Emit warnings for keywords selected to be reserved in the future

Changelog.md

@@ -1,6 +1,8 @@
 ### 0.8.32 (unreleased)
 
 Language Features:
+* Syntax Checker: Warn about identifiers selected for future promotion to Solidity keywords.
+* Yul Analyzer: Warn about identifiers selected for future promotion to Yul keywords.
 
 Compiler Features:
 

docs/assembly.rst

@@ -46,6 +46,7 @@ Solidity language without a compiler change.
     pragma solidity >=0.4.16 <0.9.0;
 
     library GetCode {
+        // This will report a warning - `at` will be promoted to reserved keyword
         function at(address addr) public view returns (bytes memory code) {
             assembly {
                 // retrieve the size of the code, this needs assembly

docs/units-and-global-variables.rst

@@ -430,3 +430,12 @@ These keywords are reserved in Solidity. They might become part of the syntax in
 ``mutable``, ``null``, ``of``, ``partial``, ``promise``, ``reference``, ``relocatable``,
 ``sealed``, ``sizeof``, ``static``, ``supports``, ``switch``, ``typedef``, ``typeof``,
 ``var``.
+
+.. note::
+    The following identifiers will become unavailable in the future due to already being part of
+    the language syntax and thus selected to become Solidity keywords:
+    ``transient``, ``layout``, ``at``, ``error``, ``super``, ``this``.
+
+    There are also Yul identifiers which are selected to become keywords in the future:
+    ``leave``, ``basefee``, ``prevrandao``, ``blobbasefee``, ``blobhash``, ``mcopy``, ``tstore``, ``tload``.
+

liblangutil/Token.cpp

@@ -152,6 +152,40 @@ bool isYulKeyword(std::string_view const _literal)
 	return _literal == "leave" || isYulKeyword(keywordByName(_literal));
 }
 
+bool isFutureSolidityKeyword(std::string const& _literal)
+{
+	std::set<std::string> const futureSolidityKeywords = {
+		"transient",
+		"layout",
+		"at",
+		"error",
+		"super",
+		"this"
+	};
+	return futureSolidityKeywords.contains(_literal);
+}
+
+bool isFutureYulKeyword(std::string const& _literal)
+{
+	return _literal == "leave";
+}
+
+bool isFutureYulReservedIdentifier(std::string const& _literal)
+{
+	std::set<std::string> futureReservedIdentifier = {
+		"basefee",
+		"blobbasefee",
+		"blobhash",
+		"clz",
+		"mcopy",
+		"memoryguard",
+		"prevrandao",
+		"tload",
+		"tstore",
+	};
+	return futureReservedIdentifier.contains(_literal);
+}
+
 std::tuple<Token, unsigned int, unsigned int> fromIdentifierOrKeyword(std::string const& _literal)
 {
 	// Used for `bytesM`, `uintM`, `intM`, `fixedMxN`, `ufixedMxN`.

liblangutil/Token.h

@@ -379,6 +379,12 @@ namespace TokenTraits
 
 	bool isYulKeyword(std::string_view _literal);
 
+	bool isFutureSolidityKeyword(std::string const& _literal);
+
+	bool isFutureYulKeyword(std::string const& _literal);
+
+	bool isFutureYulReservedIdentifier(std::string const& _literal);
+
 	Token AssignmentToBinaryOp(Token op);
 
 	// @returns the precedence > 0 for binary and compare

libsolidity/analysis/NameAndTypeResolver.cpp

@@ -561,6 +561,20 @@ bool DeclarationRegistrationHelper::registerDeclaration(
 			);
 	}
 
+	if (
+		TokenTraits::isFutureSolidityKeyword(name) ||
+		TokenTraits::isFutureYulKeyword(name)
+	)
+		_errorReporter.warning(
+			6335_error,
+			_declaration.location(),
+			fmt::format(
+				"\"{}\" will be promoted to keyword in the next breaking version"
+				" and will not be allowed as an identifier anymore.",
+				name
+			)
+		);
+
 	if (!_container.registerDeclaration(_declaration, _name, _errorLocation, !_declaration.isVisibleInContract() || _inactive, false))
 	{
 		SourceLocation firstDeclarationLocation;

libsolidity/analysis/SyntaxChecker.cpp

@@ -409,6 +409,7 @@ bool SyntaxChecker::visit(ContractDefinition const& _contract)
 				"Functions are not allowed to have the same name as the contract. "
 				"If you intend this to be a constructor, use \"constructor(...) { ... }\" to define it."
 			);
+
 	return true;
 }
 

libyul/AsmAnalysis.cpp

@@ -30,6 +30,7 @@
 #include <libyul/ScopeFiller.h>
 
 #include <liblangutil/ErrorReporter.h>
+#include <liblangutil/Token.h>
 
 #include <libsolutil/CommonData.h>
 #include <libsolutil/StringUtils.h>
@@ -296,9 +297,7 @@ void AsmAnalyzer::operator()(VariableDeclaration const& _varDecl)
 				m_currentScope->insideFunction()
 			);
 	for (auto const& variable: _varDecl.variables)
-	{
 		expectValidIdentifier(variable.name, nativeLocationOf(variable));
-	}
 
 	if (_varDecl.value)
 	{
@@ -745,6 +744,8 @@ void AsmAnalyzer::expectValidIdentifier(YulName _identifier, SourceLocation cons
 			_location,
 			fmt::format("The identifier \"{}\" is reserved and can not be used.", label)
 		);
+
+	checkFutureReservedKeywordOrIdentifier(_identifier, _location);
 }
 
 bool AsmAnalyzer::validateInstructions(std::string_view _instructionIdentifier, langutil::SourceLocation const& _location)
@@ -953,3 +954,21 @@ void AsmAnalyzer::validateObjectStructure(langutil::SourceLocation const& _astRo
 		}
 	}
 }
+
+void AsmAnalyzer::checkFutureReservedKeywordOrIdentifier(YulName _identifier, langutil::SourceLocation const& _location)
+{
+	if (
+		TokenTraits::isFutureYulKeyword(_identifier.str()) ||
+		TokenTraits::isFutureYulReservedIdentifier(_identifier.str())
+	)
+		m_errorReporter.warning(
+			5470_error,
+			_location,
+			fmt::format(
+				"\"{}\" will be promoted to reserved Yul {} in the next breaking version "
+				"and will not be allowed anymore as an identifier.",
+				_identifier.str(),
+				(TokenTraits::isFutureYulKeyword(_identifier.str()) ? "keyword" : "identifier")
+			)
+		);
+}

libyul/AsmAnalysis.h

@@ -128,6 +128,8 @@ class AsmAnalyzer
 
 	void validateObjectStructure(langutil::SourceLocation const& _astRootLocation);
 
+	void checkFutureReservedKeywordOrIdentifier(YulName _identifier, langutil::SourceLocation const& _location);
+
 	yul::ExternalIdentifierAccess::Resolver m_resolver;
 	Scope* m_currentScope = nullptr;
 	/// Variables that are active at the current point in assembly (as opposed to

test/cmdlineTests/memoryguard_shadowing_by_inline_assembly_identifiers/err

@@ -0,0 +1,23 @@
+Warning: "memoryguard" will be promoted to reserved Yul identifier in the next breaking version and will not be allowed anymore as an identifier.
+  --> input.sol:10:20:
+   |
+10 |         assembly { function memoryguard() {} }
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Warning: "memoryguard" will be promoted to reserved Yul identifier in the next breaking version and will not be allowed anymore as an identifier.
+  --> input.sol:11:31:
+   |
+11 |         assembly { function f(memoryguard) {} }
+   |                               ^^^^^^^^^^^
+
+Warning: "memoryguard" will be promoted to reserved Yul identifier in the next breaking version and will not be allowed anymore as an identifier.
+  --> input.sol:12:36:
+   |
+12 |         assembly { function f() -> memoryguard {} }
+   |                                    ^^^^^^^^^^^
+
+Warning: "memoryguard" will be promoted to reserved Yul identifier in the next breaking version and will not be allowed anymore as an identifier.
+  --> input.sol:13:24:
+   |
+13 |         assembly { let memoryguard }
+   |                        ^^^^^^^^^^^

test/externalTests/zeppelin.sh

@@ -116,7 +116,7 @@ function zeppelin_test
             const result = await runSuper(args);
 
             result.output.errors = (result.output.errors || []).filter(err => {
-                if (err.severity === "warning" && err.message.includes("deprecated")) {
+                if (err.severity === "warning" && (err.message.includes("deprecated") || err.message.includes("promoted"))) {
                     return false; // suppress this warning
                 }
                 return true;

test/libsolidity/syntaxTests/constants/constant_state_variable_named_transient.sol

@@ -2,3 +2,4 @@ contract C {
     int constant public transient = 0;
 }
 // ----
+// Warning 6335: (17-50): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/dataLocations/data_location_in_function_type_fail.sol

@@ -7,5 +7,6 @@ library L {
 
 // ----
 // Warning 6162: (251-267): Naming function type parameters is deprecated.
+// Warning 6335: (251-267): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (159-173): Data location must be "memory" or "calldata" for parameter in function, but "storage" was given.
 // TypeError 6651: (251-267): Data location must be "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/externalFunction/function_argument_location_specifier_test_external_transient.sol

@@ -2,4 +2,5 @@ contract test {
     function f(bytes transient) external;
 }
 // ----
+// Warning 6335: (31-46): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (31-46): Data location must be "memory" or "calldata" for parameter in external function, but none was given.

test/libsolidity/syntaxTests/dataLocations/internalFunction/function_argument_location_specifier_test_internal_transient.sol

@@ -2,4 +2,5 @@ contract test {
     function f(bytes transient) internal {}
 }
 // ----
+// Warning 6335: (31-46): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (31-46): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/libraries/library_function_with_data_location_transient.sol

@@ -9,6 +9,14 @@ library L {
     function i2() external pure returns (uint[] transient) { }
 }
 // ----
+// Warning 6335: (28-44): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (103-119): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (141-157): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (218-234): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (256-272): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (329-345): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (367-383): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (444-460): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (28-44): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.
 // TypeError 6651: (103-119): Data location must be "storage", "memory" or "calldata" for return parameter in function, but none was given.
 // TypeError 6651: (141-157): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/libraryExternalFunction/function_argument_location_specifier_test_external_transient.sol

@@ -2,4 +2,5 @@ library test {
     function f(bytes transient) external {}
 }
 // ----
+// Warning 6335: (30-45): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (30-45): Data location must be "storage", "memory" or "calldata" for parameter in external function, but none was given.

test/libsolidity/syntaxTests/dataLocations/libraryInternalFunction/function_argument_location_specifier_test_internal_transient.sol

@@ -2,4 +2,5 @@ library test {
     function f(bytes transient) internal pure {}
 }
 // ----
+// Warning 6335: (30-45): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (30-45): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/privateFunction/private_function_parameters_location_transient.sol

@@ -2,4 +2,5 @@ contract C {
     function f(uint[] transient) private pure {}
 }
 // ----
+// Warning 6335: (28-44): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (28-44): Data location must be "storage", "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/privateFunction/private_function_return_parameters_location_transient.sol

@@ -2,4 +2,5 @@ contract C {
     function f() private pure returns (uint[] transient) {}
 }
 // ----
+// Warning 6335: (52-68): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (52-68): Data location must be "storage", "memory" or "calldata" for return parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/publicFunction/function_argument_location_specifier_test_public_transient.sol

@@ -2,4 +2,5 @@ contract test {
     function f(bytes transient) public;
 }
 // ----
+// Warning 6335: (31-46): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (31-46): Data location must be "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/publicFunction/public_function_return_parameters_location_transient.sol

@@ -2,4 +2,5 @@ contract C {
     function h() public pure returns(uint[] transient) {}
 }
 // ----
+// Warning 6335: (50-66): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (50-66): Data location must be "memory" or "calldata" for return parameter in function, but none was given.

test/libsolidity/syntaxTests/dataLocations/transient_function_type_parameter.sol

@@ -3,3 +3,4 @@ contract C {
 }
 // ----
 // Warning 6162: (27-41): Naming function type parameters is deprecated.
+// Warning 6335: (27-41): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/duplicateFunctions/illegal_names_exception.sol

@@ -8,5 +8,7 @@ contract C {
 	}
 }
 // ----
+// Warning 6335: (61-88): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (90-118): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // Warning 2319: (61-88): This declaration shadows a builtin symbol.
 // Warning 2319: (90-118): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/duplicateFunctions/illegal_names_functions.sol

@@ -12,6 +12,8 @@ contract C {
 // ----
 // DeclarationError 3726: (17-78): The name "_" is reserved.
 // DeclarationError 3726: (84-117): The name "super" is reserved.
+// Warning 6335: (84-117): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (123-155): The name "this" is reserved.
+// Warning 6335: (123-155): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // Warning 2319: (84-117): This declaration shadows a builtin symbol.
 // Warning 2319: (123-155): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/enums/enum_name_future_keyword_warning.sol

@@ -0,0 +1,6 @@
+enum error { layout, at }
+/// ----
+// ----
+// Warning 6335: (0-25): "error" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (13-19): "layout" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (21-23): "at" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/enums/illegal_names.sol

@@ -22,10 +22,14 @@ contract C {
 }
 // ----
 // DeclarationError 3726: (0-19): The name "this" is reserved.
+// Warning 6335: (0-19): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (20-40): The name "super" is reserved.
+// Warning 6335: (20-40): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (41-57): The name "_" is reserved.
 // DeclarationError 3726: (72-76): The name "this" is reserved.
+// Warning 6335: (72-76): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (82-87): The name "super" is reserved.
+// Warning 6335: (82-87): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (93-94): The name "_" is reserved.
 // Warning 2319: (0-19): This declaration shadows a builtin symbol.
 // Warning 2319: (20-40): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/errors/struct_named_error.sol

@@ -4,3 +4,4 @@ contract C {
     error x;
 }
 // ----
+// Warning 6335: (52-74): "error" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/events/illegal_names_exception.sol

@@ -5,5 +5,7 @@ contract C {
 	event _();
 }
 // ----
+// Warning 6335: (80-93): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (95-109): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // Warning 2319: (80-93): This declaration shadows a builtin symbol.
 // Warning 2319: (95-109): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/events/illegal_names_exception_file_level.sol

@@ -2,3 +2,6 @@
 event this();
 event super();
 event _();
+// ----
+// Warning 6335: (66-79): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (80-94): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/freeFunctions/illegal_names.sol

@@ -11,7 +11,9 @@ contract C {
 }
 // ----
 // DeclarationError 3726: (0-18): The name "this" is reserved.
+// Warning 6335: (0-18): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (19-38): The name "super" is reserved.
+// Warning 6335: (19-38): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (39-54): The name "_" is reserved.
 // Warning 2319: (0-18): This declaration shadows a builtin symbol.
 // Warning 2319: (19-38): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/functionTypes/function_type_with_transient_param.sol

@@ -5,4 +5,6 @@ contract C {
 // ----
 // Warning 6162: (27-41): Naming function type parameters is deprecated.
 // Warning 6162: (69-85): Naming function type parameters is deprecated.
+// Warning 6335: (27-41): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 6335: (69-85): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // TypeError 6651: (69-85): Data location must be "memory" or "calldata" for parameter in function, but none was given.

test/libsolidity/syntaxTests/immutable/illegal_names.sol

@@ -5,7 +5,9 @@ contract C {
 }
 // ----
 // DeclarationError 3726: (17-37): The name "super" is reserved.
+// Warning 6335: (17-37): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // DeclarationError 3726: (43-59): The name "_" is reserved.
 // DeclarationError 3726: (65-84): The name "this" is reserved.
+// Warning 6335: (65-84): "this" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
 // Warning 2319: (17-37): This declaration shadows a builtin symbol.
 // Warning 2319: (65-84): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/immutable/immutable_state_var_named_transient.sol

@@ -2,3 +2,4 @@ contract C {
     address public immutable transient;
 }
 // ----
+// Warning 6335: (17-51): "transient" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/imports/import_alias_name_future_keyword_warning.sol

@@ -0,0 +1,7 @@
+==== Source: a ====
+contract A {}
+==== Source: b ====
+import {A as layout} from "a";
+contract C is layout {}
+// ----
+// Warning 6335: (a:0-13): "layout" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.

test/libsolidity/syntaxTests/imports/import_name_future_keyword_warning.sol

@@ -0,0 +1,11 @@
+==== Source: a ====
+uint constant CONST = 10;
+==== Source: b ====
+import "a" as super;
+contract C {
+    uint x = super.CONST;
+}
+// ----
+// DeclarationError 3726: (b:0-20): The name "super" is reserved.
+// Warning 6335: (b:0-20): "super" will be promoted to keyword in the next breaking version and will not be allowed as an identifier anymore.
+// Warning 2319: (b:0-20): This declaration shadows a builtin symbol.