@
+trait Trait<T>
+
+fun<T> Trait<T>.extension(t: T): T = t
+
+class Outer : Trait<String> {
+    inner class Inner : Trait<Int> {
+        fun foo() {
+            ext<caret>
+        }
+    }
+}
+
+// EXIST: { itemText: "extension", tailText: "(t: String) for Trait<String> in <root>", typeText: "String" }
+// EXIST: { itemText: "extension", tailText: "(t: Int) for Trait<Int> in <root>", typeText: "Int" }

idea/tests/org/jetbrains/jet/completion/JSBasicCompletionTestGenerated.java

@@ -820,6 +820,12 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
             doTest(fileName);
         }
 
+        @TestMetadata("SubstitutedSignature4.kt")
+        public void testSubstitutedSignature4() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/SubstitutedSignature4.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("TopLevelClassCompletionInQualifiedCall.kt")
         public void testTopLevelClassCompletionInQualifiedCall() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/TopLevelClassCompletionInQualifiedCall.kt");

idea/tests/org/jetbrains/jet/completion/JvmBasicCompletionTestGenerated.java

@@ -820,6 +820,12 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
             doTest(fileName);
         }
 
+        @TestMetadata("SubstitutedSignature4.kt")
+        public void testSubstitutedSignature4() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/SubstitutedSignature4.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("TopLevelClassCompletionInQualifiedCall.kt")
         public void testTopLevelClassCompletionInQualifiedCall() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/completion/basic/common/TopLevelClassCompletionInQualifiedCall.kt");

idea/tests/org/jetbrains/jet/completion/weighers/BasicCompletionWeigherTestGenerated.java

@@ -19,6 +19,7 @@ package org.jetbrains.jet.completion.weighers;
 import com.intellij.testFramework.TestDataPath;
 import org.jetbrains.jet.JUnit3RunnerWithInners;
 import org.jetbrains.jet.JetTestUtils;
+import org.jetbrains.jet.test.InnerTestClasses;
 import org.jetbrains.jet.test.TestMetadata;
 import org.junit.runner.RunWith;