Warn about invalid checksums of addresses.

8 files changed, 117 insertions, 2 deletions

diff --git a/Changelog.md b/Changelog.md
index 7dd607d8..a14e9ec8 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -5,6 +5,7 @@ Features:
  * Compiler interface: Report source location for "stack too deep" errors.
  * AST: Use deterministic node identifiers.
  * Type system: Introduce type identifier strings.
+ * Type checker: Warn about invalid checksum for addresses and deduce type from valid ones.
  * Metadata: Do not include platform in the version number.
  * Code generator: Extract array utils into low-level functions.
 
diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp
index adb3d54f..533c787b 100644
--- a/libsolidity/analysis/TypeChecker.cpp
+++ b/libsolidity/analysis/TypeChecker.cpp
@@ -1565,6 +1565,16 @@ void TypeChecker::endVisit(ElementaryTypeNameExpression const& _expr)
 
 void TypeChecker::endVisit(Literal const& _literal)
 {
+	if (_literal.looksLikeAddress())
+	{
+		if (_literal.passesAddressChecksum())
+		{
+			_literal.annotation().type = make_shared<IntegerType>(0, IntegerType::Modifier::Address);
+			return;
+		}
+		else
+			warning(_literal.location(), "This looks like an address but has an invalid checksum.");
+	}
 	_literal.annotation().type = Type::forLiteral(_literal);
 	if (!_literal.annotation().type)
 		fatalTypeError(_literal.location(), "Invalid literal value.");
diff --git a/libsolidity/ast/AST.cpp b/libsolidity/ast/AST.cpp
index 8a43c3f7..e2b50dd7 100644
--- a/libsolidity/ast/AST.cpp
+++ b/libsolidity/ast/AST.cpp
@@ -20,8 +20,6 @@
  * Solidity abstract syntax tree.
  */
 
-#include <algorithm>
-#include <functional>
 #include <libsolidity/interface/Utils.h>
 #include <libsolidity/ast/AST.h>
 #include <libsolidity/ast/ASTVisitor.h>
@@ -30,6 +28,11 @@
 
 #include <libdevcore/SHA3.h>
 
+#include <boost/algorithm/string.hpp>
+
+#include <algorithm>
+#include <functional>
+
 using namespace std;
 using namespace dev;
 using namespace dev::solidity;
@@ -522,3 +525,39 @@ IdentifierAnnotation& Identifier::annotation() const
 		m_annotation = new IdentifierAnnotation();
 	return static_cast<IdentifierAnnotation&>(*m_annotation);
 }
+
+bool Literal::looksLikeAddress() const
+{
+	if (subDenomination() != SubDenomination::None)
+		return false;
+
+	string lit = value();
+	return lit.substr(0, 2) == "0x" && abs(int(lit.length()) - 42) <= 1;
+}
+
+bool Literal::passesAddressChecksum() const
+{
+	string lit = value();
+	solAssert(lit.substr(0, 2) == "0x", "Expected hex prefix");
+	lit = lit.substr(2);
+
+	if (lit.length() != 40)
+		return false;
+
+	h256 hash = keccak256(boost::algorithm::to_lower_copy(lit, std::locale::classic()));
+	for (size_t i = 0; i < 40; ++i)
+	{
+		char addressCharacter = lit[i];
+		bool lowerCase;
+		if ('a' <= addressCharacter && addressCharacter <= 'f')
+			lowerCase = true;
+		else if ('A' <= addressCharacter && addressCharacter <= 'F')
+			lowerCase = false;
+		else
+			continue;
+		unsigned nibble = (unsigned(hash[i / 2]) >> (4 * (1 - (i % 2)))) & 0xf;
+		if ((nibble >= 8) == lowerCase)
+			return false;
+	}
+	return true;
+}
diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index 4c75f7ea..743fdaa1 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -1584,6 +1584,11 @@ public:
 
 	SubDenomination subDenomination() const { return m_subDenomination; }
 
+	/// @returns true if this looks like a checksummed address.
+	bool looksLikeAddress() const;
+	/// @returns true if it passes the address checksum test.
+	bool passesAddressChecksum() const;
+
 private:
 	Token::Value m_token;
 	ASTPointer<ASTString> m_value;
diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index cefd0603..971e1f18 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -405,6 +405,14 @@ string IntegerType::toString(bool) const
 	return prefix + dev::toString(m_bits);
 }
 
+u256 IntegerType::literalValue(Literal const* _literal) const
+{
+	solAssert(m_modifier == Modifier::Address, "");
+	solAssert(_literal, "");
+	solAssert(_literal->value().substr(0, 2) == "0x", "");
+	return u256(_literal->value());
+}
+
 TypePointer IntegerType::binaryOperatorResult(Token::Value _operator, TypePointer const& _other) const
 {
 	if (
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index 1e94631e..770cbb30 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -314,6 +314,8 @@ public:
 
 	virtual std::string toString(bool _short) const override;
 
+	virtual u256 literalValue(Literal const* _literal) const override;
+
 	virtual TypePointer encodingType() const override { return shared_from_this(); }
 	virtual TypePointer interfaceType(bool) const override { return shared_from_this(); }
 
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index fe0eeb1c..bda4e04d 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -1308,6 +1308,7 @@ void ExpressionCompiler::endVisit(Literal const& _literal)
 	{
 	case Type::Category::RationalNumber:
 	case Type::Category::Bool:
+	case Type::Category::Integer:
 		m_context << type->literalValue(&_literal);
 		break;
 	case Type::Category::StringLiteral:
diff --git a/test/libsolidity/SolidityNameAndTypeResolution.cpp b/test/libsolidity/SolidityNameAndTypeResolution.cpp
index ce241c78..b6067ea5 100644
--- a/test/libsolidity/SolidityNameAndTypeResolution.cpp
+++ b/test/libsolidity/SolidityNameAndTypeResolution.cpp
@@ -4983,6 +4983,55 @@ BOOST_AUTO_TEST_CASE(constructible_internal_constructor)
 	success(text);
 }
 
+BOOST_AUTO_TEST_CASE(address_checksum_type_deduction)
+{
+	char const* text = R"(
+		contract C {
+			function f() {
+				var x = 0xfA0bFc97E48458494Ccd857e1A85DC91F7F0046E;
+				x.send(2);
+			}
+		}
+	)";
+	success(text);
+}
+
+BOOST_AUTO_TEST_CASE(invalid_address_checksum)
+{
+	char const* text = R"(
+		contract C {
+			function f() {
+				var x = 0xFA0bFc97E48458494Ccd857e1A85DC91F7F0046E;
+			}
+		}
+	)";
+	CHECK_WARNING(text, "checksum");
+}
+
+BOOST_AUTO_TEST_CASE(invalid_address_no_checksum)
+{
+	char const* text = R"(
+		contract C {
+			function f() {
+				var x = 0xfa0bfc97e48458494ccd857e1a85dc91f7f0046e;
+			}
+		}
+	)";
+	CHECK_WARNING(text, "checksum");
+}
+
+BOOST_AUTO_TEST_CASE(invalid_address_length)
+{
+	char const* text = R"(
+		contract C {
+			function f() {
+				var x = 0xA0bFc97E48458494Ccd857e1A85DC91F7F0046E;
+			}
+		}
+	)";
+	CHECK_WARNING(text, "checksum");
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }