Overload resolution is factored out as an independent module CallResolver.java

idea/src/org/jetbrains/jet/JetNodeTypes.java

@@ -117,10 +117,10 @@ public interface JetNodeTypes {
     JetNodeType CALL_EXPRESSION           = new JetNodeType("CALL_EXPRESSION", JetCallExpression.class);
     JetNodeType ARRAY_ACCESS_EXPRESSION   = new JetNodeType("ARRAY_ACCESS_EXPRESSION", JetArrayAccessExpression.class);
     JetNodeType INDICES                   = new JetNodeType("INDICES", JetContainerNode.class);
-    JetNodeType DOT_QUALIFIED_EXPRESSION = new JetNodeType("DOT_QUALIFIED_EXPRESSION", JetDotQualifiedExpression.class);
+    JetNodeType DOT_QUALIFIED_EXPRESSION  = new JetNodeType("DOT_QUALIFIED_EXPRESSION", JetDotQualifiedExpression.class);
     JetNodeType HASH_QUALIFIED_EXPRESSION = new JetNodeType("HASH_QUALIFIED_EXPRESSION", JetHashQualifiedExpression.class);
     JetNodeType SAFE_ACCESS_EXPRESSION    = new JetNodeType("SAFE_ACCESS_EXPRESSION", JetSafeQualifiedExpression.class);
-    JetNodeType PREDICATE_EXPRESSION       = new JetNodeType("PREDICATE_EXPRESSION", JetPredicateExpression.class);
+    JetNodeType PREDICATE_EXPRESSION      = new JetNodeType("PREDICATE_EXPRESSION", JetPredicateExpression.class);
 
     JetNodeType OBJECT_LITERAL            = new JetNodeType("OBJECT_LITERAL", JetObjectLiteralExpression.class);
     JetNodeType ROOT_NAMESPACE            = new JetNodeType("ROOT_NAMESPACE", JetRootNamespaceExpression.class);

idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -828,7 +828,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
         else {
             IntrinsicMethod intrinsic = (IntrinsicMethod) callable;
             List<JetExpression> args = new ArrayList<JetExpression>();
-            for (JetValueArgument argument : expression.getValueArguments()) {
+            for (ValueArgument argument : expression.getValueArguments()) {
                 args.add(argument.getArgumentExpression());
             }
             return intrinsic.generate(this, v, expressionType(expression), expression, args, receiver);
@@ -876,11 +876,11 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
         return funDescriptor;
     }
 
-    public void invokeMethodWithArguments(CallableMethod callableMethod, JetCall expression) {
+    public void invokeMethodWithArguments(CallableMethod callableMethod, JetCallElement expression) {
         invokeMethodWithArguments(callableMethod, expression, StackValue.none());
     }
 
-    public void invokeMethodWithArguments(CallableMethod callableMethod, JetCall expression, StackValue receiver) {
+    public void invokeMethodWithArguments(CallableMethod callableMethod, JetCallElement expression, StackValue receiver) {
         final Type calleeType = callableMethod.getGenerateCalleeType();
         if (calleeType != null && expression instanceof JetCallExpression) {
             gen(expression.getCalleeExpression(), calleeType);
@@ -901,7 +901,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
         callableMethod.invoke(v);
     }
 
-    private void setOwnerFromCall(CallableMethod callableMethod, JetCall expression) {
+    private void setOwnerFromCall(CallableMethod callableMethod, JetCallElement expression) {
         if (expression.getParent() instanceof JetQualifiedExpression) {
             final JetExpression receiver = ((JetQualifiedExpression) expression.getParent()).getReceiverExpression();
             JetType expressionType = bindingContext.get(BindingContext.EXPRESSION_TYPE, receiver);
@@ -993,10 +993,10 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
         return false;
     }
 
-    private void pushMethodArguments(JetCall expression, List<Type> valueParameterTypes) {
+    private void pushMethodArguments(JetCallElement expression, List<Type> valueParameterTypes) {
-        List<JetValueArgument> args = expression.getValueArguments();
+        List<? extends ValueArgument> args = expression.getValueArguments();
         for (int i = 0, argsSize = args.size(); i < argsSize; i++) {
-            JetValueArgument arg = args.get(i);
+            ValueArgument arg = args.get(i);
             gen(arg.getArgumentExpression(), valueParameterTypes.get(i));
         }
     }
@@ -1430,7 +1430,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
         return StackValue.onStack(type);
     }
 
-    private void pushTypeArguments(JetCall expression) {
+    private void pushTypeArguments(JetCallElement expression) {
         for (JetTypeProjection jetTypeArgument : expression.getTypeArguments()) {
             pushTypeArgument(jetTypeArgument);
         }
@@ -1458,7 +1458,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
     }
 
     private void generateNewArray(JetCallExpression expression, Type type) {
-        List<JetValueArgument> args = expression.getValueArguments();
+        List<? extends ValueArgument> args = expression.getValueArguments();
         if (args.size() != 1) {
             throw new CompilationException("array constructor requires one value argument");
         }

idea/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java

@@ -294,7 +294,7 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
         return outerDescriptor instanceof ClassDescriptor ? (ClassDescriptor) outerDescriptor : null;
     }
 
-    private void generateDelegatorToConstructorCall(InstructionAdapter iv, ExpressionCodegen codegen, JetCall constructorCall,
+    private void generateDelegatorToConstructorCall(InstructionAdapter iv, ExpressionCodegen codegen, JetCallElement constructorCall,
                                                     ConstructorDescriptor constructorDescriptor, boolean isJavaSuperclass,
                                                     ConstructorFrameMap frameMap) {
         ClassDescriptor classDecl = constructorDescriptor.getContainingDeclaration();

idea/src/org/jetbrains/jet/lang/JetSemanticServices.java

@@ -25,13 +25,11 @@ public class JetSemanticServices {
 
     private final JetStandardLibrary standardLibrary;
     private final JetTypeChecker typeChecker;
-    private final OverloadResolver overloadResolver;
     private final JetControlFlowDataTraceFactory flowDataTraceFactory;
 
     private JetSemanticServices(JetStandardLibrary standardLibrary, JetControlFlowDataTraceFactory flowDataTraceFactory) {
         this.standardLibrary = standardLibrary;
         this.typeChecker = new JetTypeChecker(standardLibrary);
-        this.overloadResolver = new OverloadResolver(typeChecker);
         this.flowDataTraceFactory = flowDataTraceFactory;
     }
 
@@ -54,10 +52,4 @@ public class JetSemanticServices {
     public JetTypeChecker getTypeChecker() {
         return typeChecker;
     }
-
-    @NotNull
-    public OverloadResolver getOverloadResolver() {
-        return overloadResolver;
-    }
-
 }

idea/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java

@@ -530,8 +530,8 @@ public class JetControlFlowProcessor {
             builder.read(expression);
         }
 
-        private void visitCall(JetCall call) {
+        private void visitCall(JetCallElement call) {
-            for (JetValueArgument argument : call.getValueArguments()) {
+            for (ValueArgument argument : call.getValueArguments()) {
                 JetExpression argumentExpression = argument.getArgumentExpression();
                 if (argumentExpression != null) {
                     value(argumentExpression, false, false);

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

@@ -73,13 +73,10 @@ public class FunctionDescriptorUtil {
             if (substitutedType == null) return null;
             result.add(new ValueParameterDescriptorImpl(
                     substitutedDescriptor,
-                    i,
+                    unsubstitutedValueParameter,
                     unsubstitutedValueParameter.getAnnotations(),
-                    unsubstitutedValueParameter.getName(),
                     unsubstitutedValueParameter.getInType() == null ? null : substitutedType,
-                    substitutedType,
+                    substitutedType
-                    unsubstitutedValueParameter.hasDefaultValue(),
-                    unsubstitutedValueParameter.isVararg()
             ));
         }
         return result;

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

@@ -64,9 +64,17 @@ public class LazySubstitutingFunctionGroup implements FunctionGroup {
     @Override
     public Set<FunctionDescriptor> getFunctionDescriptors() {
         if (functionDescriptors == null) {
-            functionDescriptors = Sets.newHashSet();
+            if (substitutor.isEmpty()) {
-            for (FunctionDescriptor descriptor : functionGroup.getFunctionDescriptors()) {
+                functionDescriptors = functionGroup.getFunctionDescriptors();
-                functionDescriptors.add(descriptor.substitute(substitutor));
+            }
+            else {
+                functionDescriptors = Sets.newHashSet();
+                for (FunctionDescriptor descriptor : functionGroup.getFunctionDescriptors()) {
+                    FunctionDescriptor substitute = descriptor.substitute(substitutor);
+                    if (substitute != null) {
+                        functionDescriptors.add(substitute);
+                    }
+                }
             }
         }
         return functionDescriptors;

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

@@ -16,6 +16,7 @@ public class ValueParameterDescriptorImpl extends VariableDescriptorImpl impleme
     private final boolean isVararg;
     private final boolean isVar;
     private final int index;
+    private final ValueParameterDescriptor original;
 
     public ValueParameterDescriptorImpl(
             @NotNull DeclarationDescriptor containingDeclaration,
@@ -27,6 +28,7 @@ public class ValueParameterDescriptorImpl extends VariableDescriptorImpl impleme
             boolean hasDefaultValue,
             boolean isVararg) {
         super(containingDeclaration, annotations, name, inType, outType);
+        this.original = this;
         this.index = index;
         this.hasDefaultValue = hasDefaultValue;
         this.isVararg = isVararg;
@@ -35,17 +37,17 @@ public class ValueParameterDescriptorImpl extends VariableDescriptorImpl impleme
 
     public ValueParameterDescriptorImpl(
             @NotNull DeclarationDescriptor containingDeclaration,
-            int index,
+            @NotNull ValueParameterDescriptor original,
             @NotNull List<AnnotationDescriptor> annotations,
-            @NotNull String name,
+            @Nullable JetType inType,
-            boolean isVar,
+            @NotNull JetType outType
-            boolean hasDefaultValue,
+            ) {
-            boolean isVararg) {
+        super(containingDeclaration, annotations, original.getName(), inType, outType);
-        super(containingDeclaration, annotations, name, null, null);
+        this.original = original;
-        this.index = index;
+        this.index = original.getIndex();
-        this.hasDefaultValue = hasDefaultValue;
+        this.hasDefaultValue = original.hasDefaultValue();
-        this.isVararg = isVararg;
+        this.isVararg = original.isVararg();
-        this.isVar = isVar;
+        this.isVar = inType != null;
     }
 
     @Override
@@ -61,12 +63,6 @@ public class ValueParameterDescriptorImpl extends VariableDescriptorImpl impleme
     @Override
     public int getIndex() {
         return index;
-//        final JetDeclaration element = getPsiElement();
-//        final PsiElement parent = element.getParent();
-//        if (parent instanceof JetParameterList) {
-//            return ((JetParameterList) parent).getParameters().indexOf(element);
-//        }
-//        throw new IllegalStateException("couldn't find index for parameter");
     }
 
     @Override
@@ -86,7 +82,13 @@ public class ValueParameterDescriptorImpl extends VariableDescriptorImpl impleme
 
     @NotNull
     @Override
-    public VariableDescriptor substitute(TypeSubstitutor substitutor) {
+    public ValueParameterDescriptor getOriginal() {
+        return original == this ? this : original.getOriginal();
+    }
+
+    @NotNull
+    @Override
+    public ValueParameterDescriptor substitute(TypeSubstitutor substitutor) {
         throw new UnsupportedOperationException(); // TODO
     }
 

idea/src/org/jetbrains/jet/lang/psi/Call.java

@@ -1,6 +1,5 @@
 package org.jetbrains.jet.lang.psi;
 
-import com.intellij.psi.PsiElement;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -9,7 +8,7 @@ import java.util.List;
 /**
  * @author abreslav
  */
-public interface JetCall extends PsiElement {
+public interface Call {
     @Nullable
     JetExpression getCalleeExpression();
 
@@ -17,7 +16,7 @@ public interface JetCall extends PsiElement {
     JetValueArgumentList getValueArgumentList();
 
     @NotNull
-    List<JetValueArgument> getValueArguments();
+    List<? extends ValueArgument> getValueArguments();
 
     @NotNull
     List<JetExpression> getFunctionLiteralArguments();
@@ -25,6 +24,6 @@ public interface JetCall extends PsiElement {
     @NotNull
     List<JetTypeProjection> getTypeArguments();
 
-    @NotNull
+    @Nullable
-    JetElement asElement();
+    JetTypeArgumentList getTypeArgumentList();
 }

idea/src/org/jetbrains/jet/lang/psi/JetAnnotationEntry.java

@@ -11,7 +11,7 @@ import java.util.List;
 /**
  * @author max
  */
-public class JetAnnotationEntry extends JetElement implements JetCall {
+public class JetAnnotationEntry extends JetElement implements JetCallElement {
     public JetAnnotationEntry(@NotNull ASTNode node) {
         super(node);
     }
@@ -48,7 +48,7 @@ public class JetAnnotationEntry extends JetElement implements JetCall {
 
     @NotNull
     @Override
-    public List<JetValueArgument> getValueArguments() {
+    public List<? extends ValueArgument> getValueArguments() {
         JetValueArgumentList list = getValueArgumentList();
         return list != null ? list.getArguments() : Collections.<JetValueArgument>emptyList();
     }
@@ -62,20 +62,25 @@ public class JetAnnotationEntry extends JetElement implements JetCall {
     @NotNull
     @Override
     public List<JetTypeProjection> getTypeArguments() {
-        JetTypeReference typeReference = getTypeReference();
+        JetTypeArgumentList typeArgumentList = getTypeArgumentList();
-        if (typeReference != null) {
+        if (typeArgumentList == null) {
-            JetTypeElement typeElement = typeReference.getTypeElement();
+            return Collections.emptyList();
-            if (typeElement instanceof JetUserType) {
-                JetUserType userType = (JetUserType) typeElement;
-                return userType.getTypeArguments();
-            }
         }
-        return Collections.emptyList();
+        return typeArgumentList.getArguments();
     }
 
-    @NotNull
     @Override
-    public JetElement asElement() {
+    public JetTypeArgumentList getTypeArgumentList() {
-        return this;
+        JetTypeReference typeReference = getTypeReference();
+        if (typeReference == null) {
+            return null;
+        }
+        JetTypeElement typeElement = typeReference.getTypeElement();
+        if (typeElement instanceof JetUserType) {
+            JetUserType userType = (JetUserType) typeElement;
+            return userType.getTypeArgumentList();
+        }
+        return null;
     }
+
 }

idea/src/org/jetbrains/jet/lang/psi/JetBinaryExpression.java

@@ -54,5 +54,4 @@ public class JetBinaryExpression extends JetExpression {
     public IElementType getOperationToken() {
         return getOperationReference().getReferencedNameElementType();
     }
-
 }

idea/src/org/jetbrains/jet/lang/psi/JetCallElement.java

@@ -0,0 +1,14 @@
+package org.jetbrains.jet.lang.psi;
+
+import com.intellij.psi.PsiElement;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * @author abreslav
+ */
+public interface JetCallElement extends PsiElement, Call {
+
+}

idea/src/org/jetbrains/jet/lang/psi/JetCallExpression.java

@@ -11,7 +11,7 @@ import java.util.List;
 /**
  * @author max
  */
-public class JetCallExpression extends JetExpression implements JetCall {
+public class JetCallExpression extends JetExpression implements JetCallElement {
     public JetCallExpression(@NotNull ASTNode node) {
         super(node);
     }
@@ -49,15 +49,9 @@ public class JetCallExpression extends JetExpression implements JetCall {
         return findChildrenByType(JetNodeTypes.FUNCTION_LITERAL_EXPRESSION);
     }
 
-    @NotNull
-    @Override
-    public JetElement asElement() {
-        return this;
-    }
-
     @Override
     @NotNull
-    public List<JetValueArgument> getValueArguments() {
+    public List<? extends ValueArgument> getValueArguments() {
         JetValueArgumentList list = getValueArgumentList();
         return list != null ? list.getArguments() : Collections.<JetValueArgument>emptyList();
     }

idea/src/org/jetbrains/jet/lang/psi/JetDelegatorToSuperCall.java

@@ -11,7 +11,7 @@ import java.util.List;
 /**
  * @author max
  */
-public class JetDelegatorToSuperCall extends JetDelegationSpecifier implements JetCall {
+public class JetDelegatorToSuperCall extends JetDelegationSpecifier implements JetCallElement {
     public JetDelegatorToSuperCall(@NotNull ASTNode node) {
         super(node);
     }
@@ -38,7 +38,7 @@ public class JetDelegatorToSuperCall extends JetDelegationSpecifier implements J
     }
 
     @NotNull
-    public List<JetValueArgument> getValueArguments() {
+    public List<? extends ValueArgument> getValueArguments() {
         JetValueArgumentList list = getValueArgumentList();
         return list != null ? list.getArguments() : Collections.<JetValueArgument>emptyList();
     }
@@ -57,20 +57,25 @@ public class JetDelegatorToSuperCall extends JetDelegationSpecifier implements J
     @NotNull
     @Override
     public List<JetTypeProjection> getTypeArguments() {
-        JetTypeReference typeReference = getTypeReference();
+        JetTypeArgumentList typeArgumentList = getTypeArgumentList();
-        if (typeReference != null) {
+        if (typeArgumentList == null) {
-            JetTypeElement typeElement = typeReference.getTypeElement();
+            return Collections.emptyList();
-            if (typeElement instanceof JetUserType) {
-                JetUserType userType = (JetUserType) typeElement;
-                return userType.getTypeArguments();
-            }
         }
-        return Collections.emptyList();
+        return typeArgumentList.getArguments();
     }
 
-    @NotNull
     @Override
-    public JetElement asElement() {
+    public JetTypeArgumentList getTypeArgumentList() {
-        return this;
+        JetTypeReference typeReference = getTypeReference();
+        if (typeReference == null) {
+            return null;
+        }
+        JetTypeElement typeElement = typeReference.getTypeElement();
+        if (typeElement instanceof JetUserType) {
+            JetUserType userType = (JetUserType) typeElement;
+            return userType.getTypeArgumentList();
+        }
+        return null;
     }
+
 }

idea/src/org/jetbrains/jet/lang/psi/JetDelegatorToThisCall.java

@@ -11,7 +11,7 @@ import java.util.List;
 /**
  * @author max
  */
-public class JetDelegatorToThisCall extends JetDelegationSpecifier implements JetCall {
+public class JetDelegatorToThisCall extends JetDelegationSpecifier implements JetCallElement {
 
     public JetDelegatorToThisCall(@NotNull ASTNode node) {
         super(node);
@@ -38,7 +38,7 @@ public class JetDelegatorToThisCall extends JetDelegationSpecifier implements Je
     }
 
     @NotNull
-    public List<JetValueArgument> getValueArguments() {
+    public List<? extends ValueArgument> getValueArguments() {
         JetValueArgumentList list = getValueArgumentList();
         return list != null ? list.getArguments() : Collections.<JetValueArgument>emptyList();
     }
@@ -49,18 +49,17 @@ public class JetDelegatorToThisCall extends JetDelegationSpecifier implements Je
         return Collections.emptyList();
     }
 
-    @NotNull
-    @Override
-    public JetElement asElement() {
-        return this;
-    }
-
     @NotNull
     @Override
     public List<JetTypeProjection> getTypeArguments() {
         return Collections.emptyList();
     }
 
+    @Override
+    public JetTypeArgumentList getTypeArgumentList() {
+        return null;
+    }
+
     public JetReferenceExpression getThisReference() {
         return findChildByClass(JetThisReferenceExpression.class);
     }

idea/src/org/jetbrains/jet/lang/psi/JetNewExpression.java

@@ -3,7 +3,7 @@ package org.jetbrains.jet.lang.psi;
 /**
  * @author max
  */
-//public class JetNewExpression extends JetExpression implements JetCall {
+//public class JetNewExpression extends JetExpression implements JetCallElement {
 //    public JetNewExpression(@NotNull ASTNode node) {
 //        super(node);
 //    }

idea/src/org/jetbrains/jet/lang/psi/JetValueArgument.java

@@ -1,6 +1,7 @@
 package org.jetbrains.jet.lang.psi;
 
 import com.intellij.lang.ASTNode;
+import com.intellij.psi.PsiElement;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.JetNodeTypes;
@@ -9,7 +10,7 @@ import org.jetbrains.jet.lexer.JetTokens;
 /**
  * @author max
  */
-public class JetValueArgument extends JetElement {
+public class JetValueArgument extends JetElement implements ValueArgument {
     public JetValueArgument(@NotNull ASTNode node) {
         super(node);
     }
@@ -23,25 +24,36 @@ public class JetValueArgument extends JetElement {
         return visitor.visitArgument(this, data);
     }
 
+    @Override
     @Nullable @IfNotParsed
     public JetExpression getArgumentExpression() {
         return findChildByClass(JetExpression.class);
     }
 
+    @Override
     @Nullable
     public JetValueArgumentName getArgumentName() {
         return (JetValueArgumentName) findChildByType(JetNodeTypes.VALUE_ARGUMENT_NAME);
     }
 
+    @Override
     public boolean isNamed() {
         return getArgumentName() != null;
     }
 
+    @Override
     public boolean isOut() {
         return findChildByType(JetTokens.OUT_KEYWORD) != null;
     }
 
+    @Override
     public boolean isRef() {
         return findChildByType(JetTokens.REF_KEYWORD) != null;
     }
+
+    @NotNull
+    @Override
+    public PsiElement asElement() {
+        return this;
+    }
 }

idea/src/org/jetbrains/jet/lang/psi/ValueArgument.java

@@ -0,0 +1,27 @@
+package org.jetbrains.jet.lang.psi;
+
+import com.intellij.psi.PsiElement;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * @author abreslav
+ */
+public interface ValueArgument {
+    @Nullable
+    @JetElement.IfNotParsed
+    JetExpression getArgumentExpression();
+
+    @Nullable
+    JetValueArgumentName getArgumentName();
+
+    boolean isNamed();
+
+    boolean isOut();
+
+    boolean isRef();
+
+    @NotNull
+    PsiElement asElement();
+
+}

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

@@ -1,55 +1,48 @@
 package org.jetbrains.jet.lang.resolve;
 
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.jetbrains.jet.lang.types.JetType;
-
-import java.util.List;
-import java.util.Map;
-
 /**
  * @author abreslav
  */
-public interface OverloadDomain {
+//public interface OverloadDomain {
-
+//
-    OverloadDomain EMPTY = new OverloadDomain() {
+//    OverloadDomain EMPTY = new OverloadDomain() {
-        @NotNull
+//        @NotNull
-        @Override
+//        @Override
-        public OverloadResolutionResult getFunctionDescriptorForNamedArguments(@NotNull List<JetType> typeArguments, @NotNull Map<String, JetType> valueArgumentTypes, @Nullable JetType functionLiteralArgumentType) {
+//        public OverloadResolutionResult getFunctionDescriptorForNamedArguments(@NotNull List<JetType> typeArguments, @NotNull Map<String, JetType> valueArgumentTypes, @Nullable JetType functionLiteralArgumentType) {
-            return OverloadResolutionResult.nameNotFound();
+//            return OverloadResolutionResult.nameNotFound();
-        }
+//        }
-
+//
-        @NotNull
+//        @NotNull
-        @Override
+//        @Override
-        public OverloadResolutionResult getFunctionDescriptorForPositionedArguments(@NotNull List<JetType> typeArguments, @NotNull List<JetType> positionedValueArgumentTypes) {
+//        public OverloadResolutionResult getFunctionDescriptorForPositionedArguments(@NotNull List<JetType> typeArguments, @NotNull List<JetType> positionedValueArgumentTypes) {
-            return OverloadResolutionResult.nameNotFound();
+//            return OverloadResolutionResult.nameNotFound();
-        }
+//        }
-
+//
-        @Override
+//        @Override
-        public boolean isEmpty() {
+//        public boolean isEmpty() {
-            return true;
+//            return true;
-        }
+//        }
-    };
+//    };
-
+//
-    /**
+//    /**
-     * @return A function descriptor with NO type parameters (they are already substituted) wrapped together with a result code
+//     * @return A function descriptor with NO type parameters (they are already substituted) wrapped together with a result code
-     */
+//     */
-    @NotNull
+//    @NotNull
-    OverloadResolutionResult getFunctionDescriptorForNamedArguments(
+//    OverloadResolutionResult getFunctionDescriptorForNamedArguments(
-            @NotNull List<JetType> typeArguments,
+//            @NotNull List<JetType> typeArguments,
-            @NotNull Map<String, JetType> valueArgumentTypes,
+//            @NotNull Map<String, JetType> valueArgumentTypes,
-            @Nullable JetType functionLiteralArgumentType);
+//            @Nullable JetType functionLiteralArgumentType);
-
+//
-    /**
+//    /**
-     * @return A function descriptor with NO type parameters (they are already substituted) wrapped together with a result code
+//     * @return A function descriptor with NO type parameters (they are already substituted) wrapped together with a result code
-     */
+//     */
-    @NotNull
+//    @NotNull
-    OverloadResolutionResult getFunctionDescriptorForPositionedArguments(
+//    OverloadResolutionResult getFunctionDescriptorForPositionedArguments(
-            @NotNull List<JetType> typeArguments,
+//            @NotNull List<JetType> typeArguments,
-            @NotNull List<JetType> positionedValueArgumentTypes);
+//            @NotNull List<JetType> positionedValueArgumentTypes);
-
+//
-    /**
+//    /**
-     * @return true if the domain is empty
+//     * @return true if the domain is empty
-     */
+//     */
-    boolean isEmpty();
+//    boolean isEmpty();
-}
+//}

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

@@ -1,173 +1,159 @@
 package org.jetbrains.jet.lang.resolve;
 
-import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
-import org.jetbrains.jet.lang.descriptors.FunctionDescriptor;
-import org.jetbrains.jet.lang.descriptors.FunctionGroup;
-import org.jetbrains.jet.lang.descriptors.ValueParameterDescriptor;
-import org.jetbrains.jet.lang.types.JetType;
-import org.jetbrains.jet.lang.types.JetTypeChecker;
-import org.jetbrains.jet.lang.types.TypeUtils;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-import java.util.Map;
-
 /**
  * @author abreslav
  */
-public class OverloadResolver {
+//public class OverloadResolver {
-
+//
-    private final JetTypeChecker typeChecker;
+//    private final JetTypeChecker typeChecker;
-
+//
-    public OverloadResolver(JetTypeChecker typeChecker) {
+//    public OverloadResolver(JetTypeChecker typeChecker) {
-        this.typeChecker = typeChecker;
+//        this.typeChecker = typeChecker;
-    }
+//    }
-
+//
-    @NotNull
+//    @NotNull
-    public OverloadDomain getOverloadDomain(@Nullable JetType receiverType, @NotNull JetScope outerScope, @NotNull String name) {
+//    public OverloadDomain getOverloadDomain(@Nullable JetType receiverType, @NotNull JetScope outerScope, @NotNull String name) {
-        // TODO : extension lookup
+//        // TODO : extension lookup
-        JetScope scope = receiverType == null ? outerScope : new ScopeWithReceiver(outerScope, receiverType, typeChecker);
+//        JetScope scope = receiverType == null ? outerScope : new ScopeWithReceiver(outerScope, receiverType, typeChecker);
-
+//
-        final FunctionGroup functionGroup = scope.getFunctionGroup(name);
+//        final FunctionGroup functionGroup = scope.getFunctionGroup(name);
-
+//
-        return getOverloadDomain(receiverType, functionGroup);
+//        return getOverloadDomain(receiverType, functionGroup);
-    }
+//    }
-
+//
-    @NotNull
+//    @NotNull
-    public OverloadDomain getOverloadDomain(@Nullable final JetType receiverType, @NotNull final FunctionGroup functionGroup) {
+//    public OverloadDomain getOverloadDomain(@Nullable final JetType receiverType, @NotNull final FunctionGroup functionGroup) {
-        if (functionGroup.isEmpty()) {
+//        if (functionGroup.isEmpty()) {
-            return OverloadDomain.EMPTY;
+//            return OverloadDomain.EMPTY;
-        }
+//        }
-
+//
-        return new OverloadDomain() {
+//        return new OverloadDomain() {
-            @NotNull
+//            @NotNull
-            @Override
+//            @Override
-            public OverloadResolutionResult getFunctionDescriptorForPositionedArguments(@NotNull final List<JetType> typeArguments, @NotNull List<JetType> positionedValueArgumentTypes) {
+//            public OverloadResolutionResult getFunctionDescriptorForPositionedArguments(@NotNull final List<JetType> typeArguments, @NotNull List<JetType> positionedValueArgumentTypes) {
-                OverloadResolutionResult resolutionResult = functionGroup.getPossiblyApplicableFunctions(typeArguments, positionedValueArgumentTypes);
+//                OverloadResolutionResult resolutionResult = functionGroup.getPossiblyApplicableFunctions(typeArguments, positionedValueArgumentTypes);
-                if (!resolutionResult.isAmbiguity() && !resolutionResult.isSuccess()) return resolutionResult;
+//                if (!resolutionResult.isAmbiguity() && !resolutionResult.isSuccess()) return resolutionResult;
-
+//
-                Collection<FunctionDescriptor> possiblyApplicableFunctions = resolutionResult.getFunctionDescriptors();
+//                Collection<FunctionDescriptor> possiblyApplicableFunctions = resolutionResult.getFunctionDescriptors();
-
+//
-                if (possiblyApplicableFunctions.isEmpty()) {
+//                if (possiblyApplicableFunctions.isEmpty()) {
-                    return OverloadResolutionResult.nameNotFound(); // TODO : it may be found, only the number of params did not match
+//                    return OverloadResolutionResult.nameNotFound(); // TODO : it may be found, only the number of params did not match
-                }
+//                }
-
+//
-                List<FunctionDescriptor> applicable = new ArrayList<FunctionDescriptor>();
+//                List<FunctionDescriptor> applicable = new ArrayList<FunctionDescriptor>();
-
+//
-                descLoop:
+//                descLoop:
-                for (FunctionDescriptor descriptor : possiblyApplicableFunctions) {
+//                for (FunctionDescriptor descriptor : possiblyApplicableFunctions) {
-                    // ASSERT: type arguments are figured out and substituted by this time!!!
+//                    // ASSERT: type arguments are figured out and substituted by this time!!!
-                    assert descriptor.getTypeParameters().isEmpty();
+//                    assert descriptor.getTypeParameters().isEmpty();
-
+//
-                    if (receiverType != null) {
+//                    if (receiverType != null) {
-                        // ASSERT : either the receiver in not present or we are in a scope with no top-level functions
+//                        // ASSERT : either the receiver in not present or we are in a scope with no top-level functions
-                        JetType functionReceiverType = descriptor.getReceiverType();
+//                        JetType functionReceiverType = descriptor.getReceiverType();
-                        if (functionReceiverType != null) {
+//                        if (functionReceiverType != null) {
-                            functionReceiverType = TypeUtils.makeNullable(functionReceiverType); // Too look things up in T for T?, and later check receiver's nullability
+//                            functionReceiverType = TypeUtils.makeNullable(functionReceiverType); // Too look things up in T for T?, and later check receiver's nullability
-                            if (!typeChecker.isSubtypeOf(receiverType, functionReceiverType)) {
+//                            if (!typeChecker.isSubtypeOf(receiverType, functionReceiverType)) {
-                                continue;
+//                                continue;
-                            }
+//                            }
-                        }
+//                        }
-                    }
+//                    }
-                    else if (descriptor.getReceiverType() != null) {
+//                    else if (descriptor.getReceiverType() != null) {
-                        continue;
+//                        continue;
-                    }
+//                    }
-
+//
-                    List<ValueParameterDescriptor> parameters = descriptor.getValueParameters();
+//                    List<ValueParameterDescriptor> parameters = descriptor.getValueParameters();
-                    if (parameters.size() >= positionedValueArgumentTypes.size()) {
+//                    if (parameters.size() >= positionedValueArgumentTypes.size()) {
-                        // possibly, some default values
+//                        // possibly, some default values
-                        // possibly, nothing passed to a vararg
+//                        // possibly, nothing passed to a vararg
-                        // possibly, a single value passed to a vararg
+//                        // possibly, a single value passed to a vararg
-                        // possibly an array/list/etc passed as a whole vararg
+//                        // possibly an array/list/etc passed as a whole vararg
-                        for (int i = 0, positionedValueArgumentTypesSize = positionedValueArgumentTypes.size(); i < positionedValueArgumentTypesSize; i++) {
+//                        for (int i = 0, positionedValueArgumentTypesSize = positionedValueArgumentTypes.size(); i < positionedValueArgumentTypesSize; i++) {
-                            JetType argumentType = positionedValueArgumentTypes.get(i);
+//                            JetType argumentType = positionedValueArgumentTypes.get(i);
-                            JetType parameterType = parameters.get(i).getOutType();
+//                            JetType parameterType = parameters.get(i).getOutType();
-                            // TODO : handle vararg cases here
+//                            // TODO : handle vararg cases here
-                            if (!typeChecker.isConvertibleTo(argumentType, parameterType)) {
+//                            if (!typeChecker.isConvertibleTo(argumentType, parameterType)) {
-                                continue descLoop;
+//                                continue descLoop;
-                            }
+//                            }
-                        }
+//                        }
-                    } else {
+//                    } else {
-                        // vararg
+//                        // vararg
-                        int nonVarargs = parameters.size() - 1;
+//                        int nonVarargs = parameters.size() - 1;
-                        for (int i = 0; i < nonVarargs; i++) {
+//                        for (int i = 0; i < nonVarargs; i++) {
-                            JetType argumentType = positionedValueArgumentTypes.get(i);
+//                            JetType argumentType = positionedValueArgumentTypes.get(i);
-                            JetType parameterType = parameters.get(i).getOutType();
+//                            JetType parameterType = parameters.get(i).getOutType();
-                            if (!typeChecker.isConvertibleTo(argumentType, parameterType)) {
+//                            if (!typeChecker.isConvertibleTo(argumentType, parameterType)) {
-                                continue descLoop;
+//                                continue descLoop;
-                            }
+//                            }
-                        }
+//                        }
-                        JetType varArgType = parameters.get(nonVarargs).getOutType();
+//                        JetType varArgType = parameters.get(nonVarargs).getOutType();
-                        for (int i = nonVarargs, args = positionedValueArgumentTypes.size(); i < args; i++) {
+//                        for (int i = nonVarargs, args = positionedValueArgumentTypes.size(); i < args; i++) {
-                            JetType argumentType = positionedValueArgumentTypes.get(i);
+//                            JetType argumentType = positionedValueArgumentTypes.get(i);
-                            if (!typeChecker.isConvertibleTo(argumentType, varArgType)) {
+//                            if (!typeChecker.isConvertibleTo(argumentType, varArgType)) {
-                                continue descLoop;
+//                                continue descLoop;
-                            }
+//                            }
-                        }
+//                        }
-                    }
+//                    }
-                    applicable.add(descriptor);
+//                    applicable.add(descriptor);
-                }
+//                }
-
+//
-                if (applicable.size() == 0) {
+//                if (applicable.size() == 0) {
-                    if (resolutionResult.singleFunction()) {
+//                    if (resolutionResult.singleFunction()) {
-                        return OverloadResolutionResult.singleFunctionArgumentMismatch(resolutionResult.getFunctionDescriptor());
+//                        return OverloadResolutionResult.singleFunctionArgumentMismatch(resolutionResult.getFunctionDescriptor());
-                    }
+//                    }
-                    return OverloadResolutionResult.nameNotFound();
+//                    return OverloadResolutionResult.nameNotFound();
-                } else if (applicable.size() == 1) {
+//                } else if (applicable.size() == 1) {
-                    return OverloadResolutionResult.success(applicable.get(0));
+//                    return OverloadResolutionResult.success(applicable.get(0));
-                } else {
+//                } else {
-                    // TODO : varargs
+//                    // TODO : varargs
-
+//
-                    List<FunctionDescriptor> maximallySpecific = new ArrayList<FunctionDescriptor>();
+//                    List<FunctionDescriptor> maximallySpecific = new ArrayList<FunctionDescriptor>();
-                    meLoop:
+//                    meLoop:
-                    for (FunctionDescriptor me : applicable) {
+//                    for (FunctionDescriptor me : applicable) {
-                        for (FunctionDescriptor other : applicable) {
+//                        for (FunctionDescriptor other : applicable) {
-                            if (other == me) continue;
+//                            if (other == me) continue;
-                            if (!moreSpecific(me, other) || moreSpecific(other, me)) continue meLoop;
+//                            if (!moreSpecific(me, other) || moreSpecific(other, me)) continue meLoop;
-                        }
+//                        }
-                        maximallySpecific.add(me);
+//                        maximallySpecific.add(me);
-                    }
+//                    }
-                    if (maximallySpecific.isEmpty()) {
+//                    if (maximallySpecific.isEmpty()) {
-                        return OverloadResolutionResult.ambiguity(applicable);
+//                        return OverloadResolutionResult.ambiguity(applicable);
-                    }
+//                    }
-                    if (maximallySpecific.size() == 1) {
+//                    if (maximallySpecific.size() == 1) {
-                        return OverloadResolutionResult.success(maximallySpecific.get(0));
+//                        return OverloadResolutionResult.success(maximallySpecific.get(0));
-                    }
+//                    }
-                    throw new UnsupportedOperationException();
+//                    throw new UnsupportedOperationException();
-                }
+//                }
-            }
+//            }
-
+//
-            @Override
+//            @Override
-            public boolean isEmpty() {
+//            public boolean isEmpty() {
-                return functionGroup.isEmpty();
+//                return functionGroup.isEmpty();
-            }
+//            }
-
+//
-            @NotNull
+//            @NotNull
-            @Override
+//            @Override
-            public OverloadResolutionResult getFunctionDescriptorForNamedArguments(@NotNull List<JetType> typeArguments, @NotNull Map<String, JetType> valueArgumentTypes, @Nullable JetType functionLiteralArgumentType) {
+//            public OverloadResolutionResult getFunctionDescriptorForNamedArguments(@NotNull List<JetType> typeArguments, @NotNull Map<String, JetType> valueArgumentTypes, @Nullable JetType functionLiteralArgumentType) {
-                throw new UnsupportedOperationException(); // TODO
+//                throw new UnsupportedOperationException(); // TODO
-            }
+//            }
-        };
+//        };
-    }
+//    }
-
+//
-    private boolean moreSpecific(FunctionDescriptor f, FunctionDescriptor g) {
+//    private boolean moreSpecific(FunctionDescriptor f, FunctionDescriptor g) {
-        List<ValueParameterDescriptor> fParams = f.getValueParameters();
+//        List<ValueParameterDescriptor> fParams = f.getValueParameters();
-        List<ValueParameterDescriptor> gParams = g.getValueParameters();
+//        List<ValueParameterDescriptor> gParams = g.getValueParameters();
-
+//
-        int fSize = fParams.size();
+//        int fSize = fParams.size();
-        if (fSize != gParams.size()) return false;
+//        if (fSize != gParams.size()) return false;
-        for (int i = 0; i < fSize; i++) {
+//        for (int i = 0; i < fSize; i++) {
-            JetType fParamType = fParams.get(i).getOutType();
+//            JetType fParamType = fParams.get(i).getOutType();
-            JetType gParamType = gParams.get(i).getOutType();
+//            JetType gParamType = gParams.get(i).getOutType();
-
+//
-            // TODO : maybe isSubtypeOf is sufficient?
+//            // TODO : maybe isSubtypeOf is sufficient?
-            if (!typeChecker.isConvertibleTo(fParamType, gParamType)) {
+//            if (!typeChecker.isConvertibleTo(fParamType, gParamType)) {
-                return false;
+//                return false;
-            }
+//            }
-        }
+//        }
-        return true;
+//        return true;
-    }
+//    }
-
+//
-}
+//}

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

@@ -94,7 +94,9 @@ public class SubstitutingScope implements JetScope {
         if (allDescriptors == null) {
             allDescriptors = Sets.newHashSet();
             for (DeclarationDescriptor descriptor : workerScope.getAllDescriptors()) {
-                allDescriptors.add(descriptor.substitute(substitutor));
+                DeclarationDescriptor substitute = descriptor.substitute(substitutor);
+                assert substitute != null;
+                allDescriptors.add(substitute);
             }
         }
         return allDescriptors;

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

@@ -11,15 +11,14 @@ import org.jetbrains.jet.lang.cfg.JetFlowInformationProvider;
 import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.descriptors.annotations.AnnotationDescriptor;
 import org.jetbrains.jet.lang.psi.*;
-import org.jetbrains.jet.lang.types.ErrorUtils;
+import org.jetbrains.jet.lang.types.*;
-import org.jetbrains.jet.lang.types.JetStandardClasses;
-import org.jetbrains.jet.lang.types.JetType;
-import org.jetbrains.jet.lang.types.JetTypeInferrer;
 import org.jetbrains.jet.lexer.JetTokens;
 import org.jetbrains.jet.util.WritableSlice;
 
 import java.util.*;
 
+import static org.jetbrains.jet.lang.types.JetTypeInferrer.NO_EXPECTED_TYPE;
+
 /**
  * @author abreslav
  */
@@ -568,7 +567,7 @@ public class TopDownAnalyzer {
                     JetExpression delegateExpression = specifier.getDelegateExpression();
                     if (delegateExpression != null) {
                         JetScope scope = scopeForConstructor == null ? descriptor.getScopeForMemberResolution() : scopeForConstructor;
-                        JetType type = typeInferrer.getType(scope, delegateExpression, false, JetTypeInferrer.NO_EXPECTED_TYPE);
+                        JetType type = typeInferrer.getType(scope, delegateExpression, false, NO_EXPECTED_TYPE);
                         JetType supertype = trace.getBindingContext().get(BindingContext.TYPE, specifier.getTypeReference());
                         if (type != null && !semanticServices.getTypeChecker().isSubtypeOf(type, supertype)) { // TODO : Convertible?
                             trace.getErrorHandler().typeMismatch(delegateExpression, supertype, type);
@@ -581,7 +580,7 @@ public class TopDownAnalyzer {
                     JetTypeReference typeReference = call.getTypeReference();
                     if (typeReference != null) {
                         if (descriptor.getUnsubstitutedPrimaryConstructor() != null) {
-                            typeInferrer.checkTypeInitializerCall(scopeForConstructor, typeReference, call);
+                            typeInferrer.getCallResolver().resolveCall(scopeForConstructor, call, NO_EXPECTED_TYPE);
                         }
                         else {
                             JetValueArgumentList valueArgumentList = call.getValueArgumentList();
@@ -644,7 +643,7 @@ public class TopDownAnalyzer {
             final JetScope scopeForConstructor = getInnerScopeForConstructor(primaryConstructor, classDescriptor.getScopeForMemberResolution(), true);
             JetTypeInferrer.Services typeInferrer = semanticServices.getTypeInferrerServices(traceForConstructors, JetFlowInformationProvider.NONE); // TODO : flow
             for (JetClassInitializer anonymousInitializer : anonymousInitializers) {
-                typeInferrer.getType(scopeForConstructor, anonymousInitializer.getBody(), true, JetTypeInferrer.NO_EXPECTED_TYPE);
+                typeInferrer.getType(scopeForConstructor, anonymousInitializer.getBody(), true, NO_EXPECTED_TYPE);
             }
         }
         else {
@@ -686,7 +685,7 @@ public class TopDownAnalyzer {
                     public void visitDelegationToSuperCallSpecifier(JetDelegatorToSuperCall call) {
                         JetTypeReference typeReference = call.getTypeReference();
                         if (typeReference != null) {
-                            typeInferrerForInitializers.checkTypeInitializerCall(functionInnerScope, typeReference, call);
+                            typeInferrerForInitializers.getCallResolver().resolveCall(functionInnerScope, call, NO_EXPECTED_TYPE);
                         }
                     }
 
@@ -694,13 +693,14 @@ public class TopDownAnalyzer {
                     public void visitDelegationToThisCall(JetDelegatorToThisCall call) {
                         // TODO : check that there's no recursion in this() calls
                         // TODO : check: if a this() call is present, no other initializers are allowed
-                        ClassDescriptor classDescriptor = descriptor.getContainingDeclaration();
+//                        ClassDescriptor classDescriptor = descriptor.getContainingDeclaration();
-                        typeInferrerForInitializers.checkClassConstructorCall(
+//                        typeInferrerForInitializers.checkClassConstructorCall(
-                                functionInnerScope,
+//                                functionInnerScope,
-                                call.getThisReference(),
+//                                call.getThisReference(),
-                                classDescriptor,
+//                                classDescriptor,
-                                classDescriptor.getDefaultType(),
+//                                classDescriptor.getDefaultType(),
-                                call);
+//                                call);
+                        trace.getErrorHandler().genericError(call.getNode(), "this-calls are not supported");
                     }
 
                     @Override
@@ -859,7 +859,7 @@ public class TopDownAnalyzer {
     private void resolvePropertyInitializer(JetProperty property, PropertyDescriptor propertyDescriptor, JetExpression initializer, JetScope scope) {
         JetFlowInformationProvider flowInformationProvider = classDescriptorResolver.computeFlowData(property, initializer); // TODO : flow JET-15
         JetTypeInferrer.Services typeInferrer = semanticServices.getTypeInferrerServices(traceForConstructors, flowInformationProvider);
-        JetType type = typeInferrer.getType(getPropertyDeclarationInnerScope(scope, propertyDescriptor), initializer, false, JetTypeInferrer.NO_EXPECTED_TYPE);
+        JetType type = typeInferrer.getType(getPropertyDeclarationInnerScope(scope, propertyDescriptor), initializer, false, NO_EXPECTED_TYPE);
 
         JetType expectedType;
         PropertySetterDescriptor setter = propertyDescriptor.getSetter();

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

@@ -0,0 +1,117 @@
+package org.jetbrains.jet.lang.types;
+
+import com.google.common.collect.Lists;
+import com.intellij.psi.PsiElement;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jet.lang.psi.*;
+
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * @author abreslav
+ */
+public class CallMaker {
+
+    private static class ExpressionValueArgument implements ValueArgument {
+
+        private final JetExpression expression;
+
+        private ExpressionValueArgument(JetExpression expression) {
+            this.expression = expression;
+        }
+
+        @Override
+        public JetExpression getArgumentExpression() {
+            return expression;
+        }
+
+        @Override
+        public JetValueArgumentName getArgumentName() {
+            return null;
+        }
+
+        @Override
+        public boolean isNamed() {
+            return false;
+        }
+
+        @Override
+        public boolean isOut() {
+            return false;
+        }
+
+        @Override
+        public boolean isRef() {
+            return false;
+        }
+
+        @NotNull
+        @Override
+        public PsiElement asElement() {
+            return expression;
+        }
+    }
+
+    private static abstract class CallStub implements Call {
+        @Override
+        public JetValueArgumentList getValueArgumentList() {
+            return null;
+        }
+
+        @NotNull
+        @Override
+        public List<JetExpression> getFunctionLiteralArguments() {
+            return Collections.emptyList();
+        }
+
+        @NotNull
+        @Override
+        public List<JetTypeProjection> getTypeArguments() {
+            return Collections.emptyList();
+        }
+
+        @Override
+        public JetTypeArgumentList getTypeArgumentList() {
+            return null;
+        }
+    }
+
+    public static Call makeCallWithArguments(final JetExpression calleeExpression, final List<? extends ValueArgument> valueArguments) {
+        return new CallStub() {
+            @Override
+            public JetExpression getCalleeExpression() {
+                return calleeExpression;
+            }
+
+            @NotNull
+            @Override
+            public List<? extends ValueArgument> getValueArguments() {
+                return valueArguments;
+            }
+        };
+    }
+
+    public static Call makeCall(final JetExpression calleeExpression, final List<JetExpression> argumentExpressions) {
+        List<ExpressionValueArgument> arguments = Lists.newArrayList();
+        for (JetExpression argumentExpression : argumentExpressions) {
+            arguments.add(new ExpressionValueArgument(argumentExpression));
+        }
+        return makeCallWithArguments(calleeExpression, arguments);
+    }
+
+    public static Call makeCall(final JetBinaryExpression expression) {
+        return makeCall(expression.getOperationReference(), Collections.singletonList(expression.getRight()));
+    }
+
+    public static Call makeCall(final JetUnaryExpression expression) {
+        return makeCallWithArguments(expression.getOperationSign(), Collections.<ValueArgument>emptyList());
+    }
+
+    public static Call makeCall(final JetArrayAccessExpression arrayAccessExpression, final JetExpression rightHandSide) {
+        List<JetExpression> arguments = Lists.newArrayList(arrayAccessExpression.getIndexExpressions());
+        arguments.add(rightHandSide);
+        return makeCall(arrayAccessExpression, arguments);
+    }
+
+}

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

@@ -0,0 +1,515 @@
+package org.jetbrains.jet.lang.types;
+
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import com.intellij.lang.ASTNode;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.jetbrains.jet.lang.JetSemanticServices;
+import org.jetbrains.jet.lang.descriptors.*;
+import org.jetbrains.jet.lang.psi.*;
+import org.jetbrains.jet.lang.resolve.*;
+import org.jetbrains.jet.lang.types.inference.ConstraintSystem;
+import org.jetbrains.jet.resolve.DescriptorRenderer;
+
+import java.util.*;
+
+import static org.jetbrains.jet.lang.resolve.BindingContext.REFERENCE_TARGET;
+import static org.jetbrains.jet.lang.types.JetTypeInferrer.NO_EXPECTED_TYPE;
+
+/**
+ * @author abreslav
+ */
+public class CallResolver {
+
+    private static abstract class ResolutionTask {
+        private final Collection<FunctionDescriptor> candidates;
+        private final JetExpression receiver;
+        private final List<JetTypeProjection> typeArguments;
+        private final List<? extends ValueArgument> valueArguments;
+
+        protected ResolutionTask(
+                @NotNull Collection<FunctionDescriptor> candidates,
+                @Nullable JetExpression receiver,
+                @NotNull List<JetTypeProjection> typeArguments,
+                @NotNull List<? extends ValueArgument> valueArguments) {
+            this.candidates = candidates;
+            this.receiver = receiver;
+            this.typeArguments = typeArguments;
+            this.valueArguments = valueArguments;
+        }
+
+        @NotNull
+        public Collection<FunctionDescriptor> getCandidates() {
+            return candidates;
+        }
+
+        @Nullable
+        public JetExpression getReceiver() {
+            return receiver;
+        }
+
+        @NotNull
+        public List<JetTypeProjection> getTypeArguments() {
+            return typeArguments;
+        }
+        
+        @NotNull
+        public List<? extends ValueArgument> getValueArguments() {
+            return valueArguments;
+        }
+
+        public abstract void bindFunctionReference(@NotNull BindingTrace trace, @NotNull FunctionDescriptor functionDescriptor);
+
+        public abstract void reportOverallResolutionError(@NotNull BindingTrace trace, @NotNull String message);
+
+        public abstract void reportWrongTypeArguments(@NotNull BindingTrace trace, @NotNull String message);
+
+        public abstract void reportWrongValueArguments(@NotNull BindingTrace trace, @NotNull String message);
+
+        public abstract void reportUnresolvedFunctionReference(@NotNull BindingTrace trace);
+    }
+
+    private final BindingTrace trace;
+    private final TypeResolver typeResolver;
+    private final JetTypeInferrer typeInferrer;
+    private final JetSemanticServices semanticServices;
+    private final ClassDescriptorResolver classDescriptorResolver;
+
+    public CallResolver(JetSemanticServices semanticServices, BindingTrace trace, JetTypeInferrer typeInferrer) {
+        this.trace = trace;
+        this.typeInferrer = typeInferrer;
+        this.typeResolver = new TypeResolver(semanticServices, trace, true);
+        this.classDescriptorResolver = semanticServices.getClassDescriptorResolver(trace);
+        this.semanticServices = semanticServices;
+    }
+
+    @Nullable
+    public JetType resolveCall(
+            @NotNull JetScope scope,
+            @NotNull JetCallElement call,
+            @NotNull JetType expectedType
+    ) {
+        FunctionDescriptor functionDescriptor = resolveSimpleCallToFunctionDescriptor(scope, null, call, expectedType);
+        return functionDescriptor == null ? null : functionDescriptor.getReturnType();
+    }
+    
+    @Nullable
+    public FunctionDescriptor resolveCallWithGivenName(
+            @NotNull JetScope scope,
+            @NotNull final Call call,
+            @NotNull final JetReferenceExpression functionReference,
+            @NotNull String name,
+            @Nullable JetExpression receiver,
+            @NotNull JetType expectedType) {
+        Collection<FunctionDescriptor> candidates;
+        if (receiver != null) {
+            JetType type = typeInferrer.getServices(trace).getType(scope, receiver, false, NO_EXPECTED_TYPE);
+            if (type == null) {
+                return null; // TODO : check parameter types anyway?
+            }
+            // TODO : autocasts
+            // TODO : nullability
+            candidates = type.getMemberScope().getFunctionGroup(name).getFunctionDescriptors();
+        }
+        else {
+            candidates = scope.getFunctionGroup(name).getFunctionDescriptors();
+        }
+        return resolveCallToFunctionDescriptor(scope, receiver, call, functionReference.getNode(), expectedType, candidates, functionReference);
+    }
+
+    @Nullable
+    public FunctionDescriptor resolveSimpleCallToFunctionDescriptor(
+            @NotNull JetScope scope,
+            @Nullable JetExpression receiver,
+            @NotNull final JetCallElement call,
+            @NotNull JetType expectedType
+    ) {
+        JetExpression calleeExpression = call.getCalleeExpression();
+        Collection<FunctionDescriptor> candidates;
+        final JetReferenceExpression functionReference;
+        if (calleeExpression instanceof JetSimpleNameExpression) {
+            JetSimpleNameExpression expression = (JetSimpleNameExpression) calleeExpression;
+            functionReference = expression;
+            candidates = scope.getFunctionGroup(expression.getReferencedName()).getFunctionDescriptors();
+        }
+        else if (calleeExpression instanceof JetConstructorCalleeExpression) {
+            JetConstructorCalleeExpression expression = (JetConstructorCalleeExpression) calleeExpression;
+            functionReference = expression.getConstructorReferenceExpression();
+            JetType constructedType = typeResolver.resolveType(scope, expression.getTypeReference());
+            DeclarationDescriptor declarationDescriptor = constructedType.getConstructor().getDeclarationDescriptor();
+            if (declarationDescriptor instanceof ClassDescriptor) {
+                ClassDescriptor classDescriptor = (ClassDescriptor) declarationDescriptor;
+                candidates = classDescriptor.getConstructors().getFunctionDescriptors();
+            }
+            else {
+                trace.getErrorHandler().genericError(calleeExpression.getNode(), "Not a class");
+                return null;
+            }
+        }
+        else {
+            throw new UnsupportedOperationException("Type argument inference not implemented");
+        }
+
+        return resolveCallToFunctionDescriptor(scope, receiver, call, call.getNode(), expectedType, candidates, functionReference);
+    }
+
+
+    private FunctionDescriptor resolveCallToFunctionDescriptor(
+            JetScope scope,
+            final JetExpression receiver,
+            final Call call,
+            final ASTNode callNode,
+            JetType expectedType,
+            final Collection<FunctionDescriptor> candidates,
+            final JetReferenceExpression functionReference) {
+        ResolutionTask task = new ResolutionTask(candidates, receiver, call.getTypeArguments(), call.getValueArguments()) {
+            @Override
+            public void bindFunctionReference(@NotNull BindingTrace trace, @NotNull FunctionDescriptor functionDescriptor) {
+                trace.record(BindingContext.REFERENCE_TARGET, functionReference, functionDescriptor);
+            }
+
+            @Override
+            public void reportOverallResolutionError(@NotNull BindingTrace trace, @NotNull String message) {
+                trace.getErrorHandler().genericError(callNode, message);
+            }
+
+            @Override
+            public void reportWrongTypeArguments(@NotNull BindingTrace trace, @NotNull String message) {
+                JetTypeArgumentList typeArgumentList = call.getTypeArgumentList();
+                if (typeArgumentList != null) {
+                    trace.getErrorHandler().genericError(typeArgumentList.getNode(), message);
+                }
+                else {
+                    reportOverallResolutionError(trace, message);
+                }
+            }
+
+            @Override
+            public void reportWrongValueArguments(@NotNull BindingTrace trace, @NotNull String message) {
+                ASTNode node;
+
+                JetValueArgumentList valueArgumentList = call.getValueArgumentList();
+                if (valueArgumentList != null) {
+                    node = valueArgumentList.getNode();
+                }
+                else if (!call.getFunctionLiteralArguments().isEmpty()) {
+                    node = call.getFunctionLiteralArguments().get(0).getNode();
+                }
+                else {
+                    node = callNode;
+                }
+
+                trace.getErrorHandler().genericError(node, message);
+            }
+
+            @Override
+            public void reportUnresolvedFunctionReference(@NotNull BindingTrace trace) {
+                trace.getErrorHandler().unresolvedReference(functionReference);
+            }
+        };
+        return performResolution(scope, expectedType, task);
+    }
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+    private boolean mapValueArgumentsToParameters(
+            @NotNull ResolutionTask task,
+            @NotNull FunctionDescriptor candidate,
+            @NotNull BindingTrace temporaryTrace,
+            @NotNull Map<ValueArgument, ValueParameterDescriptor> argumentsToParameters
+    ) {
+        Set<ValueParameterDescriptor> usedParameters = Sets.newHashSet();
+
+        List<ValueParameterDescriptor> valueParameters = candidate.getValueParameters();
+        Map<String, ValueParameterDescriptor> parameterByName = Maps.newHashMap();
+        for (ValueParameterDescriptor valueParameter : valueParameters) {
+            parameterByName.put(valueParameter.getName(), valueParameter);
+        }
+
+        List<? extends ValueArgument> valueArguments = task.getValueArguments();
+
+        boolean someNamed = false;
+        boolean somePositioned = false;
+        boolean error = false;
+        for (int i = 0; i < valueArguments.size(); i++) {
+            ValueArgument valueArgument = valueArguments.get(i);
+            if (valueArgument.isNamed()) {
+                someNamed = true;
+                if (somePositioned) {
+                    temporaryTrace.getErrorHandler().genericError(valueArgument.getArgumentName().getNode(), "Mixing named and positioned arguments in not allowed");
+                    error = true;
+                }
+                else {
+                    ValueParameterDescriptor valueParameterDescriptor = parameterByName.get(valueArgument.getArgumentName().getName());
+                    usedParameters.add(valueParameterDescriptor);
+                    if (valueParameterDescriptor == null) {
+                        temporaryTrace.getErrorHandler().genericError(valueArgument.getArgumentName().getNode(), "Cannot find a parameter with this name");
+                        error = true;
+                    }
+                    else {
+                        temporaryTrace.record(REFERENCE_TARGET, valueArgument.getArgumentName().getReferenceExpression(), valueParameterDescriptor);
+                        argumentsToParameters.put(valueArgument, valueParameterDescriptor);
+                    }
+                }
+            }
+            else {
+                somePositioned = true;
+                if (someNamed) {
+                    temporaryTrace.getErrorHandler().genericError(valueArgument.asElement().getNode(), "Mixing named and positioned arguments in not allowed");
+                    error = true;
+                }
+                else {
+                    if (i < valueParameters.size()) {
+                        ValueParameterDescriptor valueParameterDescriptor = valueParameters.get(i);
+                        usedParameters.add(valueParameterDescriptor);
+                        argumentsToParameters.put(valueArgument, valueParameterDescriptor);
+                    }
+                    else if (!valueParameters.isEmpty()) {
+
+                        ValueParameterDescriptor valueParameterDescriptor = valueParameters.get(valueParameters.size() - 1);
+                        if (valueParameterDescriptor.isVararg()) {
+                            argumentsToParameters.put(valueArgument, valueParameterDescriptor);
+                            usedParameters.add(valueParameterDescriptor);
+                        }
+                        else {
+                            temporaryTrace.getErrorHandler().genericError(valueArgument.asElement().getNode(), "Too many arguments");
+                            error = true;
+                        }
+                    }
+                    else {
+                        temporaryTrace.getErrorHandler().genericError(valueArgument.asElement().getNode(), "Too many arguments");
+                        error = true;
+                    }
+                }
+            }
+        }
+
+        for (ValueParameterDescriptor valueParameter : valueParameters) {
+            if (!usedParameters.contains(valueParameter)) {
+                if (!valueParameter.hasDefaultValue()) {
+                    task.reportWrongValueArguments(temporaryTrace, "No value passed for parameter " + valueParameter.getName());
+                    error = true;
+                }
+            }
+        }
+        return error;
+    }
+
+    @Nullable
+    private FunctionDescriptor performResolution(@NotNull JetScope scope, @NotNull JetType expectedType, @NotNull ResolutionTask task) {
+        Map<FunctionDescriptor, FunctionDescriptor> successfulCandidates = Maps.newHashMap();
+        Set<FunctionDescriptor> failedCandidates = Sets.newHashSet();
+        Map<FunctionDescriptor, ConstraintSystem.Solution> solutions = Maps.newHashMap();
+        Map<FunctionDescriptor, TemporaryBindingTrace> traces = Maps.newHashMap();
+
+        for (FunctionDescriptor candidate : task.getCandidates()) {
+            TemporaryBindingTrace temporaryTrace = new TemporaryBindingTrace(trace.getBindingContext());
+            traces.put(candidate, temporaryTrace);
+            JetTypeInferrer.Services temporaryServices = typeInferrer.getServices(temporaryTrace);
+
+            task.bindFunctionReference(temporaryTrace, candidate);
+
+            Map<ValueArgument, ValueParameterDescriptor> argumentsToParameters = Maps.newHashMap();
+            boolean error = mapValueArgumentsToParameters(task, candidate, temporaryTrace, argumentsToParameters);
+
+            if (error) continue;
+
+            if (task.getTypeArguments().isEmpty()) {
+                // Type argument inference
+
+                ConstraintSystem constraintSystem = new ConstraintSystem();
+                for (TypeParameterDescriptor typeParameterDescriptor : candidate.getTypeParameters()) {
+                    constraintSystem.registerTypeVariable(typeParameterDescriptor, Variance.INVARIANT); // TODO
+                }
+
+                for (Map.Entry<ValueArgument, ValueParameterDescriptor> entry : argumentsToParameters.entrySet()) {
+                    ValueArgument valueArgument = entry.getKey();
+                    ValueParameterDescriptor valueParameterDescriptor = entry.getValue();
+
+                    JetExpression expression = valueArgument.getArgumentExpression();
+                    // TODO : more attempts, with different expected types
+                    JetType type = temporaryServices.getType(scope, expression, false, NO_EXPECTED_TYPE);
+                    if (type != null) {
+                        constraintSystem.addSubtypingConstraint(type, valueParameterDescriptor.getOutType());
+                    }
+                }
+
+                if (expectedType != NO_EXPECTED_TYPE) {
+                    constraintSystem.addSubtypingConstraint(candidate.getReturnType(), expectedType);
+                }
+
+                ConstraintSystem.Solution solution = constraintSystem.solve();
+                solutions.put(candidate, solution);
+                if (solution.isSuccessful()) {
+                    FunctionDescriptor substitute = candidate.substitute(solution.getSubstitutor());
+                    assert substitute != null;
+                    successfulCandidates.put(candidate, substitute);
+                }
+                else {
+                    task.reportOverallResolutionError(temporaryTrace, "Type inference failed");
+                    failedCandidates.add(candidate);
+                }
+            }
+            else {
+                // Explicit type arguments passed
+
+                final List<JetTypeProjection> jetTypeArguments = task.getTypeArguments();
+
+                for (JetTypeProjection typeArgument : jetTypeArguments) {
+                    if (typeArgument.getProjectionKind() != JetProjectionKind.NONE) {
+                        temporaryTrace.getErrorHandler().genericError(typeArgument.getNode(), "Projections are not allowed on type parameters for methods"); // TODO : better positioning
+                    }
+                }
+
+                List<JetType> typeArguments = new ArrayList<JetType>();
+                for (JetTypeProjection projection : jetTypeArguments) {
+                    // TODO : check that there's no projection
+                    JetTypeReference typeReference = projection.getTypeReference();
+                    if (typeReference != null) {
+                        typeArguments.add(new TypeResolver(semanticServices, temporaryTrace, true).resolveType(scope, typeReference));
+                    }
+                }
+
+                checkGenericBoundsInAFunctionCall(jetTypeArguments, typeArguments, candidate);
+
+                int typeArgCount = typeArguments.size();
+                if (candidate.getTypeParameters().size() == typeArgCount) {
+                    FunctionDescriptor substitutedFunctionDescriptor = FunctionDescriptorUtil.substituteFunctionDescriptor(typeArguments, candidate);
+
+                    assert substitutedFunctionDescriptor != null;
+                    Map<ValueParameterDescriptor, ValueParameterDescriptor> parameterMap = Maps.newHashMap();
+                    for (ValueParameterDescriptor valueParameterDescriptor : substitutedFunctionDescriptor.getValueParameters()) {
+                        parameterMap.put(valueParameterDescriptor.getOriginal(), valueParameterDescriptor);
+                    }
+
+                    boolean localError = false;
+                    for (Map.Entry<ValueArgument, ValueParameterDescriptor> entry : argumentsToParameters.entrySet()) {
+                        ValueArgument valueArgument = entry.getKey();
+                        ValueParameterDescriptor valueParameterDescriptor = entry.getValue();
+
+                        ValueParameterDescriptor substitutedParameter = parameterMap.get(valueParameterDescriptor.getOriginal());
+
+                        assert substitutedParameter != null;
+
+                        JetType parameterType = substitutedParameter.getOutType();
+                        JetType type = temporaryServices.getType(scope, valueArgument.getArgumentExpression(), false, parameterType);
+                        if (type == null) {
+                            localError = true;
+                        }
+                    }
+                    if (localError) {
+                        failedCandidates.add(candidate);
+                    }
+                    else {
+                        successfulCandidates.put(candidate, substitutedFunctionDescriptor);
+                    }
+
+                }
+                else {
+                    failedCandidates.add(candidate);
+                    task.reportWrongTypeArguments(temporaryTrace, "Number of type arguments does not match " + DescriptorRenderer.TEXT.render(candidate));
+                }
+            }
+        }
+
+        if (successfulCandidates.size() > 0) {
+            if (successfulCandidates.size() == 1) {
+                Map.Entry<FunctionDescriptor, FunctionDescriptor> entry = successfulCandidates.entrySet().iterator().next();
+                FunctionDescriptor functionDescriptor = entry.getKey();
+                FunctionDescriptor result = entry.getValue();
+
+                TemporaryBindingTrace temporaryTrace = traces.get(functionDescriptor);
+                temporaryTrace.addAllMyDataTo(trace);
+                return result;
+            }
+            else {
+                Map<FunctionDescriptor, TemporaryBindingTrace> maximallySpecific = Maps.newHashMap();
+                meLoop:
+                for (Map.Entry<FunctionDescriptor, FunctionDescriptor> myEntry : successfulCandidates.entrySet()) {
+                    FunctionDescriptor me = myEntry.getValue();
+                    TemporaryBindingTrace myTrace = traces.get(myEntry.getKey());
+                    for (FunctionDescriptor other : successfulCandidates.values()) {
+                        if (other == me) continue;
+                        if (!moreSpecific(me, other) || moreSpecific(other, me)) continue meLoop;
+                    }
+                    maximallySpecific.put(me, myTrace);
+                }
+                if (maximallySpecific.size() == 1) {
+                    Map.Entry<FunctionDescriptor, TemporaryBindingTrace> result = maximallySpecific.entrySet().iterator().next();
+                    result.getValue().addAllMyDataTo(trace);
+                    return result.getKey();
+                }
+
+                StringBuilder stringBuilder = new StringBuilder();
+                for (FunctionDescriptor functionDescriptor : successfulCandidates.keySet()) {
+                    stringBuilder.append(DescriptorRenderer.TEXT.render(functionDescriptor)).append(" ");
+                }
+
+                task.reportOverallResolutionError(trace, "Overload resolution ambiguity: " + stringBuilder);
+            }
+        }
+        else if (!failedCandidates.isEmpty()) {
+            if (failedCandidates.size() == 1) {
+                FunctionDescriptor functionDescriptor = failedCandidates.iterator().next();
+                TemporaryBindingTrace temporaryTrace = traces.get(functionDescriptor);
+                temporaryTrace.addAllMyDataTo(trace);
+            }
+            else {
+                StringBuilder stringBuilder = new StringBuilder();
+                for (FunctionDescriptor functionDescriptor : failedCandidates) {
+                    stringBuilder.append(DescriptorRenderer.TEXT.render(functionDescriptor)).append(" ");
+                }
+
+                task.reportOverallResolutionError(trace, "None of the following functions can be called with the arguments supplied: " + stringBuilder);
+            }
+        }
+        else {
+            task.reportUnresolvedFunctionReference(trace);
+        }
+        return null;
+    }
+
+    private boolean moreSpecific(FunctionDescriptor f, FunctionDescriptor g) {
+        List<ValueParameterDescriptor> fParams = f.getValueParameters();
+        List<ValueParameterDescriptor> gParams = g.getValueParameters();
+
+        int fSize = fParams.size();
+        if (fSize != gParams.size()) return false;
+        for (int i = 0; i < fSize; i++) {
+            JetType fParamType = fParams.get(i).getOutType();
+            JetType gParamType = gParams.get(i).getOutType();
+
+            if (!JetTypeChecker.INSTANCE.isSubtypeOf(fParamType, gParamType)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public void checkGenericBoundsInAFunctionCall(List<JetTypeProjection> jetTypeArguments, List<JetType> typeArguments, FunctionDescriptor functionDescriptor) {
+        Map<TypeConstructor, TypeProjection> context = Maps.newHashMap();
+
+        List<TypeParameterDescriptor> typeParameters = functionDescriptor.getOriginal().getTypeParameters();
+        for (int i = 0, typeParametersSize = typeParameters.size(); i < typeParametersSize; i++) {
+            TypeParameterDescriptor typeParameter = typeParameters.get(i);
+            JetType typeArgument = typeArguments.get(i);
+            context.put(typeParameter.getTypeConstructor(), new TypeProjection(typeArgument));
+        }
+        TypeSubstitutor substitutor = TypeSubstitutor.create(context);
+        for (int i = 0, typeParametersSize = typeParameters.size(); i < typeParametersSize; i++) {
+            TypeParameterDescriptor typeParameterDescriptor = typeParameters.get(i);
+            JetType typeArgument = typeArguments.get(i);
+            JetTypeReference typeReference = jetTypeArguments.get(i).getTypeReference();
+            assert typeReference != null;
+            classDescriptorResolver.checkBounds(typeReference, typeArgument, typeParameterDescriptor, substitutor);
+        }
+    }
+
+    @NotNull
+    public OverloadResolutionResult resolveExactSignature(@NotNull JetScope scope, @NotNull JetType receiver, @NotNull String name, @NotNull List<JetType> jetTypes) {
+        // TODO
+        return OverloadResolutionResult.nameNotFound();
+    }
+
+}

idea/src/org/jetbrains/jet/lang/types/inference/ConstraintSystem.java

@@ -194,12 +194,12 @@ public class ConstraintSystem {
     private UnknownType getTypeVariable(TypeParameterDescriptor typeParameterDescriptor) {
         UnknownType unknownType = unknownTypes.get(typeParameterDescriptor);
         if (unknownType == null) {
-            throw new IllegalArgumentException("This type parameter is not an unknown in this constraint system");
+            throw new IllegalArgumentException("This type parameter is not an unknown in this constraint system: " + typeParameterDescriptor);
         }
         return unknownType;
     }
 
-    public void addSubtypingConstraint(JetType lower, JetType upper) {
+    public void addSubtypingConstraint(@NotNull JetType lower, @NotNull JetType upper) {
         TypeValue typeValueForLower = getTypeValueFor(lower);
         TypeValue typeValueForUpper = getTypeValueFor(upper);
         addSubtypingConstraintOnTypeValues(typeValueForLower, typeValueForUpper);