JET-72 Type inference doesn't work when iterating over ArrayList:

substitutions fixed for methods inherited from generic superclasses

idea/src/org/jetbrains/jet/lang/descriptors/TypeParameterDescriptor.java

@@ -81,7 +81,7 @@ public class TypeParameterDescriptor extends DeclarationDescriptorImpl implement
 
     @Override
     public String toString() {
-        return typeConstructor.toString();
+        return getContainingDeclaration() + "::" + typeConstructor.toString();
     }
 
     @NotNull

idea/src/org/jetbrains/jet/lang/resolve/java/JavaClassDescriptor.java

@@ -91,4 +91,9 @@ public class JavaClassDescriptor extends MutableDeclarationDescriptor implements
     public <R, D> R accept(DeclarationDescriptorVisitor<R, D> visitor, D data) {
         return visitor.visitClassDescriptor(this, data);
     }
+
+    @Override
+    public String toString() {
+        return "java class " + typeConstructor;
+    }
 }

idea/src/org/jetbrains/jet/lang/resolve/java/JavaClassMembersScope.java

@@ -110,7 +110,11 @@ public class JavaClassMembersScope implements JetScope {
     public FunctionGroup getFunctionGroup(@NotNull String name) {
         FunctionGroup functionGroup = functionGroups.get(name);
         if (functionGroup == null) {
-            functionGroup = semanticServices.getDescriptorResolver().resolveFunctionGroup(psiClass, name, staticMembers);
+            functionGroup = semanticServices.getDescriptorResolver().resolveFunctionGroup(
+                    psiClass,
+                    staticMembers ? null : (ClassDescriptor) containingDeclaration,
+                    name,
+                    staticMembers);
             functionGroups.put(name, functionGroup);
         }
         return functionGroup;

idea/src/org/jetbrains/jet/lang/resolve/java/JavaDescriptorResolver.java

@@ -26,7 +26,7 @@ public class JavaDescriptorResolver {
 
         @Override
         public <R, D> R accept(DeclarationDescriptorVisitor<R, D> visitor, D data) {
-            throw new UnsupportedOperationException(); // TODO
+            return visitor.visitDeclarationDescriptor(this, data);
         }
     };
 
@@ -73,7 +73,6 @@ public class JavaDescriptorResolver {
         classDescriptorCache.put(psiClass.getQualifiedName(), null); // TODO
 
         String name = psiClass.getName();
-        PsiModifierList modifierList = psiClass.getModifierList();
         JavaClassDescriptor classDescriptor = new JavaClassDescriptor(
                 JAVA_ROOT
         );
@@ -86,7 +85,7 @@ public class JavaDescriptorResolver {
                 // TODO
                 psiClass.hasModifierProperty(PsiModifier.FINAL),
                 name,
-                resolveTypeParameters(psiClass.getTypeParameters()),
+                resolveTypeParameters(classDescriptor, psiClass.getTypeParameters()),
                 supertypes
 
         ));
@@ -124,10 +123,10 @@ public class JavaDescriptorResolver {
         return classDescriptor;
     }
 
-    private List<TypeParameterDescriptor> resolveTypeParameters(@NotNull PsiTypeParameter[] typeParameters) {
+    private List<TypeParameterDescriptor> resolveTypeParameters(@NotNull DeclarationDescriptor containingDeclaration, @NotNull PsiTypeParameter[] typeParameters) {
         List<TypeParameterDescriptor> result = Lists.newArrayList();
         for (PsiTypeParameter typeParameter : typeParameters) {
-            TypeParameterDescriptor typeParameterDescriptor = resolveTypeParameter(typeParameter);
+            TypeParameterDescriptor typeParameterDescriptor = resolveTypeParameter(containingDeclaration, typeParameter);
             result.add(typeParameterDescriptor);
         }
         return result;
@@ -158,11 +157,11 @@ public class JavaDescriptorResolver {
     }
 
     @NotNull
-    public TypeParameterDescriptor resolveTypeParameter(@NotNull PsiTypeParameter psiTypeParameter) {
+    public TypeParameterDescriptor resolveTypeParameter(@NotNull DeclarationDescriptor containingDeclaration, @NotNull PsiTypeParameter psiTypeParameter) {
         TypeParameterDescriptor typeParameterDescriptor = typeParameterDescriptorCache.get(psiTypeParameter);
         if (typeParameterDescriptor == null) {
-            typeParameterDescriptor = createJavaTypeParameterDescriptor(JAVA_ROOT, psiTypeParameter);
+            typeParameterDescriptor = createJavaTypeParameterDescriptor(containingDeclaration, psiTypeParameter);
-//            Tis is done inside the method: typeParameterDescriptorCache.put(psiTypeParameter, typeParameterDescriptor);
+//            This is done inside the method: typeParameterDescriptorCache.put(psiTypeParameter, typeParameterDescriptor);
         }
         return typeParameterDescriptor;
     }
@@ -245,9 +244,16 @@ public class JavaDescriptorResolver {
     }
 
     @NotNull
-    public FunctionGroup resolveFunctionGroup(@NotNull PsiClass psiClass, @NotNull String methodName, boolean staticMembers) {
+    public FunctionGroup resolveFunctionGroup(@NotNull PsiClass psiClass, @Nullable ClassDescriptor classDescriptor, @NotNull String methodName, boolean staticMembers) {
         WritableFunctionGroup writableFunctionGroup = new WritableFunctionGroup(methodName);
         final Collection<HierarchicalMethodSignature> signatures = psiClass.getVisibleSignatures();
+        TypeSubstitutor typeSubstitutor;
+        if (classDescriptor != null) {
+            typeSubstitutor = TypeUtils.buildDeepSubstitutor(classDescriptor.getDefaultType());
+        }
+        else {
+            typeSubstitutor = TypeSubstitutor.EMPTY;
+        }
         for (HierarchicalMethodSignature signature: signatures) {
             PsiMethod method = signature.getMethod();
             if (method.hasModifierProperty(PsiModifier.STATIC) != staticMembers) {
@@ -258,6 +264,9 @@ public class JavaDescriptorResolver {
             }
             FunctionDescriptor functionDescriptor = methodDescriptorCache.get(method);
             if (functionDescriptor != null) {
+                if (method.getContainingClass() != psiClass) {
+                    functionDescriptor = functionDescriptor.substitute(typeSubstitutor);
+                }
                 writableFunctionGroup.addFunction(functionDescriptor);
                 continue;
             }
@@ -270,12 +279,18 @@ public class JavaDescriptorResolver {
             );
             functionDescriptorImpl.initialize(
                     null,
-                    resolveTypeParameters(method.getTypeParameters()),
+                    resolveTypeParameters(functionDescriptorImpl, method.getTypeParameters()),
                     semanticServices.getDescriptorResolver().resolveParameterDescriptors(functionDescriptorImpl, parameters),
                     semanticServices.getTypeTransformer().transformToType(method.getReturnType())
             );
             semanticServices.getTrace().recordDeclarationResolution(method, functionDescriptorImpl);
-            writableFunctionGroup.addFunction(functionDescriptorImpl);
+            FunctionDescriptor substitutedFunctionDescriptor = functionDescriptorImpl;
+            if (method.getContainingClass() != psiClass) {
+                substitutedFunctionDescriptor = functionDescriptorImpl.substitute(typeSubstitutor);
+            }
+            if (substitutedFunctionDescriptor != null) {
+                writableFunctionGroup.addFunction(substitutedFunctionDescriptor);
+            }
             methodDescriptorCache.put(method, functionDescriptorImpl);
         }
         return writableFunctionGroup;

idea/src/org/jetbrains/jet/lang/resolve/java/JavaTypeTransformer.java

@@ -70,7 +70,7 @@ public class JavaTypeTransformer {
 
                 if (psiClass instanceof PsiTypeParameter) {
                     PsiTypeParameter typeParameter = (PsiTypeParameter) psiClass;
-                    TypeParameterDescriptor typeParameterDescriptor = resolver.resolveTypeParameter(typeParameter);
+                    TypeParameterDescriptor typeParameterDescriptor = resolver.resolveTypeParameter(JavaDescriptorResolver.JAVA_ROOT, typeParameter);
                     return typeParameterDescriptor.getDefaultType();
                 }
                 else {

idea/src/org/jetbrains/jet/lang/types/TypeSubstitutor.java

@@ -5,13 +5,18 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.descriptors.TypeParameterDescriptor;
 import org.jetbrains.jet.lang.resolve.SubstitutingScope;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 
 /**
  * @author abreslav
  */
 public class TypeSubstitutor {
 
+    public static final TypeSubstitutor EMPTY = create(Collections.<TypeConstructor, TypeProjection>emptyMap());
+
     public static final class SubstitutionException extends Exception {
         public SubstitutionException(String message) {
             super(message);
@@ -176,6 +181,10 @@ public class TypeSubstitutor {
         return new TypeProjection(effectiveProjectionKindValue,  specializeType(effectiveTypeValue, effectiveContextVariance));
     }
 
+    /*package*/ void addSubstitution(@NotNull TypeConstructor typeConstructor, @NotNull TypeProjection typeProjection) {
+        substitutionContext.put(typeConstructor, typeProjection);
+    }
+
     private static Variance asymmetricOr(Variance a, Variance b) {
         return a == Variance.INVARIANT ? b : a;
     }

idea/src/org/jetbrains/jet/lang/types/TypeUtils.java

@@ -1,6 +1,7 @@
 package org.jetbrains.jet.lang.types;
 
 import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -185,15 +186,46 @@ public class TypeUtils {
         return buildSubstitutionContext(context.getConstructor().getParameters(), context.getArguments());
     }
 
+    /**
+     * Builds a context with all the supertypes' parameters substituted
+     */
+    @NotNull
+    public static TypeSubstitutor buildDeepSubstitutor(@NotNull JetType type) {
+        TypeSubstitutor typeSubstitutor = TypeSubstitutor.create(Maps.<TypeConstructor, TypeProjection>newHashMap());
+        fillInDeepSubstitutor(type, typeSubstitutor);
+        return typeSubstitutor;
+    }
+
+    private static void fillInDeepSubstitutor(JetType context, TypeSubstitutor substitutor) {
+        List<TypeParameterDescriptor> parameters = context.getConstructor().getParameters();
+        List<TypeProjection> arguments = context.getArguments();
+        for (int i = 0; i < arguments.size(); i++) {
+            TypeProjection argument = arguments.get(i);
+            TypeParameterDescriptor typeParameterDescriptor = parameters.get(i);
+
+            JetType substitute = substitutor.substitute(argument.getType(), Variance.INVARIANT);
+            assert substitute != null;
+            TypeProjection substitutedTypeProjection = new TypeProjection(argument.getProjectionKind(), substitute);
+            substitutor.addSubstitution(typeParameterDescriptor.getTypeConstructor(), substitutedTypeProjection);
+        }
+        for (JetType supertype : context.getConstructor().getSupertypes()) {
+            fillInDeepSubstitutor(supertype, substitutor);
+        }
+    }
+
     @NotNull
     public static Map<TypeConstructor, TypeProjection> buildSubstitutionContext(@NotNull List<TypeParameterDescriptor> parameters, @NotNull List<TypeProjection> contextArguments) {
         Map<TypeConstructor, TypeProjection> parameterValues = new HashMap<TypeConstructor, TypeProjection>();
+        fillInSubstitutionContext(parameters, contextArguments, parameterValues);
+        return parameterValues;
+    }
+
+    private static void fillInSubstitutionContext(List<TypeParameterDescriptor> parameters, List<TypeProjection> contextArguments, Map<TypeConstructor, TypeProjection> parameterValues) {
         for (int i = 0, parametersSize = parameters.size(); i < parametersSize; i++) {
             TypeParameterDescriptor parameter = parameters.get(i);
             TypeProjection value = contextArguments.get(i);
             parameterValues.put(parameter.getTypeConstructor(), value);
         }
-        return parameterValues;
     }
 
     @NotNull

idea/testData/checker/regression/Jet72.jet

@@ -0,0 +1,17 @@
+// JET-72 Type inference doesn't work when iterating over ArrayList
+
+import java.util.ArrayList
+
+class Item(val room: Object) {
+   val name : String
+}
+
+val items: ArrayList<Item> = new ArrayList<Item>
+
+fun test(room : Object) {
+  for(val item: Item in items) {
+    if (item.room === room) {
+      System.out?.println("You see " + item.name)
+    }
+  }
+}