don't lint snake-case on executable crate name

Author: GilShoshan94

compiler/rustc_lint/src/nonstandard_style.rs

@@ -10,6 +10,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{GenericParamKind, PatKind};
 use rustc_middle::ty;
+use rustc_session::config::CrateType;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::{BytePos, Span};
@@ -366,7 +367,11 @@ impl<'tcx> LateLintPass<'tcx> for NonSnakeCase {
                 })
         };
 
-        if let Some(ident) = &crate_ident {
+        if let Some(ident) = &crate_ident
+            && cx.tcx.sess.crate_types().iter().all(|&crate_type| {
+                crate_type != CrateType::Executable
+            })
+        {
             self.check_snake_case(cx, "crate", ident);
         }
     }