Merge pull request #4054 from ethereum/token-names

Improve parser error messages

Changelog.md

@@ -5,6 +5,7 @@ Features:
  * Code Generator: Use native shift instructions on target Constantinople.
  * Gas Estimator: Only explore paths with higher gas costs. This reduces accuracy but greatly improves the speed of gas estimation.
  * Optimizer: Remove unnecessary masking of the result of known short instructions (``ADDRESS``, ``CALLER``, ``ORIGIN`` and ``COINBASE``).
+ * Parser: Display nicer error messages by showing the actual tokens and not internal names.
  * Type Checker: Deprecate the ``years`` unit denomination and raise a warning for it (or an error as experimental 0.5.0 feature).
  * Type Checker: Make literals (without explicit type casting) an error for tight packing as experimental 0.5.0 feature.
  * Type Checker: Warn about wildcard tuple assignments (this will turn into an error with version 0.5.0).

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)

test/libjulia/Parser.cpp

@@ -212,10 +212,10 @@ BOOST_AUTO_TEST_CASE(tokens_as_identifers)
 
 BOOST_AUTO_TEST_CASE(lacking_types)
 {
-	CHECK_ERROR("{ let x := 1:u256 }", ParserError, "Expected token Identifier got 'Assign'");
-	CHECK_ERROR("{ let x:u256 := 1 }", ParserError, "Expected token Colon got 'RBrace'");
-	CHECK_ERROR("{ function f(a) {} }", ParserError, "Expected token Colon got 'RParen'");
-	CHECK_ERROR("{ function f(a:u256) -> b {} }", ParserError, "Expected token Colon got 'LBrace'");
+	CHECK_ERROR("{ let x := 1:u256 }", ParserError, "Expected identifier but got '='");
+	CHECK_ERROR("{ let x:u256 := 1 }", ParserError, "Expected ':' but got '}'");
+	CHECK_ERROR("{ function f(a) {} }", ParserError, "Expected ':' but got ')'");
+	CHECK_ERROR("{ function f(a:u256) -> b {} }", ParserError, "Expected ':' but got '{'");
 }
 
 BOOST_AUTO_TEST_CASE(invalid_types)
@@ -294,7 +294,7 @@ BOOST_AUTO_TEST_CASE(if_statement)
 BOOST_AUTO_TEST_CASE(if_statement_invalid)
 {
 	CHECK_ERROR("{ if let x:u256 {} }", ParserError, "Literal or identifier expected.");
-	CHECK_ERROR("{ if true:bool let x:u256 := 3:u256 }", ParserError, "Expected token LBrace");
+	CHECK_ERROR("{ if true:bool let x:u256 := 3:u256 }", ParserError, "Expected '{' but got reserved keyword 'let'");
 	// TODO change this to an error once we check types.
 	BOOST_CHECK(successParse("{ if 42:u256 { } }"));
 }

test/libsolidity/InlineAssembly.cpp

@@ -170,7 +170,7 @@ BOOST_AUTO_TEST_CASE(smoke_test)
 
 BOOST_AUTO_TEST_CASE(surplus_input)
 {
-	CHECK_PARSE_ERROR("{ } { }", ParserError, "Expected token EOS");
+	CHECK_PARSE_ERROR("{ } { }", ParserError, "Expected end of source but got '{'");
 }
 
 BOOST_AUTO_TEST_CASE(simple_instructions)
@@ -246,7 +246,7 @@ BOOST_AUTO_TEST_CASE(functional)
 
 BOOST_AUTO_TEST_CASE(functional_partial)
 {
-	CHECK_PARSE_ERROR("{ let x := byte }", ParserError, "Expected token \"(\"");
+	CHECK_PARSE_ERROR("{ let x := byte }", ParserError, "Expected '(' (instruction \"byte\" expects 2 arguments)");
 }
 
 BOOST_AUTO_TEST_CASE(functional_partial_success)
@@ -290,10 +290,10 @@ BOOST_AUTO_TEST_CASE(if_statement_scope)
 
 BOOST_AUTO_TEST_CASE(if_statement_invalid)
 {
-	CHECK_PARSE_ERROR("{ if mload {} }", ParserError, "Expected token \"(\"");
+	CHECK_PARSE_ERROR("{ if mload {} }", ParserError, "Expected '(' (instruction \"mload\" expects 1 arguments)");
 	BOOST_CHECK("{ if calldatasize() {}");
 	CHECK_PARSE_ERROR("{ if mstore(1, 1) {} }", ParserError, "Instruction \"mstore\" not allowed in this context");
-	CHECK_PARSE_ERROR("{ if 32 let x := 3 }", ParserError, "Expected token LBrace");
+	CHECK_PARSE_ERROR("{ if 32 let x := 3 }", ParserError, "Expected '{' but got reserved keyword 'let'");
 }
 
 BOOST_AUTO_TEST_CASE(switch_statement)
@@ -320,7 +320,7 @@ BOOST_AUTO_TEST_CASE(switch_duplicate_case)
 BOOST_AUTO_TEST_CASE(switch_invalid_expression)
 {
 	CHECK_PARSE_ERROR("{ switch {} default {} }", ParserError, "Literal, identifier or instruction expected.");
-	CHECK_PARSE_ERROR("{ switch mload default {} }", ParserError, "Expected token \"(\"");
+	CHECK_PARSE_ERROR("{ switch mload default {} }", ParserError, "Expected '(' (instruction \"mload\" expects 1 arguments)");
 	CHECK_PARSE_ERROR("{ switch mstore(1, 1) default {} }", ParserError, "Instruction \"mstore\" not allowed in this context");
 }
 
@@ -341,7 +341,7 @@ BOOST_AUTO_TEST_CASE(switch_invalid_case)
 
 BOOST_AUTO_TEST_CASE(switch_invalid_body)
 {
-	CHECK_PARSE_ERROR("{ switch 42 case 1 mul case 2 {} default {} }", ParserError, "Expected token LBrace got 'Identifier'");
+	CHECK_PARSE_ERROR("{ switch 42 case 1 mul case 2 {} default {} }", ParserError, "Expected '{' but got identifier");
 }
 
 BOOST_AUTO_TEST_CASE(for_statement)
@@ -353,10 +353,10 @@ BOOST_AUTO_TEST_CASE(for_statement)
 BOOST_AUTO_TEST_CASE(for_invalid_expression)
 {
 	CHECK_PARSE_ERROR("{ for {} {} {} {} }", ParserError, "Literal, identifier or instruction expected.");
-	CHECK_PARSE_ERROR("{ for 1 1 {} {} }", ParserError, "Expected token LBrace got 'Number'");
-	CHECK_PARSE_ERROR("{ for {} 1 1 {} }", ParserError, "Expected token LBrace got 'Number'");
-	CHECK_PARSE_ERROR("{ for {} 1 {} 1 }", ParserError, "Expected token LBrace got 'Number'");
-	CHECK_PARSE_ERROR("{ for {} mload {} {} }", ParserError, "Expected token \"(\"");
+	CHECK_PARSE_ERROR("{ for 1 1 {} {} }", ParserError, "Expected '{' but got 'Number'");
+	CHECK_PARSE_ERROR("{ for {} 1 1 {} }", ParserError, "Expected '{' but got 'Number'");
+	CHECK_PARSE_ERROR("{ for {} 1 {} 1 }", ParserError, "Expected '{' but got 'Number'");
+	CHECK_PARSE_ERROR("{ for {} mload {} {} }", ParserError, "Expected '(' (instruction \"mload\" expects 1 arguments)");
 	CHECK_PARSE_ERROR("{ for {} mstore(1, 1) {} {} }", ParserError, "Instruction \"mstore\" not allowed in this context");
 }
 
@@ -437,13 +437,13 @@ BOOST_AUTO_TEST_CASE(invalid_tuple_assignment)
 
 BOOST_AUTO_TEST_CASE(instruction_too_few_arguments)
 {
-	CHECK_PARSE_ERROR("{ mul() }", ParserError, "Expected expression (\"mul\" expects 2 arguments)");
-	CHECK_PARSE_ERROR("{ mul(1) }", ParserError, "Expected comma (\"mul\" expects 2 arguments)");
+	CHECK_PARSE_ERROR("{ mul() }", ParserError, "Expected expression (instruction \"mul\" expects 2 arguments)");
+	CHECK_PARSE_ERROR("{ mul(1) }", ParserError, "Expected ',' (instruction \"mul\" expects 2 arguments)");
 }
 
 BOOST_AUTO_TEST_CASE(instruction_too_many_arguments)
 {
-	CHECK_PARSE_ERROR("{ mul(1, 2, 3) }", ParserError, "Expected ')' (\"mul\" expects 2 arguments)");
+	CHECK_PARSE_ERROR("{ mul(1, 2, 3) }", ParserError, "Expected ')' (instruction \"mul\" expects 2 arguments)");
 }
 
 BOOST_AUTO_TEST_CASE(recursion_depth)

test/libsolidity/SolidityParser.cpp

@@ -992,7 +992,7 @@ BOOST_AUTO_TEST_CASE(keyword_is_reserved)
 	for (const auto& keyword: keywords)
 	{
 		auto text = std::string("contract ") + keyword + " {}";
-		CHECK_PARSE_ERROR(text.c_str(), "Expected token Identifier got reserved keyword");
+		CHECK_PARSE_ERROR(text.c_str(), "Expected identifier but got reserved keyword");
 	}
 }
 

test/libsolidity/StandardCompiler.cpp

@@ -326,8 +326,8 @@ BOOST_AUTO_TEST_CASE(compilation_error)
 		{
 			BOOST_CHECK_EQUAL(
 				dev::jsonCompactPrint(error),
-				"{\"component\":\"general\",\"formattedMessage\":\"fileA:1:23: ParserError: Expected token Identifier got 'RBrace'\\n"
-				"contract A { function }\\n                      ^\\n\",\"message\":\"Expected token Identifier got 'RBrace'\","
+				"{\"component\":\"general\",\"formattedMessage\":\"fileA:1:23: ParserError: Expected identifier but got '}'\\n"
+				"contract A { function }\\n                      ^\\n\",\"message\":\"Expected identifier but got '}'\","
 				"\"severity\":\"error\",\"sourceLocation\":{\"end\":22,\"file\":\"fileA\",\"start\":22},\"type\":\"ParserError\"}"
 			);
 		}

test/libsolidity/syntaxTests/functionTypes/function_type_constructor_local.sol

@@ -5,4 +5,4 @@ contract C {
     }
 }
 // ----
-// ParserError: (118-118): Expected token Semicolon got 'Identifier'
+// ParserError: (118-118): Expected ';' but got identifier

test/libsolidity/syntaxTests/parsing/constant_is_keyword.sol

@@ -2,4 +2,4 @@ contract Foo {
 	uint constant = 4;
 }
 // ----
-// ParserError: (30-30): Expected token Identifier got 'Assign'
+// ParserError: (30-30): Expected identifier but got '='

test/libsolidity/syntaxTests/parsing/emit_without_event.sol

@@ -5,4 +5,4 @@ contract C {
 	}
 }
 // ----
-// ParserError: (49-49): Expected token LParen got 'Semicolon'
+// ParserError: (49-49): Expected '(' but got ';'

test/libsolidity/syntaxTests/parsing/event_with_no_argument_list.sol

@@ -2,4 +2,4 @@ contract c {
 	event e;
 }
 // ----
-// ParserError: (21-21): Expected token LParen got 'Semicolon'
+// ParserError: (21-21): Expected '(' but got ';'

test/libsolidity/syntaxTests/parsing/external_variable.sol

@@ -2,4 +2,4 @@ contract c {
 	uint external x;
 }
 // ----
-// ParserError: (19-19): Expected token Identifier got 'External'
+// ParserError: (19-19): Expected identifier but got 'external'

test/libsolidity/syntaxTests/parsing/fixed_literal_with_double_radix.sol

@@ -2,4 +2,4 @@ contract A {
 	fixed40x40 pi = 3.14.15;
 }
 // ----
-// ParserError: (34-34): Expected token Semicolon got 'Number'
+// ParserError: (34-34): Expected ';' but got 'Number'

test/libsolidity/syntaxTests/parsing/function_type_as_storage_variable_with_modifiers.sol

@@ -2,4 +2,4 @@ contract test {
 	function (uint, uint) modifier1() returns (uint) f1;
 }
 // ----
-// ParserError: (66-66): Expected token LBrace got 'Identifier'
+// ParserError: (66-66): Expected '{' but got identifier

test/libsolidity/syntaxTests/parsing/local_const_variable.sol

@@ -6,4 +6,4 @@ contract Foo {
 	}
 }
 // ----
-// ParserError: (67-67): Expected token Semicolon got 'Constant'
+// ParserError: (67-67): Expected ';' but got 'constant'

test/libsolidity/syntaxTests/parsing/location_specifiers_for_state_variables.sol

@@ -2,4 +2,4 @@ contract Foo {
 	uint[] memory x;
 }
 // ----
-// ParserError: (23-23): Expected token Identifier got 'Memory'
+// ParserError: (23-23): Expected identifier but got 'memory'

test/libsolidity/syntaxTests/parsing/malformed_enum_declaration.sol

@@ -2,4 +2,4 @@ contract c {
 	enum foo { WARNING,}
 }
 // ----
-// ParserError: (33-33): Expected Identifier after ','
+// ParserError: (33-33): Expected identifier after ','

test/libsolidity/syntaxTests/parsing/missing_parameter_name_in_named_args.sol

@@ -3,4 +3,4 @@ contract test {
 	function b() returns (uint r) { r = a({: 1, : 2, : 3}); }
 }
 // ----
-// ParserError: (143-143): Expected token Identifier got 'Colon'
+// ParserError: (143-143): Expected identifier but got ':'

test/libsolidity/syntaxTests/parsing/missing_variable_name_in_declaration.sol

@@ -2,4 +2,4 @@ contract test {
     uint256 ;
 }
 // ----
-// ParserError: (28-28): Expected token Identifier got 'Semicolon'
+// ParserError: (28-28): Expected identifier but got ';'

test/libsolidity/syntaxTests/parsing/modifier_without_semicolon.sol

@@ -2,4 +2,4 @@ contract c {
 	modifier mod { if (msg.sender == 0) _ }
 }
 // ----
-// ParserError: (52-52): Expected token Semicolon got 'RBrace'
+// ParserError: (52-52): Expected ';' but got '}'

test/libsolidity/syntaxTests/parsing/payable_accessor.sol

@@ -2,4 +2,4 @@ contract test {
 	uint payable x;
 }
 // ----
-// ParserError: (22-22): Expected token Identifier got 'Payable'
+// ParserError: (22-22): Expected identifier but got 'payable'

test/libsolidity/syntaxTests/parsing/tuples_without_commas.sol

@@ -4,4 +4,4 @@ contract C {
 	}
 }
 // ----
-// ParserError: (42-42): Expected token Comma got 'Number'
+// ParserError: (42-42): Expected ',' but got 'Number'

test/libsolidity/syntaxTests/parsing/var_array.sol

@@ -2,4 +2,4 @@ contract Foo {
 	function f() { var[] a; }
 }
 // ----
-// ParserError: (34-34): Expected token Identifier got 'LBrack'
+// ParserError: (34-34): Expected identifier but got '['