diff --git a/docs/Solidity.g4 b/docs/Solidity.g4
index 239cbbdd3..b2f2303ff 100644
--- a/docs/Solidity.g4
+++ b/docs/Solidity.g4
@@ -48,7 +48,6 @@ importDeclaration
 
 interfaceDefinition
   : 'interface' identifier 'from' StringLiteralFragment
-  | 'interface' identifier 'as' AbiString
   | 'interface' identifier contractInheritanceDefinition? contractBody ;
 
 AbiString
diff --git a/liblangutil/Scanner.h b/liblangutil/Scanner.h
index 5e613cfdf..3429f1802 100644
--- a/liblangutil/Scanner.h
+++ b/liblangutil/Scanner.h
@@ -132,6 +132,15 @@ public:
 		return ElementaryTypeNameToken(m_tokens[Current].token, firstSize, secondSize);
 	}
 
+	/// Tests if current keyword is an identifier and matches the given value @p _name.
+	///
+	/// This is best used for directives that cannot be reserved as keywords but
+	/// in some context should be treated like one.
+	bool isIdentifier(std::string const& _name) const
+	{
+		return currentToken() == Token::Identifier && currentLiteral() == _name;
+	}
+
 	SourceLocation currentLocation() const { return m_tokens[Current].location; }
 	std::string const& currentLiteral() const { return m_tokens[Current].literal; }
 	std::tuple<unsigned, unsigned> const& currentTokenInfo() const { return m_tokens[Current].extendedTokenInfo; }
diff --git a/liblangutil/Token.h b/liblangutil/Token.h
index cdc04bb35..d9d4471cb 100644
--- a/liblangutil/Token.h
+++ b/liblangutil/Token.h
@@ -160,7 +160,6 @@ namespace solidity::langutil
 	K(External, "external", 0)                                         \
 	K(Fallback, "fallback", 0)                                         \
 	K(For, "for", 0)                                                   \
-	K(From, "from", 0)                                                 \
 	K(Function, "function", 0)                                         \
 	K(Hex, "hex", 0)                                                   \
 	K(If, "if", 0)                                                     \
diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index cecf6afb9..6a7c3cb19 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -171,7 +171,7 @@ public:
 	SourceUnitAnnotation& annotation() const override;
 
 	std::optional<std::string> const& licenseString() const { return m_licenseString; }
-	std::vector<ASTPointer<ASTNode>> nodes() const { return m_nodes; }
+	std::vector<ASTPointer<ASTNode>> const& nodes() const { return m_nodes; }
 
 	/// Replaces given top-level AST node with a new AST node.
 	void replaceNode(ASTPointer<ASTNode> _oldNode, ASTPointer<ASTNode> _newNode);
@@ -453,6 +453,24 @@ protected:
 
 /// @}
 
+class ImportedContractDefinition: public Declaration
+{
+public:
+	ImportedContractDefinition(
+		int64_t _id,
+		SourceLocation const& _location,
+		ASTPointer<ASTString> const& _name,
+		ASTPointer<ASTString> const& _path
+	);
+
+	void accept(ASTVisitor& _visitor) override;
+	void accept(ASTConstVisitor& _visitor) const override;
+
+private:
+	ASTPointer<ASTString> m_name;
+	ASTPointer<ASTString> m_path;
+};
+
 /**
  * Definition of a contract or library. This is the only AST nodes where child nodes are not visited in
  * document order. It first visits all struct declarations, then all variable declarations and
diff --git a/libsolidity/interface/CompilerStack.cpp b/libsolidity/interface/CompilerStack.cpp
index 7e5a24dd9..f38d83420 100644
--- a/libsolidity/interface/CompilerStack.cpp
+++ b/libsolidity/interface/CompilerStack.cpp
@@ -278,9 +278,12 @@ void CompilerStack::loadMissingInterfaces()
 {
 	for (auto const& sourcePair: m_sources)
 	{
-		ASTPointer<SourceUnit> const& source = sourcePair.second.ast;;
+		ASTPointer<SourceUnit> const& source = sourcePair.second.ast;
+		if (!source)
+			// This can happen if the input source code contained invalid source code.
+			continue;
 
-		for (auto const& astNode: source->nodes())
+		for (ASTPointer<ASTNode> const& astNode: source->nodes())
 		{
 			if (auto* contract = dynamic_cast<ContractDefinition*>(astNode.get()))
 			{
diff --git a/libsolidity/parsing/Parser.cpp b/libsolidity/parsing/Parser.cpp
index 85016db79..47a216a09 100644
--- a/libsolidity/parsing/Parser.cpp
+++ b/libsolidity/parsing/Parser.cpp
@@ -250,7 +250,7 @@ ASTPointer<ImportDirective> Parser::parseImportDirective()
 			fatalParserError(9478_error, "Expected string literal (path), \"*\" or alias list.");
 		// "from" is not a keyword but parsed as an identifier because of backwards
 		// compatibility and because it is a really common word.
-		if (m_scanner->currentToken() != Token::Identifier || m_scanner->currentLiteral() != "from")
+		if (!m_scanner->isIdentifier("from"))
 			fatalParserError(8208_error, "Expected \"from\".");
 		m_scanner->next();
 		if (m_scanner->currentToken() != Token::StringLiteral)
@@ -307,7 +307,7 @@ ASTPointer<ContractDefinition> Parser::parseInterfaceDefinition()
 	ASTPointer<StructuredDocumentation> documentation = parseStructuredDocumentation();
 	vector<ASTPointer<InheritanceSpecifier>> baseContracts;
 
-	if (m_scanner->currentToken() == Token::From)
+	if (m_scanner->isIdentifier("from"))
 	{
 		m_scanner->next();
 		if (m_scanner->currentToken() != Token::StringLiteral)