Rename DivergingFallbackBehavior variants and don't use ::*

compiler/rustc_hir_typeck/src/fallback.rs

@@ -18,12 +18,12 @@
 #[derive(Copy, Clone)]
 pub enum DivergingFallbackBehavior {
     /// Always fallback to `()` (aka "always spontaneous decay")
-    FallbackToUnit,
+    ToUnit,
     /// Sometimes fallback to `!`, but mainly fallback to `()` so that most of the crates are not broken.
-    FallbackToNiko,
+    ContextDependent,
     /// Always fallback to `!` (which should be equivalent to never falling back + not making
     /// never-to-any coercions unless necessary)
-    FallbackToNever,
+    ToNever,
     /// Don't fallback at all
     NoFallback,
 }
@@ -403,13 +403,12 @@ fn calculate_diverging_fallback(
                 diverging_fallback.insert(diverging_ty, ty);
             };
 
-            use DivergingFallbackBehavior::*;
             match behavior {
-                FallbackToUnit => {
+                DivergingFallbackBehavior::ToUnit => {
                     debug!("fallback to () - legacy: {:?}", diverging_vid);
                     fallback_to(self.tcx.types.unit);
                 }
-                FallbackToNiko => {
+                DivergingFallbackBehavior::ContextDependent => {
                     if found_infer_var_info.self_in_trait && found_infer_var_info.output {
                         // This case falls back to () to ensure that the code pattern in
                         // tests/ui/never_type/fallback-closure-ret.rs continues to
@@ -445,14 +444,14 @@ fn calculate_diverging_fallback(
                         fallback_to(self.tcx.types.never);
                     }
                 }
-                FallbackToNever => {
+                DivergingFallbackBehavior::ToNever => {
                     debug!(
                         "fallback to ! - `rustc_never_type_mode = \"fallback_to_never\")`: {:?}",
                         diverging_vid
                     );
                     fallback_to(self.tcx.types.never);
                 }
-                NoFallback => {
+                DivergingFallbackBehavior::NoFallback => {
                     debug!(
                         "no fallback - `rustc_never_type_mode = \"no_fallback\"`: {:?}",
                         diverging_vid

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -390,27 +390,23 @@ fn never_type_behavior(tcx: TyCtxt<'_>) -> (DivergingFallbackBehavior, Diverging
 
 /// Returns the default fallback which is used when there is no explicit override via `#![never_type_options(...)]`.
 fn default_fallback(tcx: TyCtxt<'_>) -> DivergingFallbackBehavior {
-    use DivergingFallbackBehavior::*;
-
     // Edition 2024: fallback to `!`
     if tcx.sess.edition().at_least_rust_2024() {
-        return FallbackToNever;
+        return DivergingFallbackBehavior::ToNever;
     }
 
     // `feature(never_type_fallback)`: fallback to `!` or `()` trying to not break stuff
     if tcx.features().never_type_fallback {
-        return FallbackToNiko;
+        return DivergingFallbackBehavior::ContextDependent;
     }
 
     // Otherwise: fallback to `()`
-    FallbackToUnit
+    DivergingFallbackBehavior::ToUnit
 }
 
 fn parse_never_type_options_attr(
     tcx: TyCtxt<'_>,
 ) -> (Option<DivergingFallbackBehavior>, Option<DivergingBlockBehavior>) {
-    use DivergingFallbackBehavior::*;
-
     // Error handling is dubious here (unwraps), but that's probably fine for an internal attribute.
     // Just don't write incorrect attributes <3
 
@@ -426,10 +422,10 @@ fn parse_never_type_options_attr(
         if item.has_name(sym::fallback) && fallback.is_none() {
             let mode = item.value_str().unwrap();
             match mode {
-                sym::unit => fallback = Some(FallbackToUnit),
+                sym::unit => fallback = Some(DivergingFallbackBehavior::ToUnit),
-                sym::niko => fallback = Some(FallbackToNiko),
+                sym::niko => fallback = Some(DivergingFallbackBehavior::ContextDependent),
-                sym::never => fallback = Some(FallbackToNever),
+                sym::never => fallback = Some(DivergingFallbackBehavior::ToNever),
-                sym::no => fallback = Some(NoFallback),
+                sym::no => fallback = Some(DivergingFallbackBehavior::NoFallback),
                 _ => {
                     tcx.dcx().span_err(item.span(), format!("unknown never type fallback mode: `{mode}` (supported: `unit`, `niko`, `never` and `no`)"));
                 }