Function is_in_const_context 

pub fn is_in_const_context(cx: &LateContext<'_>) -> bool

Checks if we are currently in a const context (e.g. const fn, static/const initializer).

The current context is determined based on the current body which is set before calling a lint’s entry point (any function on LateLintPass). If you need to check in a different context use tcx.hir_is_inside_const_context(_).

Do not call this unless the LateContext has an enclosing body. For release build this case will safely return false, but debug builds will ICE. Note that check_expr, check_block, check_pat and a few other entry points will always have an enclosing body. Some entry points like check_path or check_ty may or may not have one.