Contains (in, !in)

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

@@ -62,7 +62,7 @@ public class JavaClassMembersScope implements JetScope {
     @Override
     public FunctionGroup getFunctionGroup(@NotNull String name) {
         WritableFunctionGroup writableFunctionGroup = new WritableFunctionGroup(name);
-        PsiMethod[] allMethods = psiClass.getAllMethods();
+        PsiMethod[] allMethods = psiClass.getMethods(); // TODO : look into superclasses
         for (PsiMethod method : allMethods) {
             if (method.hasModifierProperty(PsiModifier.STATIC) != staticMembers) {
                 continue;

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

@@ -601,22 +601,39 @@ public class JetTypeInferrer {
                 }
             }
             else if (equalsOperations.contains(operationType)) {
-                JetType equalsType = getTypeForBinaryCall(expression, "equals", scope, true);
-                if (equalsType != null) {
-                    // TODO : Relax?
-                    TypeConstructor booleanTypeConstructor = semanticServices.getStandardLibrary().getBoolean().getTypeConstructor();
-                    if (!equalsType.getConstructor().equals(booleanTypeConstructor)) {
-                        semanticServices.getErrorHandler().structuralError(operationSign.getNode(), "'equals' must return Boolean but returns " + equalsType);
-                    } else {
-                        result = equalsType;
-                    }
+                String name = "equals";
+                JetType equalsType = getTypeForBinaryCall(expression, name, scope, true);
+                assureBooleanResult(operationSign, name, equalsType);
+            }
+            else if (inOperations.contains(operationType)) {
+                JetExpression right = expression.getRight();
+                if (right == null) {
+                    result = ErrorType.createErrorType("No right argument"); // TODO
+                    return;
                 }
+                String name = "contains";
+                JetType containsType = getTypeForBinaryCall(scope, right, expression.getOperationReference(), expression.getLeft(), name, true);
+                result = assureBooleanResult(operationSign, name, containsType);
             }
             else {
                 semanticServices.getErrorHandler().structuralError(operationSign.getNode(), "Unknown operation");
             }
         }
 
+        private JetType assureBooleanResult(JetSimpleNameExpression operationSign, String name, JetType resultType) {
+            if (resultType != null) {
+                // TODO : Relax?
+                TypeConstructor booleanTypeConstructor = semanticServices.getStandardLibrary().getBoolean().getTypeConstructor();
+                if (!resultType.getConstructor().equals(booleanTypeConstructor)) {
+                    semanticServices.getErrorHandler().structuralError(operationSign.getNode(), "'" + name + "' must return Boolean but returns " + resultType);
+                    return null;
+                } else {
+                    return resultType;
+                }
+            }
+            return resultType;
+        }
+
         @Override
         public void visitArrayAccessExpression(JetArrayAccessExpression expression) {
             JetExpression arrayExpression = expression.getArrayExpression();
@@ -655,13 +672,17 @@ public class JetTypeInferrer {
         }
 
         private JetType getTypeForBinaryCall(JetBinaryExpression expression, @NotNull String name, JetScope scope, boolean reportUnresolved) {
-            JetSimpleNameExpression operationSign = expression.getOperationReference();
             JetExpression left = expression.getLeft();
-            JetType leftType = getType(scope, left, false);
             JetExpression right = expression.getRight();
             if (right == null) {
                 return ErrorType.createErrorType("No right argument"); // TODO
             }
+            JetSimpleNameExpression operationSign = expression.getOperationReference();
+            return getTypeForBinaryCall(scope, left, operationSign, right, name, reportUnresolved);
+        }
+
+        private JetType getTypeForBinaryCall(JetScope scope, JetExpression left, JetSimpleNameExpression operationSign, @NotNull JetExpression right, String name, boolean reportUnresolved) {
+            JetType leftType = getType(scope, left, false);
             JetType rightType = getType(scope, right, false);
             FunctionDescriptor functionDescriptor = lookupFunction(scope, operationSign, name, leftType, Collections.singletonList(rightType), reportUnresolved);
             if (functionDescriptor != null) {

idea/testData/resolve/ResolveOfInfixExpressions.jet

@@ -10,6 +10,7 @@ import util.*
   ~mod~fun mod(t : String) : Int {}
   ~rangeTo~fun rangeTo(t : String) : Int {}
   ~==~fun equals(a : Any?) : Boolean {}
+  ~contains~fun contains(a : Any?) : Boolean {}
 }
 
 ~t~fun <~t.T~T> t(~t.t~t : `t.T`T) : `t.T`T {
@@ -29,6 +30,8 @@ import util.*
   x `rangeTo`.. ""
   x `==`== ""
   x `==`!= 1
+  1 `contains`in x
+  1 `contains`!in x
 }
 
 ~Foo~class Foo {