Learned while listening to Rustacean Station, from the source link below:

Inlining: Performed during the graph generation phase. The inlining heuristic is very simple: basically, if the function being called is known, and it is safe to inline, the function will be inlined. Large functions (>600 source characters including whitespace or 196 AST nodes) will not be inlined. Cumulatively, a total of 196 AST nodes can be inlined in a single function.

This means that adding or removing comments can make a difference to inlining and, therefore, the performance of an application.

Source:

• [1] https://jayconrod.com/posts/54/a-tour-of-v8-crankshaft-the-optimizing-compiler