Tree#toString shouldn't be used for Trees deriving from the code being compiled, as it discards whitespace and comments.

This check only runs inside Error Prone code. Suggested replacements include:

• Prefer VisitorState#getConstantExpression for escaping constants in generated code.
• VisitorState#getSourceForNode : it will give you the original source text. Note that for synthetic trees (e.g.: implicit constructors), that source may be null.
• If the string representation was being used for comparison with keywords like this and super, try tree.getName().contentEquals("this")
• One can also get the symbol name and use it for comparison : ASTHelpers.getSymbol(tree).getSimpleName().toString()