Avoid passing a full Pat when only the Span/HirId is used

Author: oli-obk

compiler/rustc_hir_typeck/src/pat.rs

@@ -254,7 +254,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.check_pat_tuple_struct(pat, qpath, subpats, ddpos, expected, pat_info)
             }
             PatKind::Path(ref qpath) => {
-                self.check_pat_path(pat, qpath, path_res.unwrap(), expected, ti)
+                self.check_pat_path(pat.hir_id, pat.span, qpath, path_res.unwrap(), expected, ti)
             }
             PatKind::Struct(ref qpath, fields, has_rest_pat) => {
                 self.check_pat_struct(pat, qpath, fields, has_rest_pat, expected, pat_info)
@@ -1020,7 +1020,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
     fn check_pat_path(
         &self,
-        pat: &Pat<'tcx>,
+        hir_id: HirId,
+        span: Span,
         qpath: &hir::QPath<'_>,
         path_resolution: (Res, Option<LoweredTy<'tcx>>, &'tcx [hir::PathSegment<'tcx>]),
         expected: Ty<'tcx>,
@@ -1039,8 +1040,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             Res::Def(DefKind::AssocFn | DefKind::Ctor(_, CtorKind::Fn) | DefKind::Variant, _) => {
                 let expected = "unit struct, unit variant or constant";
-                let e =
-                    report_unexpected_variant_res(tcx, res, None, qpath, pat.span, E0533, expected);
+                let e = report_unexpected_variant_res(tcx, res, None, qpath, span, E0533, expected);
                 return Ty::new_error(tcx, e);
             }
             Res::SelfCtor(def_id) => {
@@ -1055,7 +1055,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         res,
                         None,
                         qpath,
-                        pat.span,
+                        span,
                         E0533,
                         "unit struct",
                     );
@@ -1074,11 +1074,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         // Type-check the path.
         let (pat_ty, pat_res) =
-            self.instantiate_value_path(segments, opt_ty, res, pat.span, pat.span, pat.hir_id);
+            self.instantiate_value_path(segments, opt_ty, res, span, span, hir_id);
         if let Err(err) =
-            self.demand_suptype_with_origin(&self.pattern_cause(ti, pat.span), expected, pat_ty)
+            self.demand_suptype_with_origin(&self.pattern_cause(ti, span), expected, pat_ty)
         {
-            self.emit_bad_pat_path(err, pat, res, pat_res, pat_ty, segments);
+            self.emit_bad_pat_path(err, hir_id, span, res, pat_res, pat_ty, segments);
         }
         pat_ty
     }
@@ -1121,13 +1121,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     fn emit_bad_pat_path(
         &self,
         mut e: Diag<'_>,
-        pat: &hir::Pat<'tcx>,
+        hir_id: HirId,
+        pat_span: Span,
         res: Res,
         pat_res: Res,
         pat_ty: Ty<'tcx>,
         segments: &'tcx [hir::PathSegment<'tcx>],
     ) {
-        let pat_span = pat.span;
         if let Some(span) = self.tcx.hir().res_span(pat_res) {
             e.span_label(span, format!("{} defined here", res.descr()));
             if let [hir::PathSegment { ident, .. }] = &*segments {
@@ -1140,7 +1140,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         res.descr(),
                     ),
                 );
-                match self.tcx.parent_hir_node(pat.hir_id) {
+                match self.tcx.parent_hir_node(hir_id) {
                     hir::Node::PatField(..) => {
                         e.span_suggestion_verbose(
                             ident.span.shrink_to_hi(),