Andreas Osowski contributed to the llvm/clangir repository by addressing a bug in Clang’s TypePrinter related to the placement of preserve calling-convention attributes for function-pointer types. Working primarily in C and C++, Andreas applied skills in AST manipulation and attribute handling to ensure that attributes such as preserve_none, preserve_most, and preserve_all are correctly positioned before the type in generated output, resolving compilation errors. He reinforced the fix by adding regression tests, improving both reliability and test coverage. This focused engineering effort enhanced the predictability of IR and AST generation, reducing debugging time for downstream compiler development workflows.