Move hash collisions checks.

1 files changed, 16 insertions, 0 deletions

diff --git a/libsolidity/analysis/ContractLevelChecker.cpp b/libsolidity/analysis/ContractLevelChecker.cpp
index e2208f3f..419ebe93 100644
--- a/libsolidity/analysis/ContractLevelChecker.cpp
+++ b/libsolidity/analysis/ContractLevelChecker.cpp
@@ -43,6 +43,7 @@ bool ContractLevelChecker::check(ContractDefinition const& _contract)
 	checkConstructor(_contract);
 	checkFallbackFunction(_contract);
 	checkExternalTypeClashes(_contract);
+	checkHashCollisions(_contract);
 
 	return Error::containsOnlyWarnings(m_errorReporter.errors());
 }
@@ -420,3 +421,18 @@ void ContractLevelChecker::checkExternalTypeClashes(ContractDefinition const& _c
 						"Function overload clash during conversion to external types for arguments."
 					);
 }
+
+void ContractLevelChecker::checkHashCollisions(ContractDefinition const& _contract)
+{
+	set<FixedHash<4>> hashes;
+	for (auto const& it: _contract.interfaceFunctionList())
+	{
+		FixedHash<4> const& hash = it.first;
+		if (hashes.count(hash))
+			m_errorReporter.typeError(
+				_contract.location(),
+				string("Function signature hash collision for ") + it.second->externalSignature()
+			);
+		hashes.insert(hash);
+	}
+}