Use if let instead of match when only matching a single variant (clippy::single_match)

Makes code more compact and reduces nestig.

3 files changed, 30 insertions, 36 deletions

diff --git a/src/librustc_mir/dataflow/framework/graphviz.rs b/src/librustc_mir/dataflow/framework/graphviz.rs
index a85c428d3bf..bdd41121359 100644
--- a/src/librustc_mir/dataflow/framework/graphviz.rs
+++ b/src/librustc_mir/dataflow/framework/graphviz.rs
@@ -229,26 +229,22 @@ where
         }
 
         // Write any changes caused by terminator-specific effects
-        match terminator.kind {
-            mir::TerminatorKind::Call { destination: Some(_), .. } => {
-                let num_state_columns = self.num_state_columns();
-                self.write_row(w, "", "(on successful return)", |this, w, fmt| {
-                    write!(
-                        w,
-                        r#"<td balign="left" colspan="{colspan}" {fmt} align="left">"#,
-                        colspan = num_state_columns,
-                        fmt = fmt,
-                    )?;
-
-                    let state_on_unwind = this.results.get().clone();
-                    this.results.seek_after_assume_success(terminator_loc);
-                    write_diff(w, this.results.analysis(), &state_on_unwind, this.results.get())?;
-
-                    write!(w, "</td>")
-                })?;
-            }
-
-            _ => {}
+        if let mir::TerminatorKind::Call { destination: Some(_), .. } = terminator.kind {
+            let num_state_columns = self.num_state_columns();
+            self.write_row(w, "", "(on successful return)", |this, w, fmt| {
+                write!(
+                    w,
+                    r#"<td balign="left" colspan="{colspan}" {fmt} align="left">"#,
+                    colspan = num_state_columns,
+                    fmt = fmt,
+                )?;
+
+                let state_on_unwind = this.results.get().clone();
+                this.results.seek_after_assume_success(terminator_loc);
+                write_diff(w, this.results.analysis(), &state_on_unwind, this.results.get())?;
+
+                write!(w, "</td>")
+            })?;
         };
 
         write!(w, "</table>")
diff --git a/src/librustc_mir/dataflow/impls/mod.rs b/src/librustc_mir/dataflow/impls/mod.rs
index 3572d460274..3ffa771cb05 100644
--- a/src/librustc_mir/dataflow/impls/mod.rs
+++ b/src/librustc_mir/dataflow/impls/mod.rs
@@ -544,18 +544,15 @@ impl<'tcx> GenKillAnalysis<'tcx> for EverInitializedPlaces<'_, 'tcx> {
         );
         trans.gen_all(init_loc_map[location].iter().copied());
 
-        match stmt.kind {
-            mir::StatementKind::StorageDead(local) => {
-                // End inits for StorageDead, so that an immutable variable can
-                // be reinitialized on the next iteration of the loop.
-                let move_path_index = rev_lookup.find_local(local);
-                debug!(
-                    "stmt {:?} at loc {:?} clears the ever initialized status of {:?}",
-                    stmt, location, &init_path_map[move_path_index]
-                );
-                trans.kill_all(init_path_map[move_path_index].iter().copied());
-            }
-            _ => {}
+        if let mir::StatementKind::StorageDead(local) = stmt.kind {
+            // End inits for StorageDead, so that an immutable variable can
+            // be reinitialized on the next iteration of the loop.
+            let move_path_index = rev_lookup.find_local(local);
+            debug!(
+                "stmt {:?} at loc {:?} clears the ever initialized status of {:?}",
+                stmt, location, &init_path_map[move_path_index]
+            );
+            trans.kill_all(init_path_map[move_path_index].iter().copied());
         }
     }
 
diff --git a/src/librustc_mir/dataflow/move_paths/builder.rs b/src/librustc_mir/dataflow/move_paths/builder.rs
index 6918d165a2b..1f4455318a4 100644
--- a/src/librustc_mir/dataflow/move_paths/builder.rs
+++ b/src/librustc_mir/dataflow/move_paths/builder.rs
@@ -144,15 +144,16 @@ impl<'b, 'a, 'tcx> Gatherer<'b, 'a, 'tcx> {
                         },
                     ));
                 }
-                ty::Array(..) => match elem {
-                    ProjectionElem::Index(..) => {
+
+                ty::Array(..) => {
+                    if let ProjectionElem::Index(..) = elem {
                         return Err(MoveError::cannot_move_out_of(
                             self.loc,
                             InteriorOfSliceOrArray { ty: place_ty, is_index: true },
                         ));
                     }
-                    _ => {}
-                },
+                }
+
                 _ => {}
             };