Remove span from hir::Arm.

Author: cjgillot

compiler/rustc_ast_lowering/src/expr.rs

@@ -520,7 +520,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
             pat,
             guard,
             body: self.lower_expr(&arm.body),
-            span: arm.span,
         }
     }
 
@@ -2054,13 +2053,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
     }
 
     fn arm(&mut self, pat: &'hir hir::Pat<'hir>, expr: &'hir hir::Expr<'hir>) -> hir::Arm<'hir> {
-        hir::Arm {
-            hir_id: self.next_id(expr.span),
-            attrs: &[],
-            pat,
-            guard: None,
-            span: expr.span,
-            body: expr,
-        }
+        hir::Arm { hir_id: self.next_id(expr.span), attrs: &[], pat, guard: None, body: expr }
     }
 }

compiler/rustc_hir/src/hir.rs

@@ -1149,7 +1149,6 @@ pub struct Local<'hir> {
 pub struct Arm<'hir> {
     #[stable_hasher(ignore)]
     pub hir_id: HirId,
-    pub span: Span,
     pub attrs: &'hir [Attribute],
     /// If this pattern and the optional guard matches, then `body` is evaluated.
     pub pat: &'hir Pat<'hir>,

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -783,7 +783,7 @@ fn convert_arm<'tcx>(cx: &mut Cx<'_, 'tcx>, arm: &'tcx hir::Arm<'tcx>) -> Arm<'t
         body: arm.body.to_ref(),
         lint_level: LintLevel::Explicit(arm.hir_id),
         scope: region::Scope { id: arm.hir_id.local_id, data: region::ScopeData::Node },
-        span: arm.span,
+        span: cx.tcx.hir().span(arm.hir_id),
     }
 }