Stop complaining about shadowing parameters of functions without bodies

Author: a3d4

libsolidity/analysis/DeclarationContainer.cpp

@@ -124,7 +124,10 @@ bool DeclarationContainer::registerDeclaration(
 		// Do not warn about shadowing for structs and enums because their members are
 		// not accessible without prefixes. Also do not warn about event parameters
 		// because they do not participate in any proper scope.
-		bool special = _declaration.scope() && (_declaration.isStructMember() || _declaration.isEnumValue() || _declaration.isEventParameter());
+
+		FunctionDefinition const* functionDefinitionScope = dynamic_cast<FunctionDefinition const*>(_declaration.scope());
+		bool special = _declaration.scope() && (_declaration.isStructMember() || _declaration.isEnumValue() || _declaration.isEventParameter()) ||
+			functionDefinitionScope && !functionDefinitionScope->hasBody(); // parameter of a function without body
 		if (m_enclosingContainer && !special)
 			m_homonymCandidates.emplace_back(*_name, _location ? _location : &_declaration.location());
 	}

libsolidity/ast/AST.h

@@ -853,6 +853,7 @@ class FunctionDefinition: public CallableDeclaration, public StructurallyDocumen
 	Token kind() const { return m_kind; }
 	bool isPayable() const { return m_stateMutability == StateMutability::Payable; }
 	std::vector<ASTPointer<ModifierInvocation>> const& modifiers() const { return m_functionModifiers; }
+	bool hasBody() const { return m_body != nullptr; }
 	Block const& body() const { solAssert(m_body, ""); return *m_body; }
 	Visibility defaultVisibility() const override;
 	bool isVisibleInContract() const override

test/libsolidity/syntaxTests/scoping/name_shadowing4.sol

@@ -0,0 +1,11 @@
+abstract contract A {
+    function f(uint A) public {}       // warning
+    function g(uint A) public virtual; // OK
+}
+
+contract C {
+    function f(uint C) public pure {}  // warning
+}
+// ----
+// Warning 2519: (37-43): This declaration shadows an existing declaration.
+// Warning 2519: (148-154): This declaration shadows an existing declaration.