diff --git a/libyul/optimiser/SSAValueTracker.cpp b/libyul/optimiser/SSAValueTracker.cpp
index 35b29b042..ef96c3796 100644
--- a/libyul/optimiser/SSAValueTracker.cpp
+++ b/libyul/optimiser/SSAValueTracker.cpp
@@ -37,7 +37,7 @@ void SSAValueTracker::operator()(VariableDeclaration const& _varDecl)
 {
 	if (_varDecl.variables.size() == 1)
 		setValue(_varDecl.variables.front().name, _varDecl.value.get());
-	else
+	else if (!_varDecl.value)
 		for (auto const& var: _varDecl.variables)
 			setValue(var.name, nullptr);
 }
diff --git a/libyul/optimiser/SSAValueTracker.h b/libyul/optimiser/SSAValueTracker.h
index e182e0133..efec22008 100644
--- a/libyul/optimiser/SSAValueTracker.h
+++ b/libyul/optimiser/SSAValueTracker.h
@@ -33,6 +33,8 @@ namespace yul
  * Class that walks the AST and stores the initial value of each variable
  * that is never assigned to.
  *
+ * Default value is represented as nullptr.
+ *
  * Prerequisite: Disambiguator
  */
 class SSAValueTracker: public ASTWalker