Add receive function to Proxy

contracts/proxy/IProxy.sol

@@ -6,4 +6,6 @@ import { _IProxy } from './_IProxy.sol';
 
 interface IProxy is _IProxy {
     fallback() external payable;
+
+    receive() external payable;
 }

contracts/proxy/Proxy.sol

@@ -16,4 +16,8 @@ abstract contract Proxy is IProxy, _Proxy {
     fallback() external payable {
         _fallback();
     }
+
+    receive() external payable {
+        _receive();
+    }
 }

contracts/proxy/_Proxy.sol

@@ -68,4 +68,11 @@ abstract contract _Proxy is _IProxy {
 
         revert Proxy__ImplementationIsNotContract();
     }
+
+    /**
+     * @notice received ether is forwarded to the fallback function
+     */
+    function _receive() internal virtual {
+        _fallback();
+    }
 }

contracts/proxy/diamond/ISolidstateDiamondProxy.sol

@@ -16,6 +16,4 @@ interface ISolidstateDiamondProxy is
     IDiamondProxyReadable,
     IDiamondProxyWritable,
     ISafeOwnable
-{
-    receive() external payable;
-}
+{}

contracts/proxy/diamond/SolidstateDiamondProxy.sol

@@ -99,8 +99,6 @@ abstract contract SolidstateDiamondProxy is
         _setOwner(msg.sender);
     }
 
-    receive() external payable {}
-
     function _transferOwnership(
         address account
     )

spec/proxy/Proxy.behavior.ts

@@ -37,5 +37,9 @@ export function describeBehaviorOfProxy(
         ).not.to.be.reverted;
       });
     });
+
+    describe('receive()', () => {
+      it('forwards value to implementation');
+    });
   });
 }

spec/proxy/diamond/DiamondProxy.behavior.ts

@@ -55,5 +55,9 @@ export function describeBehaviorOfDiamondProxy(
         });
       });
     });
+
+    describe('receive()', () => {
+      it('todo');
+    });
   });
 }

spec/proxy/diamond/fallback/DiamondProxyFallback.behavior.ts

@@ -37,6 +37,10 @@ export function describeBehaviorOfDiamondProxyFallback(
       it('forwards data without matching selector to fallback contract');
     });
 
+    describe('receive()', () => {
+      it('forwards value to fallback contract');
+    });
+
     describe('#getFallbackAddress()', () => {
       it('returns the fallback address', async () => {
         expect(await instance.getFallbackAddress.staticCall()).to.equal(