From 0819e31de88fa9f99dcffc70fd6cd6de8ee8ae4b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kamil=20=C5=9Aliwak?= <kamil.sliwak@codepoets.it>
Date: Mon, 18 Sep 2023 14:01:32 +0200
Subject: [PATCH] Reject duplicate built-in type definitions

---
 .../analysis/TypeRegistration.cpp             | 20 ++++++++++++++++++-
 .../experimental/analysis/TypeRegistration.h  |  1 +
 .../builtin_type_definition_duplicate.sol     | 17 ++++++++++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)
 create mode 100644 test/libsolidity/syntaxTests/experimental/builtin/builtin_type_definition_duplicate.sol

diff --git a/libsolidity/experimental/analysis/TypeRegistration.cpp b/libsolidity/experimental/analysis/TypeRegistration.cpp
index 78f3a8131..43fd8d117 100644
--- a/libsolidity/experimental/analysis/TypeRegistration.cpp
+++ b/libsolidity/experimental/analysis/TypeRegistration.cpp
@@ -172,7 +172,25 @@ void TypeRegistration::endVisit(TypeDefinition const& _typeDefinition)
 		return;
 
 	if (auto const* builtin = dynamic_cast<Builtin const*>(_typeDefinition.typeExpression()))
-		annotation(_typeDefinition).typeConstructor = annotation(*builtin).typeConstructor;
+	{
+		auto [previousDefinitionIt, inserted] = annotation().builtinTypeDefinitions.try_emplace(
+			builtin->nameParameter(),
+			&_typeDefinition
+		);
+
+		if (inserted)
+			annotation(_typeDefinition).typeConstructor = annotation(*builtin).typeConstructor;
+		else
+		{
+			auto const& [builtinName, previousDefinition] = *previousDefinitionIt;
+			m_errorReporter.typeError(
+				9609_error,
+				_typeDefinition.location(),
+				SecondarySourceLocation{}.append("Previous definition:", previousDefinition->location()),
+				"Duplicate builtin type definition."
+			);
+		}
+	}
 	else
 		annotation(_typeDefinition).typeConstructor = m_typeSystem.declareTypeConstructor(
 			_typeDefinition.name(),
diff --git a/libsolidity/experimental/analysis/TypeRegistration.h b/libsolidity/experimental/analysis/TypeRegistration.h
index e8b087daa..9bc49a29c 100644
--- a/libsolidity/experimental/analysis/TypeRegistration.h
+++ b/libsolidity/experimental/analysis/TypeRegistration.h
@@ -42,6 +42,7 @@ public:
 	{
 		std::map<PrimitiveClass, TypeClassInstantiations> primitiveClassInstantiations;
 		std::map<BuiltinClass, TypeClassInstantiations> builtinClassInstantiations;
+		std::map<std::string, TypeDefinition const*> builtinTypeDefinitions;
 	};
 	TypeRegistration(Analysis& _analysis);
 
diff --git a/test/libsolidity/syntaxTests/experimental/builtin/builtin_type_definition_duplicate.sol b/test/libsolidity/syntaxTests/experimental/builtin/builtin_type_definition_duplicate.sol
new file mode 100644
index 000000000..28f6c39fd
--- /dev/null
+++ b/test/libsolidity/syntaxTests/experimental/builtin/builtin_type_definition_duplicate.sol
@@ -0,0 +1,17 @@
+pragma experimental solidity;
+
+type void1 = __builtin("void");
+type void2 = __builtin("void");
+
+type word1 = __builtin("word");
+type word2 = __builtin("word");
+
+type fun1(T, U) = __builtin("fun");
+type fun2(T, U) = __builtin("fun");
+// ====
+// EVMVersion: >=constantinople
+// ----
+// Warning 2264: (0-29): Experimental features are turned on. Do not use experimental features on live deployments.
+// TypeError 9609: (63-94): Duplicate builtin type definition.
+// TypeError 9609: (128-159): Duplicate builtin type definition.
+// TypeError 9609: (197-232): Duplicate builtin type definition.