Merge pull request #4443 from ethereum/double_var_decl_fix

Fix crash when declaring the same var twice in the same scope

6 files changed, 49 insertions, 1 deletions

diff --git a/libsolidity/analysis/DeclarationContainer.cpp b/libsolidity/analysis/DeclarationContainer.cpp
index 786272e4..9e2bf6d3 100644
--- a/libsolidity/analysis/DeclarationContainer.cpp
+++ b/libsolidity/analysis/DeclarationContainer.cpp
@@ -96,6 +96,11 @@ void DeclarationContainer::activateVariable(ASTString const& _name)
 	m_invisibleDeclarations.erase(_name);
 }
 
+bool DeclarationContainer::isInvisible(ASTString const& _name) const
+{
+	return m_invisibleDeclarations.count(_name);
+}
+
 bool DeclarationContainer::registerDeclaration(
 	Declaration const& _declaration,
 	ASTString const* _name,
diff --git a/libsolidity/analysis/DeclarationContainer.h b/libsolidity/analysis/DeclarationContainer.h
index a3e0bd0a..9d7a17a3 100644
--- a/libsolidity/analysis/DeclarationContainer.h
+++ b/libsolidity/analysis/DeclarationContainer.h
@@ -62,6 +62,9 @@ public:
 	/// VariableDeclarationStatements.
 	void activateVariable(ASTString const& _name);
 
+	/// @returns true if declaration is currently invisible.
+	bool isInvisible(ASTString const& _name) const;
+
 	/// @returns existing declaration names similar to @a _name.
 	/// Searches this and all parent containers.
 	std::vector<ASTString> similarNames(ASTString const& _name) const;
diff --git a/libsolidity/analysis/NameAndTypeResolver.cpp b/libsolidity/analysis/NameAndTypeResolver.cpp
index b856544a..7c23c992 100644
--- a/libsolidity/analysis/NameAndTypeResolver.cpp
+++ b/libsolidity/analysis/NameAndTypeResolver.cpp
@@ -156,7 +156,13 @@ bool NameAndTypeResolver::updateDeclaration(Declaration const& _declaration)
 void NameAndTypeResolver::activateVariable(string const& _name)
 {
 	solAssert(m_currentScope, "");
-	m_currentScope->activateVariable(_name);
+	// Scoped local variables are invisible before activation.
+	// When a local variable is activated, its name is removed
+	// from a scope's invisible variables.
+	// This is used to avoid activation of variables of same name
+	// in the same scope (an error is returned).
+	if (m_currentScope->isInvisible(_name))
+		m_currentScope->activateVariable(_name);
 }
 
 vector<Declaration const*> NameAndTypeResolver::resolveName(ASTString const& _name, ASTNode const* _scope) const
diff --git a/test/libsolidity/syntaxTests/scoping/double_variable_declaration_same_and_disjoint_scope.sol b/test/libsolidity/syntaxTests/scoping/double_variable_declaration_same_and_disjoint_scope.sol
new file mode 100644
index 00000000..45c5ff2d
--- /dev/null
+++ b/test/libsolidity/syntaxTests/scoping/double_variable_declaration_same_and_disjoint_scope.sol
@@ -0,0 +1,10 @@
+contract test {
+    function f() pure public {
+        uint x;
+        { uint x; }
+        uint x;
+    }
+}
+// ----
+// Warning: (73-79): This declaration shadows an existing declaration.
+// DeclarationError: (91-97): Identifier already declared.
diff --git a/test/libsolidity/syntaxTests/scoping/double_variable_declaration_same_scope.sol b/test/libsolidity/syntaxTests/scoping/double_variable_declaration_same_scope.sol
new file mode 100644
index 00000000..72c31f73
--- /dev/null
+++ b/test/libsolidity/syntaxTests/scoping/double_variable_declaration_same_scope.sol
@@ -0,0 +1,8 @@
+contract test {
+    function f() pure public {
+        uint x;
+        uint x;
+    }
+}
+// ----
+// DeclarationError: (71-77): Identifier already declared.
diff --git a/test/libsolidity/syntaxTests/scoping/poly_variable_declaration_same_scope.sol b/test/libsolidity/syntaxTests/scoping/poly_variable_declaration_same_scope.sol
new file mode 100644
index 00000000..e414f611
--- /dev/null
+++ b/test/libsolidity/syntaxTests/scoping/poly_variable_declaration_same_scope.sol
@@ -0,0 +1,16 @@
+contract test {
+    function f() pure public {
+        uint x;
+        uint x;
+        uint x;
+        uint x;
+        uint x;
+        uint x;
+    }
+}
+// ----
+// DeclarationError: (71-77): Identifier already declared.
+// DeclarationError: (87-93): Identifier already declared.
+// DeclarationError: (103-109): Identifier already declared.
+// DeclarationError: (119-125): Identifier already declared.
+// DeclarationError: (135-141): Identifier already declared.