Reconstruct function definition for magic variables in overload error message.

libsolidity/analysis/TypeChecker.cpp

@@ -2359,7 +2359,18 @@ bool TypeChecker::visit(Identifier const& _identifier)
 				SecondarySourceLocation ssl;
 
 				for (Declaration const* declaration: annotation.overloadedDeclarations)
-					ssl.append("Candidate:", declaration->location());
+					if (declaration->location().isEmpty())
+					{
+						// Try to re-construct function definition
+						string description;
+						for (auto const& param: declaration->functionType(true)->parameterTypes())
+							description += (description.empty() ? "" : ", ") + param->toString(false);
+						description = "function " + _identifier.name() + "(" + description + ")";
+
+						ssl.append("Candidate: " + description, declaration->location());
+					}
+					else
+						ssl.append("Candidate:", declaration->location());
 				if (candidates.empty())
 					m_errorReporter.fatalTypeError(_identifier.location(), ssl, "No matching declaration found after argument-dependent lookup.");
 				else

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);
+    }
+}