Turn throw into a syntax error for 0.5.0

Changelog.md

@@ -6,6 +6,7 @@ Features:
  * Type Checker: Disallow uninitialized storage pointers as experimental 0.5.0 feature.
  * Support and recommend using ``emit EventName();`` to call events explicitly.
  * Syntax Analyser: Do not warn about experimental features if they do not concern code generation.
+ * Syntax Checker: Mark ``throw`` as an error as experimental 0.5.0 feature.
 
 Bugfixes:
  * Assembly: Raise error on oversized number literals in assembly.

libsolidity/analysis/SyntaxChecker.cpp

@@ -174,10 +174,18 @@ bool SyntaxChecker::visit(Break const& _breakStatement)
 
 bool SyntaxChecker::visit(Throw const& _throwStatement)
 {
-	m_errorReporter.warning(
-		_throwStatement.location(),
-		"\"throw\" is deprecated in favour of \"revert()\", \"require()\" and \"assert()\"."
-	);
+	bool const v050 = m_sourceUnit->annotation().experimentalFeatures.count(ExperimentalFeature::V050);
+
+	if (v050)
+		m_errorReporter.syntaxError(
+			_throwStatement.location(),
+			"\"throw\" is deprecated in favour of \"revert()\", \"require()\" and \"assert()\"."
+		);
+	else
+		m_errorReporter.warning(
+			_throwStatement.location(),
+			"\"throw\" is deprecated in favour of \"revert()\", \"require()\" and \"assert()\"."
+		);
 
 	return true;
 }

test/libsolidity/SolidityNameAndTypeResolution.cpp

@@ -6332,7 +6332,16 @@ BOOST_AUTO_TEST_CASE(warn_about_throw)
 			}
 		}
 	)";
-	CHECK_WARNING(text, "\"throw\" is deprecated");
+	CHECK_WARNING(text, "\"throw\" is deprecated in favour of \"revert()\", \"require()\" and \"assert()\"");
+	text = R"(
+                pragma experimental "v0.5.0";
+		contract C {
+			function f() pure public {
+				throw;
+			}
+		}
+	)";
+	CHECK_ERROR(text, SyntaxError, "\"throw\" is deprecated in favour of \"revert()\", \"require()\" and \"assert()\"");
 }
 
 BOOST_AUTO_TEST_CASE(bare_revert)