Auto merge of #132251 - jieyouxu:rollup-mtv9mpd, r=jieyouxu

Rollup of 7 pull requests

Successful merges:

 - #131633 (error on alignments greater than `isize::MAX`)
 - #132086 (Tweak E0277 highlighting and "long type" path printing)
 - #132220 (Add GUI regression test for doc struct fields margins)
 - #132225 (Dynamically link run-make support)
 - #132227 (Pass constness with span into lower_poly_trait_ref)
 - #132242 (Support `char::is_digit` in const contexts.)
 - #132243 (Remove `ObligationCause::span()` method)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 8 insertions, 11 deletions

diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index 8ee8b4c4823..40e5ec45959 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -92,16 +92,6 @@ impl<'tcx> ObligationCause<'tcx> {
         ObligationCause { span, body_id: CRATE_DEF_ID, code: Default::default() }
     }
 
-    pub fn span(&self) -> Span {
-        match *self.code() {
-            ObligationCauseCode::MatchExpressionArm(box MatchExpressionArmCause {
-                arm_span,
-                ..
-            }) => arm_span,
-            _ => self.span,
-        }
-    }
-
     #[inline]
     pub fn code(&self) -> &ObligationCauseCode<'tcx> {
         &self.code
@@ -517,10 +507,17 @@ pub struct MatchExpressionArmCause<'tcx> {
     pub prior_arm_block_id: Option<HirId>,
     pub prior_arm_ty: Ty<'tcx>,
     pub prior_arm_span: Span,
+    /// Span of the scrutinee of the match (the matched value).
     pub scrut_span: Span,
+    /// Source of the match, i.e. `match` or a desugaring.
     pub source: hir::MatchSource,
+    /// Span of the *whole* match expr.
+    pub expr_span: Span,
+    /// Spans of the previous arms except for those that diverge (i.e. evaluate to `!`).
+    ///
+    /// These are used for pointing out errors that may affect several arms.
     pub prior_non_diverging_arms: Vec<Span>,
-    // Is the expectation of this match expression an RPIT?
+    /// Is the expectation of this match expression an RPIT?
     pub tail_defines_return_position_impl_trait: Option<LocalDefId>,
 }