Disallow loos assembly in Solidity by permanently setting it to SyntaxError (from Warning)

Changelog.md

@@ -53,6 +53,7 @@ Breaking Changes:
  * Type Checker: Fallback function must be external. This was already the case in the experimental 0.5.0 mode.
  * Type Checker: Interface functions must be declared external. This was already the case in the experimental 0.5.0 mode.
  * Type Checker: Address members are not included in contract types anymore. An explicit conversion is now required before invoking an ``address`` member from a contract.
+ * Type Checker: Disallow "loose assembly" syntax entirely. This means that jump labels, jumps and non-functional instructions cannot be used anymore.
  * Remove obsolete ``std`` directory from the Solidity repository. This means accessing ``https://github.com/ethereum/soldity/blob/develop/std/*.sol`` (or ``https://github.com/ethereum/solidity/std/*.sol`` in Remix) will not be possible.
  * References Resolver: Turn missing storage locations into an error. This was already the case in the experimental 0.5.0 mode.
  * Syntax Checker: Disallow functions without implementation to use modifiers. This was already the case in the experimental 0.5.0 mode.

libsolidity/analysis/ReferencesResolver.cpp

@@ -277,7 +277,7 @@ bool ReferencesResolver::visit(InlineAssembly const& _inlineAssembly)
 	// Will be re-generated later with correct information
 	// We use the latest EVM version because we will re-run it anyway.
 	assembly::AsmAnalysisInfo analysisInfo;
-	boost::optional<Error::Type> errorTypeForLoose = m_experimental050Mode ? Error::Type::SyntaxError : Error::Type::Warning;
+	boost::optional<Error::Type> errorTypeForLoose = Error::Type::SyntaxError;
 	assembly::AsmAnalyzer(analysisInfo, errorsIgnored, EVMVersion(), errorTypeForLoose, assembly::AsmFlavour::Loose, resolver).analyze(_inlineAssembly.operations());
 	return false;
 }

libsolidity/analysis/TypeChecker.cpp

@@ -927,15 +927,11 @@ bool TypeChecker::visit(InlineAssembly const& _inlineAssembly)
 	};
 	solAssert(!_inlineAssembly.annotation().analysisInfo, "");
 	_inlineAssembly.annotation().analysisInfo = make_shared<assembly::AsmAnalysisInfo>();
-	boost::optional<Error::Type> errorTypeForLoose =
-		m_scope->sourceUnit().annotation().experimentalFeatures.count(ExperimentalFeature::V050) ?
-		Error::Type::SyntaxError :
-		Error::Type::Warning;
 	assembly::AsmAnalyzer analyzer(
 		*_inlineAssembly.annotation().analysisInfo,
 		m_errorReporter,
 		m_evmVersion,
-		errorTypeForLoose,
+		Error::Type::SyntaxError,
 		assembly::AsmFlavour::Loose,
 		identifierAccess
 	);

libsolidity/inlineasm/AsmAnalysis.cpp

@@ -57,7 +57,7 @@ bool AsmAnalyzer::operator()(Label const& _label)
 	solAssert(!_label.name.empty(), "");
 	checkLooseFeature(
 		_label.location,
-		"The use of labels is deprecated. Please use \"if\", \"switch\", \"for\" or function calls instead."
+		"The use of labels is disallowed. Please use \"if\", \"switch\", \"for\" or function calls instead."
 	);
 	m_info.stackHeightInfo[&_label] = m_stackHeight;
 	warnOnInstructions(solidity::Instruction::JUMPDEST, _label.location);
@@ -68,7 +68,7 @@ bool AsmAnalyzer::operator()(assembly::Instruction const& _instruction)
 {
 	checkLooseFeature(
 		_instruction.location,
-		"The use of non-functional instructions is deprecated. Please use functional notation instead."
+		"The use of non-functional instructions is disallowed. Please use functional notation instead."
 	);
 	auto const& info = instructionInfo(_instruction.instruction);
 	m_stackHeight += info.ret - info.args;
@@ -201,7 +201,7 @@ bool AsmAnalyzer::operator()(assembly::StackAssignment const& _assignment)
 {
 	checkLooseFeature(
 		_assignment.location,
-		"The use of stack assignment is deprecated. Please use assignment in functional notation instead."
+		"The use of stack assignment is disallowed. Please use assignment in functional notation instead."
 	);
 	bool success = checkAssignment(_assignment.variableName, size_t(-1));
 	m_info.stackHeightInfo[&_assignment] = m_stackHeight;

test/libsolidity/syntaxTests/nameAndTypeResolution/373_inline_assembly_unbalanced_positive_stack.sol

@@ -6,5 +6,5 @@ contract test {
     }
 }
 // ----
-// Warning: (73-74): Top-level expressions are not supposed to return values (this expression returns 1 value). Use ``pop()`` or assign them.
+// SyntaxError: (73-74): Top-level expressions are not supposed to return values (this expression returns 1 value). Use ``pop()`` or assign them.
 // DeclarationError: (59-84): Unbalanced stack at the end of a block: 1 surplus item(s).

test/libsolidity/syntaxTests/nameAndTypeResolution/374_inline_assembly_unbalanced_negative_stack.sol

@@ -6,5 +6,5 @@ contract test {
     }
 }
 // ----
-// Warning: (73-76): The use of non-functional instructions is deprecated. Please use functional notation instead.
+// SyntaxError: (73-76): The use of non-functional instructions is deprecated. Please use functional notation instead.
 // DeclarationError: (59-86): Unbalanced stack at the end of a block: 1 missing item(s).

test/libsolidity/syntaxTests/nameAndTypeResolution/386_inline_assembly_050_literals_on_stack.sol

@@ -1,11 +0,0 @@
-pragma experimental "v0.5.0";
-contract C {
-    function f() pure public {
-        assembly {
-            1
-        }
-    }
-}
-// ----
-// SyntaxError: (105-106): Top-level expressions are not supposed to return values (this expression returns 1 value). Use ``pop()`` or assign them.
-// DeclarationError: (91-116): Unbalanced stack at the end of a block: 1 surplus item(s).

test/libsolidity/syntaxTests/nameAndTypeResolution/387_inline_assembly_literals_on_stack.sol

@@ -6,5 +6,5 @@ contract C {
     }
 }
 // ----
-// Warning: (75-76): Top-level expressions are not supposed to return values (this expression returns 1 value). Use ``pop()`` or assign them.
+// SyntaxError: (75-76): Top-level expressions are not supposed to return values (this expression returns 1 value). Use ``pop()`` or assign them.
 // DeclarationError: (61-86): Unbalanced stack at the end of a block: 1 surplus item(s).

test/libsolidity/syntaxTests/nameAndTypeResolution/388_inline_assembly_050_bare_instructions.sol

@@ -1,12 +0,0 @@
-pragma experimental "v0.5.0";
-contract C {
-    function f() view public {
-        assembly {
-            address
-            pop
-        }
-    }
-}
-// ----
-// SyntaxError: (105-112): The use of non-functional instructions is deprecated. Please use functional notation instead.
-// SyntaxError: (125-128): The use of non-functional instructions is deprecated. Please use functional notation instead.

test/libsolidity/syntaxTests/nameAndTypeResolution/389_inline_assembly_bare_instructions.sol

@@ -7,5 +7,5 @@ contract C {
     }
 }
 // ----
-// Warning: (75-82): The use of non-functional instructions is deprecated. Please use functional notation instead.
-// Warning: (95-98): The use of non-functional instructions is deprecated. Please use functional notation instead.
+// SyntaxError: (75-82): The use of non-functional instructions is deprecated. Please use functional notation instead.
+// SyntaxError: (95-98): The use of non-functional instructions is deprecated. Please use functional notation instead.

test/libsolidity/syntaxTests/nameAndTypeResolution/390_inline_assembly_050_labels.sol

@@ -1,11 +0,0 @@
-pragma experimental "v0.5.0";
-contract C {
-    function f() pure public {
-        assembly {
-            label:
-        }
-    }
-}
-// ----
-// SyntaxError: (105-110): The use of labels is deprecated. Please use "if", "switch", "for" or function calls instead.
-// SyntaxError: (105-110): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.

test/libsolidity/syntaxTests/nameAndTypeResolution/391_inline_assembly_labels.sol

@@ -6,5 +6,5 @@ contract C {
     }
 }
 // ----
-// Warning: (75-80): The use of labels is deprecated. Please use "if", "switch", "for" or function calls instead.
-// Warning: (75-80): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.
+// SyntaxError: (75-80): The use of labels is deprecated. Please use "if", "switch", "for" or function calls instead.
+// SyntaxError: (75-80): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.

test/libsolidity/syntaxTests/nameAndTypeResolution/393_inline_assembly_jump.sol

@@ -6,5 +6,4 @@ contract C {
     }
 }
 // ----
-// Warning: (75-82): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.
-// TypeError: (75-82): Function declared as pure, but this expression (potentially) modifies the state and thus requires non-payable (the default) or payable.
+// SyntaxError: (75-82): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.

test/libsolidity/syntaxTests/nameAndTypeResolution/395_inline_assembly_leave_items_on_stack.sol

@@ -6,5 +6,5 @@ contract C {
     }
 }
 // ----
-// Warning: (75-83): Top-level expressions are not supposed to return values (this expression returns 1 value). Use ``pop()`` or assign them.
+// SyntaxError: (75-83): Top-level expressions are not supposed to return values (this expression returns 1 value). Use ``pop()`` or assign them.
 // DeclarationError: (61-93): Unbalanced stack at the end of a block: 1 surplus item(s).

test/libsolidity/syntaxTests/viewPureChecker/assembly_jump_no_restrict_warning.sol

@@ -4,4 +4,4 @@ contract C {
     }
 }
 // ----
-// Warning: (58-65): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.
+// SyntaxError: (58-65): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.

test/libsolidity/syntaxTests/viewPureChecker/assembly_jump_view_fail.sol

@@ -4,5 +4,4 @@ contract C {
     }
 }
 // ----
-// Warning: (63-70): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.
-// TypeError: (63-70): Function declared as view, but this expression (potentially) modifies the state and thus requires non-payable (the default) or payable.
+// SyntaxError: (63-70): Jump instructions and labels are low-level EVM features that can lead to incorrect stack access. Because of that they are discouraged. Please consider using "switch", "if" or "for" statements instead.