From 1ea64d6cc05745c5ef5c90d75e71211682aba542 Mon Sep 17 00:00:00 2001
From: Matheus Aguiar <matheus.pit@gmail.com>
Date: Sat, 6 Apr 2024 17:17:51 -0300
Subject: [PATCH] Make parser accept transient as location (but not a keyword)

---
 .../analysis/DeclarationTypeChecker.cpp        | 18 ++++++++++++++++--
 libsolidity/ast/AST.h                          |  2 +-
 libsolidity/ast/ASTJsonExporter.cpp            |  2 ++
 libsolidity/parsing/Parser.cpp                 | 17 +++++++++++++++++
 4 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/libsolidity/analysis/DeclarationTypeChecker.cpp b/libsolidity/analysis/DeclarationTypeChecker.cpp
index 28c051c0a000..8bfd8fdd265f 100644
--- a/libsolidity/analysis/DeclarationTypeChecker.cpp
+++ b/libsolidity/analysis/DeclarationTypeChecker.cpp
@@ -407,6 +407,7 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 			{
 				case Location::Memory: return "\"memory\"";
 				case Location::Storage: return "\"storage\"";
+				case Location::Transient: return "\"transient\"";
 				case Location::CallData: return "\"calldata\"";
 				case Location::Unspecified: return "none";
 			}
@@ -456,8 +457,18 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 	}
 	else if (_variable.isStateVariable())
 	{
-		solAssert(varLoc == Location::Unspecified, "");
-		typeLoc = (_variable.isConstant() || _variable.immutable()) ? DataLocation::Memory : DataLocation::Storage;
+		switch (varLoc)
+		{
+			case Location::Unspecified:
+				typeLoc = (_variable.isConstant() || _variable.immutable()) ? DataLocation::Memory : DataLocation::Storage;
+				break;
+			case Location::Transient:
+				solAssert(false, "Transient storage type checking not implemented yet");
+				break;
+			default:
+				solAssert(false, "");
+				break;
+		}
 	}
 	else if (
 		dynamic_cast<StructDefinition const*>(_variable.scope()) ||
@@ -477,6 +488,9 @@ void DeclarationTypeChecker::endVisit(VariableDeclaration const& _variable)
 			case Location::CallData:
 				typeLoc = DataLocation::CallData;
 				break;
+			case Location::Transient:
+				solAssert(false, "Transient storage type checking not implemented yet");
+				break;
 			case Location::Unspecified:
 				solAssert(!_variable.hasReferenceOrMappingType(), "Data location not properly set.");
 		}
diff --git a/libsolidity/ast/AST.h b/libsolidity/ast/AST.h
index 27926721aa6f..8e6b5f8202a3 100644
--- a/libsolidity/ast/AST.h
+++ b/libsolidity/ast/AST.h
@@ -1053,7 +1053,7 @@ class FunctionDefinition: public CallableDeclaration, public StructurallyDocumen
 class VariableDeclaration: public Declaration, public StructurallyDocumented
 {
 public:
-	enum Location { Unspecified, Storage, Memory, CallData };
+	enum Location { Unspecified, Storage, Transient, Memory, CallData };
 	enum class Mutability { Mutable, Immutable, Constant };
 	static std::string mutabilityToString(Mutability _mutability)
 	{
diff --git a/libsolidity/ast/ASTJsonExporter.cpp b/libsolidity/ast/ASTJsonExporter.cpp
index c54a2d013ad0..6de4f2b55c1e 100644
--- a/libsolidity/ast/ASTJsonExporter.cpp
+++ b/libsolidity/ast/ASTJsonExporter.cpp
@@ -1059,6 +1059,8 @@ std::string ASTJsonExporter::location(VariableDeclaration::Location _location)
 		return "memory";
 	case VariableDeclaration::Location::CallData:
 		return "calldata";
+	case VariableDeclaration::Location::Transient:
+		return "transient";
 	}
 	// To make the compiler happy
 	return {};
diff --git a/libsolidity/parsing/Parser.cpp b/libsolidity/parsing/Parser.cpp
index f650e0dbf1dc..05bb4995b6f2 100644
--- a/libsolidity/parsing/Parser.cpp
+++ b/libsolidity/parsing/Parser.cpp
@@ -899,6 +899,23 @@ ASTPointer<VariableDeclaration> Parser::parseVariableDeclaration(
 	{
 		nodeFactory.markEndPosition();
 		tie(identifier, nameLocation) = expectIdentifierWithLocation();
+		if (
+			*identifier == "transient" &&
+			m_scanner->currentToken() == Token::Identifier &&
+			(
+				_options.allowLocationSpecifier ||
+				_options.kind == VarDeclKind::State
+			)
+		)
+		{
+			if (location != VariableDeclaration::Location::Unspecified)
+				parserError(ErrorId{3548}, "Location already specified.");
+			else
+				location = VariableDeclaration::Location::Transient;
+
+			nodeFactory.markEndPosition();
+			tie(identifier, nameLocation) = expectIdentifierWithLocation();
+		}
 	}
 	ASTPointer<Expression> value;
 	if (_options.allowInitialValue)