Unary + and - for numbers

idea/src/jet/lang/Library.jet

@@ -104,6 +104,8 @@ class Double : Number, Comparable<Double>  {
 
   fun inc() : Double
   fun dec() : Double
+  fun plus() : Double
+  fun minus() : Double
 }
 
 class Float : Number, Comparable<Float>  {
@@ -165,6 +167,8 @@ class Float : Number, Comparable<Float>  {
 
   fun inc() : Float
   fun dec() : Float
+  fun plus() : Float
+  fun minus() : Float
 }
 
 class Long : Number, Comparable<Long> {
@@ -226,6 +230,8 @@ class Long : Number, Comparable<Long> {
 
   fun inc() : Long
   fun dec() : Long
+  fun plus() : Long
+  fun minus() : Long
 }
 
 class Int : Number, Comparable<Int> {
@@ -287,6 +293,8 @@ class Int : Number, Comparable<Int> {
 
   fun inc() : Int
   fun dec() : Int
+  fun plus() : Int
+  fun minus() : Int
 }
 
 class Char : Number, Comparable<Char> {
@@ -348,6 +356,8 @@ class Char : Number, Comparable<Char> {
 
   fun inc() : Char
   fun dec() : Char
+  fun plus() : Int
+  fun minus() : Int
 }
 
 class Short : Number, Comparable<Char> {
@@ -409,6 +419,8 @@ class Short : Number, Comparable<Char> {
 
   fun inc() : Short
   fun dec() : Short
+  fun plus() : Int
+  fun minus() : Int
 }
 
 class Byte : Number, Comparable<Char> {
@@ -470,4 +482,6 @@ class Byte : Number, Comparable<Char> {
 
   fun inc() : Byte
   fun dec() : Byte
+  fun plus() : Int
+  fun minus() : Int
 }
\ No newline at end of file

idea/src/org/jetbrains/jet/lang/parsing/JetExpressionParsing.java

@@ -1358,7 +1358,7 @@ public class JetExpressionParsing extends AbstractJetParsing {
     }
 
     /*
-     * "new" constructorInvocation // identical to new nunctionCall
+     * "new" constructorInvocation // identical to new functionCall
      *
      * constructorInvocation
      *   : userType valueArguments

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

@@ -653,16 +653,26 @@ public class JetTypeInferrer {
         @Override
         public void visitUnaryExpression(JetUnaryExpression expression) {
             JetSimpleNameExpression operationSign = expression.getOperationSign();
-            String name = unaryOperationNames.get(operationSign.getReferencedNameElementType());
+            IElementType operationType = operationSign.getReferencedNameElementType();
+            String name = unaryOperationNames.get(operationType);
             if (name == null) {
                 semanticServices.getErrorHandler().genericError(operationSign.getNode(), "Unknown unary operation");
             }
             else {
-                JetType type = getType(scope, expression.getBaseExpression(), false);
-                if (type != null) {
-                    FunctionDescriptor functionDescriptor = lookupFunction(scope, expression.getOperationSign(), name, type, Collections.<JetType>emptyList(), true);
+                JetType receiverType = getType(scope, expression.getBaseExpression(), false);
+                if (receiverType != null) {
+                    FunctionDescriptor functionDescriptor = lookupFunction(scope, expression.getOperationSign(), name, receiverType, Collections.<JetType>emptyList(), true);
                     if (functionDescriptor != null) {
-                        result = functionDescriptor.getUnsubstitutedReturnType();
+                        JetType returnType = functionDescriptor.getUnsubstitutedReturnType();
+                        if (operationType == JetTokens.PLUSPLUS || operationType == JetTokens.MINUSMINUS) {
+                            if (!semanticServices.getTypeChecker().isSubtypeOf(returnType, receiverType)) {
+                                 semanticServices.getErrorHandler().genericError(operationSign.getNode(), name + " must return " + receiverType + " but returns " + returnType);
+                            }
+                            // TODO : Maybe returnType?
+                            result = receiverType;
+                        } else {
+                            result = returnType;
+                        }
                     }
                 }
             }

idea/testData/resolve/ResolveOfInfixExpressions.jet

@@ -44,8 +44,10 @@ import util.*
 
 ~Bar~class Bar : Foo {
   ~not~fun not() : String {}
-  ~inc~fun inc() : Unit
-  ~dec~fun dec() : Unit
+  ~inc~fun inc() : Bar
+  ~dec~fun dec() : Bar
+  ~-~fun minus() : Bar
+  ~+~fun plus() : Bar
 }
 
 fun <T> tt(t : T) : T {
@@ -68,6 +70,8 @@ fun <T> tt(t : T) : T {
   `dec`--y
   y`dec`--
   y `+=`+= 1
+  `+`+y
+  `-`-y
   1 `std::Int.compareTo(Double)`> 2.0
   1 `std::Int.compareTo(Double)`< 2.0
   1 `std::Int.compareTo(Double)`>= 2.0