In my understanding implicit conversion is done in semantic analysis, but clang AST command clang -Xclang -ast-dump -fsyntax-only file.cpp produces type conversion information in AST, like these two:
...
`- ImplicitCastExpr 0x7fdc27050558 <col:14> 'int' <LValueToRValue>
......
ImplicitCastExpr 0x7f878884c2d0 <col:19> 'unsigned int' <IntegralCast>
...
hence the question.
Implicit type conversion usually occurs in the semantic analysis(more specifically type checking) of a compiler but some can happen in the parsing to make a simpler AST (converting literals to their values directly and so on).
If you look specifcally at the command option you used we see that it means
-fsyntax-only Run the preprocessor, parser and type checking stages.
https://clang.llvm.org/docs/CommandGuide/clang.html
so we see that we expect type information(which requires implicit conversion) to be outputted.
NOTE: I may be unclear, but type checking is just a stage of semantic analysis.
