Derive macro doesn't keep the struct's generics

For this code snippet

struct CpuUsageLabelsSet<'a> {
    mode: CpuMode,   // <- an enum
    service: &'a str,
}

which emits compilation error

error[E0726]: implicit elided lifetime not allowed here
  --> xxxxx
   |
48 | struct CpuUsageLabelSet<'a> { // <-- `'a` lifetime is used in the struct,
   |        ^^^^^^^^^^^^^^^^ expected lifetime parameter
   |
help: indicate the anonymous lifetime
   |
48 | struct CpuUsageLabelSet<'_><'a> { // <-- `'a` lifetime is used in the struct,
   |                        ++++

Reproduce the E0726 error using the CpuUsageLabelsSet example and inspect the derive-macro expansion that handles the struct. The work is done when the generated code preserves the struct's lifetime and other generics so this example compiles without requiring an extra anonymous lifetime.