Merge pull request #2529 from ethereum/warnThrow

Deprecate throw.

Author: axic

Changelog.md

@@ -1,11 +1,12 @@
 ### 0.4.13 (unreleased)
 
 Features:
+ * Syntax Checker: Deprecated "throw" in favour of require(), assert() and revert().
  * Type Checker: Warn if a local storage reference variable does not explicitly use the keyword ``storage``.
 
 Bugfixes:
- * Compiler Interface: Only output AST if analysis was successful.
  * Code Generator: Correctly unregister modifier variables.
+ * Compiler Interface: Only output AST if analysis was successful.
  * Error Output: Do not omit the error type.
 
 ### 0.4.12 (2017-07-03)

libsolidity/analysis/SyntaxChecker.cpp

@@ -135,6 +135,16 @@ bool SyntaxChecker::visit(Break const& _breakStatement)
 	return true;
 }
 
+bool SyntaxChecker::visit(Throw const& _throwStatement)
+{
+	m_errorReporter.warning(
+		_throwStatement.location(),
+		"\"throw\" is deprecated in favour of \"revert()\", \"require()\" and \"assert()\"."
+	);
+
+	return true;
+}
+
 bool SyntaxChecker::visit(UnaryOperation const& _operation)
 {
 	if (_operation.getOperator() == Token::Add)

libsolidity/analysis/SyntaxChecker.h

@@ -33,6 +33,7 @@ namespace solidity
  *  - whether continue/break is in a for/while loop.
  *  - whether a modifier contains at least one '_'
  *  - issues deprecation warnings for unary '+'
+ *  - issues deprecation warning for throw
  */
 class SyntaxChecker: private ASTConstVisitor
 {
@@ -59,6 +60,8 @@ class SyntaxChecker: private ASTConstVisitor
 	virtual bool visit(Continue const& _continueStatement) override;
 	virtual bool visit(Break const& _breakStatement) override;
 
+	virtual bool visit(Throw const& _throwStatement) override;
+
 	virtual bool visit(UnaryOperation const& _operation) override;
 
 	virtual bool visit(PlaceholderStatement const& _placeholderStatement) override;

test/libsolidity/SolidityNameAndTypeResolution.cpp

@@ -5860,6 +5860,18 @@ BOOST_AUTO_TEST_CASE(using_interface_complex)
 	success(text);
 }
 
+BOOST_AUTO_TEST_CASE(warn_about_throw)
+{
+	char const* text = R"(
+		contract C {
+			function f() {
+				throw;
+			}
+		}
+	)";
+	CHECK_WARNING(text, "\"throw\" is deprecated");
+}
+
 BOOST_AUTO_TEST_CASE(bare_revert)
 {
 	char const* text = R"(