Improved "Stack too deep" error message.

Closes #2080.

libevmasm/CommonSubexpressionEliminator.cpp

@@ -428,7 +428,7 @@ void CSECodeGenerator::appendDup(int _fromPosition, SourceLocation const& _locat
 {
 	assertThrow(_fromPosition != c_invalidPosition, OptimizerException, "");
 	int instructionNum = 1 + m_stackHeight - _fromPosition;
-	assertThrow(instructionNum <= 16, StackTooDeepException, "Stack too deep.");
+	assertThrow(instructionNum <= 16, StackTooDeepException, "Stack too deep, try removing local variables.");
 	assertThrow(1 <= instructionNum, OptimizerException, "Invalid stack access.");
 	appendItem(AssemblyItem(dupInstruction(instructionNum), _location));
 	m_stack[m_stackHeight] = m_stack[_fromPosition];
@@ -441,7 +441,7 @@ void CSECodeGenerator::appendOrRemoveSwap(int _fromPosition, SourceLocation cons
 	if (_fromPosition == m_stackHeight)
 		return;
 	int instructionNum = m_stackHeight - _fromPosition;
-	assertThrow(instructionNum <= 16, StackTooDeepException, "Stack too deep.");
+	assertThrow(instructionNum <= 16, StackTooDeepException, "Stack too deep, try removing local variables.");
 	assertThrow(1 <= instructionNum, OptimizerException, "Invalid stack access.");
 	appendItem(AssemblyItem(swapInstruction(instructionNum), _location));
 

libsolidity/ArrayUtils.cpp

@@ -168,7 +168,10 @@ void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType cons
 		else
 			solAssert(false, "Copying of unknown type requested: " + sourceBaseType->toString());
 		// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end [target_byte_offset] [source_byte_offset] <source_value>...
-		solAssert(2 + byteOffsetSize + sourceBaseType->getSizeOnStack() <= 16, "Stack too deep.");
+		solAssert(
+			2 + byteOffsetSize + sourceBaseType->getSizeOnStack() <= 16,
+			"Stack too deep, try removing local variables."
+		);
 		// fetch target storage reference
 		m_context << eth::dupInstruction(2 + byteOffsetSize + sourceBaseType->getSizeOnStack());
 		if (haveByteOffsetTarget)

libsolidity/Compiler.cpp

@@ -367,7 +367,7 @@ bool Compiler::visit(FunctionDefinition const& _function)
 		stackLayout.push_back(i);
 	stackLayout += vector<int>(c_localVariablesSize, -1);
 
-	solAssert(stackLayout.size() <= 17, "Stack too deep.");
+	solAssert(stackLayout.size() <= 17, "Stack too deep, try removing local variables.");
 	while (stackLayout.back() != int(stackLayout.size() - 1))
 		if (stackLayout.back() < 0)
 		{

libsolidity/CompilerUtils.cpp

@@ -142,22 +142,25 @@ void CompilerUtils::moveToStackVariable(VariableDeclaration const& _variable)
 	solAssert(stackPosition >= size, "Variable size and position mismatch.");
 	// move variable starting from its top end in the stack
 	if (stackPosition - size + 1 > 16)
-		BOOST_THROW_EXCEPTION(CompilerError() << errinfo_sourceLocation(_variable.getLocation())
-											  << errinfo_comment("Stack too deep."));
+		BOOST_THROW_EXCEPTION(
+			CompilerError() <<
+			errinfo_sourceLocation(_variable.getLocation()) <<
+			errinfo_comment("Stack too deep, try removing local variables.")
+		);
 	for (unsigned i = 0; i < size; ++i)
 		m_context << eth::swapInstruction(stackPosition - size + 1) << eth::Instruction::POP;
 }
 
 void CompilerUtils::copyToStackTop(unsigned _stackDepth, unsigned _itemSize)
 {
-	solAssert(_stackDepth <= 16, "Stack too deep.");
+	solAssert(_stackDepth <= 16, "Stack too deep, try removing local variables.");
 	for (unsigned i = 0; i < _itemSize; ++i)
 		m_context << eth::dupInstruction(_stackDepth);
 }
 
 void CompilerUtils::moveToStackTop(unsigned _stackDepth)
 {
-	solAssert(_stackDepth <= 15, "Stack too deep.");
+	solAssert(_stackDepth <= 15, "Stack too deep, try removing local variables.");
 	for (unsigned i = 0; i < _stackDepth; ++i)
 		m_context << eth::swapInstruction(1 + i);
 }

libsolidity/ExpressionCompiler.cpp

@@ -263,7 +263,7 @@ bool ExpressionCompiler::visit(Assignment const& _assignment)
 		appendOrdinaryBinaryOperatorCode(Token::AssignmentToBinaryOp(op), *_assignment.getType());
 		if (lvalueSize > 0)
 		{
-			solAssert(itemSize + lvalueSize <= 16, "Stack too deep.");
+			solAssert(itemSize + lvalueSize <= 16, "Stack too deep, try removing local variables.");
 			// value [lvalue_ref] updated_value
 			for (unsigned i = 0; i < itemSize; ++i)
 				m_context << eth::swapInstruction(itemSize + lvalueSize) << eth::Instruction::POP;

libsolidity/LValue.cpp

@@ -42,8 +42,11 @@ void StackVariable::retrieveValue(SourceLocation const& _location, bool) const
 {
 	unsigned stackPos = m_context.baseToCurrentStackOffset(m_baseStackOffset);
 	if (stackPos >= 15) //@todo correct this by fetching earlier or moving to memory
-		BOOST_THROW_EXCEPTION(CompilerError()
-			<< errinfo_sourceLocation(_location) << errinfo_comment("Stack too deep."));
+		BOOST_THROW_EXCEPTION(
+			CompilerError() <<
+			errinfo_sourceLocation(_location) <<
+			errinfo_comment("Stack too deep, try removing local variables.")
+		);
 	for (unsigned i = 0; i < m_size; ++i)
 		m_context << eth::dupInstruction(stackPos + 1);
 }
@@ -52,8 +55,11 @@ void StackVariable::storeValue(Type const&, SourceLocation const& _location, boo
 {
 	unsigned stackDiff = m_context.baseToCurrentStackOffset(m_baseStackOffset) - m_size + 1;
 	if (stackDiff > 16)
-		BOOST_THROW_EXCEPTION(CompilerError()
-			<< errinfo_sourceLocation(_location) << errinfo_comment("Stack too deep."));
+		BOOST_THROW_EXCEPTION(
+			CompilerError() <<
+			errinfo_sourceLocation(_location) <<
+			errinfo_comment("Stack too deep, try removing local variables.")
+		);
 	else if (stackDiff > 0)
 		for (unsigned i = 0; i < m_size; ++i)
 			m_context << eth::swapInstruction(stackDiff) << eth::Instruction::POP;
@@ -65,8 +71,11 @@ void StackVariable::setToZero(SourceLocation const& _location, bool) const
 {
 	unsigned stackDiff = m_context.baseToCurrentStackOffset(m_baseStackOffset);
 	if (stackDiff > 16)
-		BOOST_THROW_EXCEPTION(CompilerError()
-			<< errinfo_sourceLocation(_location) << errinfo_comment("Stack too deep."));
+		BOOST_THROW_EXCEPTION(
+			CompilerError() <<
+			errinfo_sourceLocation(_location) <<
+			errinfo_comment("Stack too deep, try removing local variables.")
+		);
 	solAssert(stackDiff >= m_size - 1, "");
 	for (unsigned i = 0; i < m_size; ++i)
 		m_context << u256(0) << eth::swapInstruction(stackDiff + 1 - i)
@@ -204,7 +213,10 @@ void StorageItem::storeValue(Type const& _sourceType, SourceLocation const& _loc
 				// stack: source_ref source_off target_ref target_off member_slot_offset member_byte_offset source_member_ref source_member_off
 				StorageItem(m_context, *memberType).retrieveValue(_location, true);
 				// stack: source_ref source_off target_ref target_off member_offset source_value...
-				solAssert(4 + memberType->getSizeOnStack() <= 16, "Stack too deep.");
+				solAssert(
+					4 + memberType->getSizeOnStack() <= 16,
+					"Stack too deep, try removing local varibales."
+				);
 				m_context
 					<< eth::dupInstruction(4 + memberType->getSizeOnStack())
 					<< eth::dupInstruction(3 + memberType->getSizeOnStack()) << eth::Instruction::ADD