ASTParser.createBindings does not direct such requests to the current unitResolver, but rather uses the ECJ implementation with no opportunity to override it. I have moved the method into ASTParser ...
When I'm using ASTParser.createAST org.eclipse.jdt:org.eclipse.jdt.core:3.36.0 (instead of 3.35.0). So the ASTParser does not call back the FileASTRequestor for the file having the missing type, and ...