Merge pull request #4054 from ethereum/token-names

Improve parser error messages

libsolidity/inlineasm/AsmParser.cpp

@@ -276,7 +276,7 @@ assembly::Expression Parser::parseExpression()
 		int args = instructionInfo(instr.instruction).args;
 		if (args > 0 && currentToken() != Token::LParen)
 			fatalParserError(string(
-				"Expected token \"(\" (\"" +
+				"Expected '(' (instruction \"" +
 				instructionNames().at(instr.instruction) +
 				"\" expects " +
 				boost::lexical_cast<string>(args) +
@@ -504,7 +504,7 @@ assembly::Expression Parser::parseCall(Parser::ElementaryOperation&& _initialOp)
 			/// check for premature closing parentheses
 			if (currentToken() == Token::RParen)
 				fatalParserError(string(
-					"Expected expression (\"" +
+					"Expected expression (instruction \"" +
 					instructionNames().at(instr) +
 					"\" expects " +
 					boost::lexical_cast<string>(args) +
@@ -516,7 +516,7 @@ assembly::Expression Parser::parseCall(Parser::ElementaryOperation&& _initialOp)
 			{
 				if (currentToken() != Token::Comma)
 					fatalParserError(string(
-						"Expected comma (\"" +
+						"Expected ',' (instruction \"" +
 						instructionNames().at(instr) +
 						"\" expects " +
 						boost::lexical_cast<string>(args) +
@@ -529,7 +529,7 @@ assembly::Expression Parser::parseCall(Parser::ElementaryOperation&& _initialOp)
 		ret.location.end = endPosition();
 		if (currentToken() == Token::Comma)
 			fatalParserError(string(
-				"Expected ')' (\"" +
+				"Expected ')' (instruction \"" +
 				instructionNames().at(instr) +
 				"\" expects " +
 				boost::lexical_cast<string>(args) +

libsolidity/parsing/Parser.cpp

@@ -528,7 +528,7 @@ ASTPointer<EnumDefinition> Parser::parseEnumDefinition()
 			break;
 		expectToken(Token::Comma);
 		if (m_scanner->currentToken() != Token::Identifier)
-			fatalParserError(string("Expected Identifier after ','"));
+			fatalParserError(string("Expected identifier after ','"));
 	}
 	if (members.size() == 0)
 		parserError({"enum with no members is not allowed."});

libsolidity/parsing/ParserBase.cpp

@@ -68,35 +68,24 @@ void ParserBase::expectToken(Token::Value _value, bool _advance)
 	Token::Value tok = m_scanner->currentToken();
 	if (tok != _value)
 	{
-		if (Token::isReservedKeyword(tok))
+		auto tokenName = [this](Token::Value _token)
 		{
-			fatalParserError(
-				string("Expected token ") +
-				string(Token::name(_value)) +
-				string(" got reserved keyword '") +
-				string(Token::name(tok)) +
-				string("'")
-			);
-		}
-		else if (Token::isElementaryTypeName(tok)) //for the sake of accuracy in reporting
-		{
-			ElementaryTypeNameToken elemTypeName = m_scanner->currentElementaryTypeNameToken();
-			fatalParserError(
-				string("Expected token ") +
-				string(Token::name(_value)) +
-				string(" got '") +
-				elemTypeName.toString() +
-				string("'")
-			);
-		}
-		else
-			fatalParserError(
-				string("Expected token ") +
-				string(Token::name(_value)) +
-				string(" got '") +
-				string(Token::name(m_scanner->currentToken())) +
-				string("'")
-			);
+			if (_token == Token::Identifier)
+				return string("identifier");
+			else if (_token == Token::EOS)
+				return string("end of source");
+			else if (Token::isReservedKeyword(_token))
+				return string("reserved keyword '") + Token::friendlyName(_token) + "'";
+			else if (Token::isElementaryTypeName(_token)) //for the sake of accuracy in reporting
+			{
+				ElementaryTypeNameToken elemTypeName = m_scanner->currentElementaryTypeNameToken();
+				return string("'") + elemTypeName.toString() + "'";
+			}
+			else
+				return string("'") + Token::friendlyName(_token) + "'";
+		};
+
+		fatalParserError(string("Expected ") + tokenName(_value) + string(" but got ") + tokenName(tok));
 	}
 	if (_advance)
 		m_scanner->next();

libsolidity/parsing/Token.h

@@ -304,6 +304,17 @@ public:
 		return m_string[tok];
 	}
 
+	static std::string friendlyName(Value tok)
+	{
+		char const* ret = toString(tok);
+		if (ret == nullptr)
+		{
+			ret = name(tok);
+			solAssert(ret != nullptr, "");
+		}
+		return std::string(ret);
+	}
+
 	// @returns the precedence > 0 for binary and compare
 	// operators; returns 0 otherwise.
 	static int precedence(Value tok)