2 files changed, 20 insertions, 1 deletions
diff --git a/libsolidity/inlineasm/AsmAnalysis.cpp b/libsolidity/inlineasm/AsmAnalysis.cpp
index 13852880..36ac0e75 100644
--- a/libsolidity/inlineasm/AsmAnalysis.cpp
+++ b/libsolidity/inlineasm/AsmAnalysis.cpp
@@ -65,6 +65,7 @@ bool AsmAnalyzer::operator()(assembly::Instruction const& _instruction)
 	auto const& info = instructionInfo(_instruction.instruction);
 	m_stackHeight += info.ret - info.args;
 	m_info.stackHeightInfo[&_instruction] = m_stackHeight;
+	warnOnFutureInstruction(_instruction.instruction, _instruction.location);
 	return true;
 }
 
@@ -149,6 +150,7 @@ bool AsmAnalyzer::operator()(FunctionalInstruction const& _instr)
 	if (!(*this)(_instr.instruction))
 		success = false;
 	m_info.stackHeightInfo[&_instr] = m_stackHeight;
+	warnOnFutureInstruction(_instr.instruction.instruction, _instr.location);
 	return success;
 }
 
@@ -431,7 +433,6 @@ Scope& AsmAnalyzer::scope(Block const* _block)
 	solAssert(scopePtr, "Scope requested but not present.");
 	return *scopePtr;
 }
-
 void AsmAnalyzer::expectValidType(string const& type, SourceLocation const& _location)
 {
 	if (!m_julia)
@@ -443,3 +444,20 @@ void AsmAnalyzer::expectValidType(string const& type, SourceLocation const& _loc
 			"\"" + type + "\" is not a valid type (user defined types are not yet supported)."
 		);
 }
+
+void AsmAnalyzer::warnOnFutureInstruction(solidity::Instruction _instr, SourceLocation const& _location)
+{
+	switch (_instr)
+	{
+	case solidity::Instruction::RETURNDATASIZE:
+	case solidity::Instruction::RETURNDATACOPY:
+		m_errorReporter.warning(
+			_location,
+			"The RETURNDATASIZE/RETURNDATACOPY instructions are only available after "
+			"the Metropolis hard fork. Before that they act as an invalid instruction."
+		);
+		break;
+	default:
+		break;
+	}
+}
diff --git a/libsolidity/inlineasm/AsmAnalysis.h b/libsolidity/inlineasm/AsmAnalysis.h
index e7748bcf..55b409ba 100644
--- a/libsolidity/inlineasm/AsmAnalysis.h
+++ b/libsolidity/inlineasm/AsmAnalysis.h
@@ -97,6 +97,7 @@ private:
 
 	Scope& scope(assembly::Block const* _block);
 	void expectValidType(std::string const& type, SourceLocation const& _location);
+	void warnOnFutureInstruction(solidity::Instruction _instr, SourceLocation const& _location);
 
 	int m_stackHeight = 0;
 	julia::ExternalIdentifierAccess::Resolver m_resolver;