Merge pull request #7709 from ethereum/overloadMsgForMagic

Reconstruct function definition for magic variables in overload error message.

test/cmdlineTests/require_overload/err

@@ -0,0 +1,5 @@
+require_overload/input.sol:4:9: Error: No matching declaration found after argument-dependent lookup.
+        require(this);
+        ^-----^
+Candidate: function require(bool)
+Candidate: function require(bool, string memory)

test/cmdlineTests/require_overload/exit

@@ -0,0 +1 @@
+1

test/cmdlineTests/require_overload/input.sol

@@ -0,0 +1,6 @@
+pragma solidity >=0.0;
+contract C {
+    function f() public pure {
+        require(this);
+    }
+}