Eliminate unnecessary m_source from Parser

Author: christianparpart

liblangutil/Scanner.h

@@ -119,6 +119,8 @@ class Scanner
 		rescan();
 	}
 
+	CharStream const& charStream() const noexcept { return m_source; }
+
 	/// @returns the next token and advances input
 	Token next();
 

libsolidity/parsing/Parser.cpp

@@ -87,7 +87,6 @@ ASTPointer<SourceUnit> Parser::parse(CharStream& _charStream)
 	try
 	{
 		m_recursionDepth = 0;
-		m_source = &_charStream;
 		m_scanner = make_shared<Scanner>(_charStream);
 		ASTNodeFactory nodeFactory(*this);
 
@@ -2057,16 +2056,14 @@ bool Parser::variableDeclarationStart()
 
 optional<string> Parser::findLicenseString(std::vector<ASTPointer<ASTNode>> const& _nodes)
 {
-	solAssert(!!m_source, "");
-
 	// We circumvent the scanner here, because it skips non-docstring comments.
 	static regex const licenseRegex("SPDX-License-Identifier:\\s*([a-zA-Z0-9 ()+.-]+)");
 
 	// Search inside all parts of the source not covered by parsed nodes.
 	// This will leave e.g. "global comments".
 	using iter = std::string::const_iterator;
 	vector<pair<iter, iter>> sequencesToSearch;
-	string const& source = m_source->source();
+	string const& source = m_scanner->charStream().source();
 	sequencesToSearch.emplace_back(source.begin(), source.end());
 	for (ASTPointer<ASTNode> const& node: _nodes)
 		if (node->location().hasText())

libsolidity/parsing/Parser.h

@@ -211,7 +211,6 @@ class Parser: public langutil::ParserBase
 	/// Creates an empty ParameterList at the current location (used if parameters can be omitted).
 	ASTPointer<ParameterList> createEmptyParameterList();
 
-	langutil::CharStream* m_source = nullptr;
 	/// Flag that signifies whether '_' is parsed as a PlaceholderStatement or a regular identifier.
 	bool m_insideModifier = false;
 	langutil::EVMVersion m_evmVersion;