Properly determine what classes to show in Kotlin completion:

Classes like Int and jet.Iterable should are not visible from Java
since they are erased at runtime. We call such classes non-physical,
they have to be added to completion manually.`

compiler/frontend/src/org/jetbrains/jet/lang/types/lang/KotlinBuiltIns.java

@@ -135,6 +135,8 @@ public class KotlinBuiltIns {
     private final ResolveSession resolveSession;
     private final ModuleDescriptor builtInsModule;
 
+    private ImmutableSet<ClassDescriptor> nonPhysicalClasses;
+
     private final ImmutableList<ClassDescriptor> functionClasses;
     private final ImmutableSet<ClassDescriptor> functionClassesSet;
 
@@ -183,6 +185,8 @@ public class KotlinBuiltIns {
     }
 
     private void initialize() {
+        nonPhysicalClasses = computeNonPhysicalClasses();
+
         for (PrimitiveType primitive : PrimitiveType.values()) {
             makePrimitive(primitive);
         }
@@ -541,6 +545,63 @@ public class KotlinBuiltIns {
         return getBuiltInClassByName("MutableListIterator");
     }
 
+    /**
+     * Classes that only exist for the Kotlin compiler: they are erased at runtime.
+     * As a consequence they, for example, shouldn't be referred to by other languages
+     * (e.g. Java).
+     */
+    @NotNull
+    public Set<ClassDescriptor> getNonPhysicalClasses() {
+        return nonPhysicalClasses;
+    }
+
+    @NotNull
+    private ImmutableSet<ClassDescriptor> computeNonPhysicalClasses() {
+        ImmutableSet.Builder<ClassDescriptor> nonPhysical = ImmutableSet.builder();
+        nonPhysical.add(
+                getAny(),
+                getNothing(),
+
+                getNumber(),
+                getString(),
+                getCharSequence(),
+                getThrowable(),
+                getBuiltInClassByName("Hashable"),
+
+                getIterator(),
+                getIterable(),
+                getCollection(),
+                getList(),
+                getListIterator(),
+                getSet(),
+                getMap(),
+                getMapEntry(),
+
+                getMutableIterator(),
+                getMutableIterable(),
+                getMutableCollection(),
+                getMutableList(),
+                getMutableListIterator(),
+                getMutableSet(),
+                getMutableMap(),
+                getMutableMapEntry(),
+
+                getVolatileAnnotationClass(),
+                getDataClassAnnotation(),
+                getAnnotation(),
+                getComparable(),
+                getEnum(),
+                getArray()
+        );
+
+        for (PrimitiveType primitiveType : values()) {
+            nonPhysical.add(getPrimitiveClassDescriptor(primitiveType));
+            nonPhysical.add(getPrimitiveArrayClassDescriptor(primitiveType));
+        }
+
+        return nonPhysical.build();
+    }
+
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
     // GET TYPE

idea/src/org/jetbrains/jet/plugin/caches/JetShortNamesCache.java

@@ -16,8 +16,6 @@
 
 package org.jetbrains.jet.plugin.caches;
 
-import com.google.common.base.Function;
-import com.google.common.collect.Collections2;
 import com.google.common.collect.Sets;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Condition;
@@ -29,7 +27,6 @@ import com.intellij.util.Processor;
 import com.intellij.util.containers.HashSet;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.asJava.JavaElementFinder;
 import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.psi.*;
@@ -44,7 +41,6 @@ import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.resolve.scopes.JetScope;
 import org.jetbrains.jet.lang.types.JetType;
 import org.jetbrains.jet.lang.types.expressions.ExpressionTypingUtils;
-import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
 import org.jetbrains.jet.plugin.stubindex.JetExtensionFunctionNameIndex;
 import org.jetbrains.jet.plugin.stubindex.JetFullClassNameIndex;
 import org.jetbrains.jet.plugin.stubindex.JetShortClassNameIndex;
@@ -113,25 +109,6 @@ public class JetShortNamesCache extends PsiShortNamesCache {
         destination.addAll(Arrays.asList(getAllClassNames()));
     }
 
-    /**
-     * Types that should be visible in completion from kotlin but should be absent in java.
-     * @return
-     */
-    @NotNull
-    public static Collection<DeclarationDescriptor> getJetOnlyTypes() {
-        Collection<DeclarationDescriptor> standardTypes =
-                Collections2.transform(KotlinBuiltIns.getInstance().getAllBuiltInClasses(),
-                                       new Function<DeclarationDescriptor, DeclarationDescriptor>() {
-                                           @Override
-                                           public DeclarationDescriptor apply(@Nullable DeclarationDescriptor classDescriptor) {
-                                               assert classDescriptor != null;
-                                               return classDescriptor;
-                                           }
-                                       });
-
-        return standardTypes;
-    }
-
     /**
      * Get jet non-extension top-level function names. Method is allowed to give invalid names - all result should be
      * checked with getTopLevelFunctionDescriptorsByName().

idea/src/org/jetbrains/jet/plugin/completion/JetClassCompletionContributor.java

@@ -32,6 +32,7 @@ import org.jetbrains.jet.lang.psi.JetFile;
 import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.resolve.lazy.ResolveSession;
 import org.jetbrains.jet.lang.resolve.lazy.ResolveSessionUtils;
+import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
 import org.jetbrains.jet.plugin.caches.JetCacheManager;
 import org.jetbrains.jet.plugin.caches.JetShortNamesCache;
 import org.jetbrains.jet.plugin.completion.handlers.JetJavaClassInsertHandler;
@@ -58,7 +59,7 @@ public class JetClassCompletionContributor extends CompletionContributor {
     ) {
         CompletionResultSet tempResult = result.withPrefixMatcher(CompletionUtil.findReferenceOrAlphanumericPrefix(parameters));
 
-        final Collection<DeclarationDescriptor> jetOnlyClasses = JetShortNamesCache.getJetOnlyTypes();
+        final Collection<ClassDescriptor> jetOnlyClasses = KotlinBuiltIns.getInstance().getNonPhysicalClasses();
         for (DeclarationDescriptor jetOnlyClass : jetOnlyClasses) {
             consumer.consume(DescriptorLookupConverter.createLookupElement(resolveSession, jetContext, jetOnlyClass));
         }

idea/testData/completion/class/InExpressionNoPrefix.kt

@@ -4,5 +4,6 @@ class Test {
     }
 }
 
+// RUNTIME: 1
 // EXIST: Any, Nothing, Tuple0, Int, Number
 // EXIST: Array, Math, Hashable, OutputStream

idea/testData/completion/class/InExtendTypeAnnotation.kt

@@ -3,5 +3,6 @@ class Test : <caret> {
     }
 }
 
+// RUNTIME: 1
 // EXIST: Any, Nothing, Tuple0, Int, Number
 // EXIST: Array, Math, Hashable, OutputStream