Function grouper is a requirement for the VarNameCleaner.

libyul/optimiser/Suite.cpp

@@ -198,6 +198,7 @@ void OptimiserSuite::run(
 	BlockFlattener{}(ast);
 	DeadCodeEliminator{}(ast);
 
+	FunctionGrouper{}(ast);
 	VarNameCleaner{ast, *_dialect, reservedIdentifiers}(ast);
 	yul::AsmAnalyzer::analyzeStrictAssertCorrect(_dialect, ast);
 

libyul/optimiser/VarNameCleaner.h

@@ -38,7 +38,7 @@ struct Dialect;
  * renumbered by their base name.
  * Function names are not modified.
  *
- * Prerequisites: Disambiguator, FunctionHoister
+ * Prerequisites: Disambiguator, FunctionHoister, FunctionGrouper
  */
 class VarNameCleaner: public ASTModifier
 {