Report meaningful error if parsing a version pragma failed

Changelog.md

@@ -1,12 +1,12 @@
 ### 0.8.1 (unreleased)
 
 Compiler Features:
+ * Parser: Report meaningful error if parsing a version pragma failed.
  * SMTChecker: Support ABI functions as uninterpreted functions.
 
 Bugfixes:
  * SMTChecker: Fix false negatives in overriding modifiers.
 
-
 ### 0.8.0 (2020-12-16)
 
 Breaking Changes:

liblangutil/SemVerHandler.cpp

@@ -147,7 +147,7 @@ bool SemVerMatchExpression::matches(SemVerVersion const& _version) const
 	return false;
 }
 
-SemVerMatchExpression SemVerMatchExpressionParser::parse()
+optional<SemVerMatchExpression> SemVerMatchExpressionParser::parse()
 {
 	reset();
 
@@ -166,6 +166,7 @@ SemVerMatchExpression SemVerMatchExpressionParser::parse()
 	catch (SemVerError const&)
 	{
 		reset();
+		return nullopt;
 	}
 
 	return m_expression;

liblangutil/SemVerHandler.h

@@ -26,6 +26,7 @@
 #include <liblangutil/Token.h>
 
 #include <string>
+#include <optional>
 #include <utility>
 #include <vector>
 
@@ -86,7 +87,9 @@ public:
 	SemVerMatchExpressionParser(std::vector<Token>  _tokens, std::vector<std::string>  _literals):
 		m_tokens(std::move(_tokens)), m_literals(std::move(_literals))
 	{}
-	SemVerMatchExpression parse();
+
+	/// Returns an expression if it was parseable, or nothing otherwise.
+	std::optional<SemVerMatchExpression> parse();
 
 private:
 	void reset();

libsolidity/analysis/SyntaxChecker.cpp

@@ -160,8 +160,10 @@ bool SyntaxChecker::visit(PragmaDirective const& _pragma)
 		vector<string> literals(_pragma.literals().begin() + 1, _pragma.literals().end());
 		SemVerMatchExpressionParser parser(tokens, literals);
 		auto matchExpression = parser.parse();
+		// An unparsable version pragma is an unrecoverable fatal error in the parser.
+		solAssert(matchExpression.has_value(), "");
 		static SemVerVersion const currentVersion{string(VersionString)};
-		if (!matchExpression.matches(currentVersion))
+		if (!matchExpression->matches(currentVersion))
 			m_errorReporter.syntaxError(
 				3997_error,
 				_pragma.location(),

libsolidity/parsing/Parser.cpp

@@ -140,9 +140,16 @@ void Parser::parsePragmaVersion(SourceLocation const& _location, vector<Token> c
 {
 	SemVerMatchExpressionParser parser(_tokens, _literals);
 	auto matchExpression = parser.parse();
+	if (!matchExpression.has_value())
+		m_errorReporter.fatalParserError(
+			1684_error,
+			_location,
+			"Found version pragma, but failed to parse it. "
+			"Please ensure there is a trailing semicolon."
+		);
 	static SemVerVersion const currentVersion{string(VersionString)};
 	// FIXME: only match for major version incompatibility
-	if (!matchExpression.matches(currentVersion))
+	if (!matchExpression->matches(currentVersion))
 		// If m_parserErrorRecovery is true, the same message will appear from SyntaxChecker::visit(),
 		// so we don't need to report anything here.
 		if (!m_parserErrorRecovery)

scripts/test_antlr_grammar.sh

@@ -114,7 +114,7 @@ do
   SOL_FILES+=("$line")
 done < <(
   grep -riL -E \
-    "^\/\/ (Syntax|Type|Declaration)Error|^\/\/ ParserError (2837|3716|3997|5333|6275|6281|6933|7319)|^==== Source:" \
+    "^\/\/ (Syntax|Type|Declaration)Error|^\/\/ ParserError (1684|2837|3716|3997|5333|6275|6281|6933|7319)|^==== Source:" \
     "${ROOT_DIR}/test/libsolidity/syntaxTests" \
     "${ROOT_DIR}/test/libsolidity/semanticTests" |
       grep -v -E 'comments/.*_direction_override.*.sol' |

test/libsolidity/SemVerMatcher.cpp

@@ -58,11 +58,12 @@ SemVerMatchExpression parseExpression(string const& _input)
 	}
 
 	auto expression = SemVerMatchExpressionParser(tokens, literals).parse();
+	BOOST_REQUIRE(expression.has_value());
 	BOOST_CHECK_MESSAGE(
-		expression.isValid(),
+		expression->isValid(),
 		"Expression \"" + _input + "\" did not parse properly."
 	);
-	return expression;
+	return *expression;
 }
 
 }

test/libsolidity/syntaxTests/pragma/broken_version_1.sol

@@ -0,0 +1,3 @@
+pragma solidity ^0^1;
+// ----
+// ParserError 5333: (0-21): Source file requires different compiler version (current compiler is ....

test/libsolidity/syntaxTests/pragma/broken_version_2.sol

@@ -0,0 +1,3 @@
+pragma solidity pragma;
+// ----
+// ParserError 1684: (0-23): Found version pragma, but failed to parse it. Please ensure there is a trailing semicolon.

test/libsolidity/syntaxTests/pragma/broken_version_3.sol

@@ -0,0 +1,4 @@
+pragma solidity #8.0.0;
+// ----
+// ParserError 6281: (16-17): Token incompatible with Solidity parser as part of pragma directive.
+// ParserError 5333: (0-23): Source file requires different compiler version (current compiler is ....

test/libsolidity/syntaxTests/pragma/broken_version_4.sol

@@ -0,0 +1,3 @@
+pragma solidity (8.0.0);
+// ----
+// ParserError 1684: (0-24): Found version pragma, but failed to parse it. Please ensure there is a trailing semicolon.

test/libsolidity/syntaxTests/pragma/broken_version_5.sol

@@ -0,0 +1,3 @@
+pragma solidity 88_;
+// ----
+// ParserError 1684: (0-20): Found version pragma, but failed to parse it. Please ensure there is a trailing semicolon.

test/libsolidity/syntaxTests/pragma/unterminated_pragma.sol

@@ -0,0 +1,3 @@
+pragma solidity 0.4.3
+// ----
+// ParserError 2314: (22-22): Expected ';' but got end of source

test/libsolidity/syntaxTests/pragma/unterminated_version.sol

@@ -0,0 +1,4 @@
+pragma solidity 0.4.3
+pragma abicoder v2;
+// ----
+// ParserError 1684: (0-41): Found version pragma, but failed to parse it. Please ensure there is a trailing semicolon.