Allow duplicated constructor calls, if no arguments; support for multiple inheritance; backwards compatibility.

# tmp

Changelog.md

@@ -9,6 +9,7 @@ Features:
  * Optimizer: Remove useless ``SWAP1`` instruction preceding a commutative instruction (such as ``ADD``, ``MUL``, etc).
  * Optimizer: Replace comparison operators (``LT``, ``GT``, etc) with opposites if preceded by ``SWAP1``, e.g. ``SWAP1 LT`` is replaced with ``GT``.
  * Optimizer: Optimize across ``mload`` if ``msize()`` is not used.
+ * Static Analyzer: Error on duplicated super constructor calls as experimental 0.5.0 feature.
  * Syntax Checker: Issue warning for empty structs (or error as experimental 0.5.0 feature).
  * General: Introduce new constructor syntax using the ``constructor`` keyword as experimental 0.5.0 feature.
  * Inheritance: Error when using empty parenthesis for base class constructors that require arguments as experimental 0.5.0 feature.
@@ -28,7 +29,6 @@ Bugfixes:
  * Type System: Make external library functions accessible.
  * Type System: Prevent encoding of weird types.
  * Static Analyzer: Fix non-deterministic order of unused variable warnings.
- * Static Analyzer: Error on duplicated super constructor calls.
 
 ### 0.4.21 (2018-03-07)
 

libsolidity/analysis/StaticAnalyzer.cpp

@@ -90,33 +90,43 @@ void StaticAnalyzer::endVisit(FunctionDefinition const&)
 	m_localVarUseCount.clear();
 }
 
-bool modifierOverridesInheritanceSpecifier(
-		ContractDefinition const* _contract,
-		ModifierInvocation const& _modifier,
-		InheritanceSpecifier const& _specifier
-)
-{
-	auto parent = _specifier.name().annotation().referencedDeclaration;
-	return _contract == parent && (!_specifier.arguments().empty() || _modifier.arguments().empty());
-}
-
 bool StaticAnalyzer::visit(ModifierInvocation const& _modifier)
 {
 	if (!m_constructor)
 		return true;
 
-	if (auto contract = dynamic_cast<ContractDefinition const*>(_modifier.name()->annotation().referencedDeclaration))
-		for (auto const& specifier: m_currentContract->baseContracts())
-			if (modifierOverridesInheritanceSpecifier(contract, _modifier, *specifier))
-			{
-				SecondarySourceLocation ssl;
-				ssl.append("Overriden constructor call is here:", specifier->location());
+	bool const v050 = m_currentContract->sourceUnit().annotation().experimentalFeatures.count(ExperimentalFeature::V050);
 
-				m_errorReporter.declarationError(
-					_modifier.location(),
-					ssl,
-					"Duplicated super constructor call."
-				);
+	if (auto contract = dynamic_cast<ContractDefinition const*>(_modifier.name()->annotation().referencedDeclaration))
+		for (auto const& base: m_currentContract->annotation().linearizedBaseContracts)
+			for (auto const& specifier: base->baseContracts())
+			{
+				Declaration const* parent = specifier->name().annotation().referencedDeclaration;
+				if (contract == parent && !specifier->arguments().empty())
+				{
+					if (v050)
+					{
+						SecondarySourceLocation ssl;
+						ssl.append("Second constructor call is here:", specifier->location());
+
+						m_errorReporter.declarationError(
+							_modifier.location(),
+							ssl,
+							"Duplicated super constructor call."
+						);
+					}
+					else
+					{
+						SecondarySourceLocation ssl;
+						ssl.append("Overridden constructor call is here:", specifier->location());
+
+						m_errorReporter.warning(
+							_modifier.location(),
+							"Duplicated super constructor calls are deprecated.",
+							ssl
+						);
+					}
+				}
 			}
 
 	return true;

test/libsolidity/syntaxTests/inheritance/allow_empty_duplicated_super_constructor_call.sol

@@ -0,0 +1,3 @@
+contract A { constructor() public { } }
+contract B1 is A { constructor() A() public {  } }
+contract B2 is A { constructor() A public {  } }

test/libsolidity/syntaxTests/inheritance/base_arguments_multiple_inheritance.sol

@@ -0,0 +1,9 @@
+contract Base {
+    constructor(uint) public { }
+}
+contract Base1 is Base(3) {}
+contract Derived is Base, Base1 {
+    constructor(uint i) Base(i) public {}
+}
+// ----
+// Warning: Duplicated super constructor calls are deprecated.

test/libsolidity/syntaxTests/inheritance/duplicated_ancestor_constructor_call.sol

@@ -0,0 +1,5 @@
+contract A { constructor(uint) public { } }
+contract B is A(2) { constructor() public {  } }
+contract C is B { constructor() A(3) public {  } }
+// ----
+// Warning: Duplicated super constructor calls are deprecated.

test/libsolidity/syntaxTests/inheritance/duplicated_ancestor_constructor_call_V050.sol

@@ -0,0 +1,7 @@
+pragma experimental "v0.5.0";
+
+contract A { constructor(uint) public { } }
+contract B is A(2) { constructor() public {  } }
+contract C is B { constructor() A(3) public {  } }
+// ----
+// DeclarationError: Duplicated super constructor call.

test/libsolidity/syntaxTests/inheritance/duplicated_super_constructor_call.sol

@@ -1,4 +1,4 @@
 contract A { constructor(uint) public { } }
 contract B is A(2) { constructor() A(3) public {  } }
 // ----
-// DeclarationError: Duplicated super constructor call.
+// Warning: Duplicated super constructor calls are deprecated.

test/libsolidity/syntaxTests/inheritance/duplicated_super_constructor_call_V050.sol

@@ -0,0 +1,6 @@
+pragma experimental "v0.5.0";
+
+contract A { constructor(uint) public { } }
+contract B is A(2) { constructor() A(3) public {  } }
+// ----
+// DeclarationError: Duplicated super constructor call.

test/libsolidity/syntaxTests/inheritance/duplicated_super_constructor_call_empty.sol

@@ -1,4 +0,0 @@
-contract A { constructor() public { } }
-contract B is A { constructor() A() public {  } }
-// ----
-// DeclarationError: Duplicated super constructor call.

test/libsolidity/syntaxTests/inheritance/duplicated_super_constructor_call_multi.sol

@@ -0,0 +1,7 @@
+contract C { constructor(uint) public {} }
+contract A is C(2) {}
+contract B is C(2) {}
+contract D is A, B { constructor() C(3) public {} }
+// ----
+// Warning: Duplicated super constructor calls are deprecated.
+// Warning: Duplicated super constructor calls are deprecated.