diff options
| -rw-r--r-- | compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs index afba812a8e7..2a2c4ac10b2 100644 --- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs +++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs @@ -124,7 +124,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { body_id: LocalDefId, ) -> FnCtxt<'a, 'tcx> { let (diverging_fallback_behavior, diverging_block_behavior) = - parse_never_type_options_attr(root_ctxt.tcx); + never_type_behavior(root_ctxt.tcx); FnCtxt { body_id, param_env, @@ -380,9 +380,30 @@ impl<'tcx> LoweredTy<'tcx> { } } +fn never_type_behavior(tcx: TyCtxt<'_>) -> (DivergingFallbackBehavior, DivergingBlockBehavior) { + let (fallback, block) = parse_never_type_options_attr(tcx); + let fallback = fallback.unwrap_or_else(|| default_fallback(tcx)); + let block = block.unwrap_or_default(); + + (fallback, block) +} + +/// 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::*; + + // `feature(never_type_fallback)`: fallback to `!` or `()` trying to not break stuff + if tcx.features().never_type_fallback { + return FallbackToNiko; + } + + // Otherwise: fallback to `()` + FallbackToUnit +} + fn parse_never_type_options_attr( tcx: TyCtxt<'_>, -) -> (DivergingFallbackBehavior, DivergingBlockBehavior) { +) -> (Option<DivergingFallbackBehavior>, Option<DivergingBlockBehavior>) { use DivergingFallbackBehavior::*; // Error handling is dubious here (unwraps), but that's probably fine for an internal attribute. @@ -432,11 +453,5 @@ fn parse_never_type_options_attr( ); } - let fallback = fallback.unwrap_or_else(|| { - if tcx.features().never_type_fallback { FallbackToNiko } else { FallbackToUnit } - }); - - let block = block.unwrap_or_default(); - (fallback, block) } |