Apply suggestions from code review

Code style issues.

Co-authored-by: Eduardo Broto <[email protected]>

clippy_lints/src/field_reassign_with_default.rs

@@ -3,7 +3,7 @@ use if_chain::if_chain;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::Res;
 use rustc_hir::{Block, Expr, ExprKind, PatKind, QPath, Stmt, StmtKind};
-use rustc_middle::ty::{self, Adt, TyS};
+use rustc_middle::ty::{self, Adt, Ty};
 use rustc_span::symbol::{Ident, Symbol};
 
 use rustc_lint::{LateContext, LateLintPass};
@@ -44,7 +44,7 @@ impl LateLintPass<'_> for FieldReassignWithDefault {
         // find all binding statements like `let mut _ = T::default()` where `T::default()` is the
         // `default` method of the `Default` trait, and store statement index in current block being
         // checked and the name of the bound variable
-        let binding_statements_using_default: Vec<(usize, Symbol, &TyS<'_>)> =
+        let binding_statements_using_default =
             enumerate_bindings_using_default(cx, block);
 
         // start from the `let mut _ = _::default();` and look at all the following
@@ -94,7 +94,7 @@ impl LateLintPass<'_> for FieldReassignWithDefault {
 
                 if let StmtKind::Local(preceding_local) = &stmt.kind {
                     // if all fields of the struct are not assigned, add `.. Default::default()` to the suggestion.
-                    let ext_with_default = !fields_of_type(&binding_type)
+                    let ext_with_default = !fields_of_type(binding_type)
                         .iter()
                         .all(|field| assigned_fields.contains_key(&field.name));
 
@@ -114,7 +114,7 @@ impl LateLintPass<'_> for FieldReassignWithDefault {
                     span_lint_and_note(
                         cx,
                         FIELD_REASSIGN_WITH_DEFAULT,
-                        first_assign.unwrap_or_else(|| unreachable!()).span,
+                        first_assign.unwrap().span,
                         "field assignment outside of initializer for an instance created with Default::default()",
                         Some(preceding_local.span),
                         &format!("consider initializing the variable with `{}`", sugg),
@@ -127,10 +127,7 @@ impl LateLintPass<'_> for FieldReassignWithDefault {
 
 /// Returns the block indices, identifiers and types of bindings set as `Default::default()`, except
 /// for when the pattern type is a tuple.
-fn enumerate_bindings_using_default<'cx, 'hir>(
-    cx: &LateContext<'cx>,
-    block: &Block<'hir>,
-) -> Vec<(usize, Symbol, &'cx TyS<'cx>)> {
+fn enumerate_bindings_using_default<'tcx>(cx: &LateContext<'tcx>, block: &Block<'_>) -> Vec<(usize, Symbol, Ty<'tcx>)> {
     block
         .stmts
         .iter()
@@ -141,6 +138,9 @@ fn enumerate_bindings_using_default<'cx, 'hir>(
                 if let StmtKind::Local(ref local) = stmt.kind;
                 // only take bindings to identifiers
                 if let PatKind::Binding(_, _, ident, _) = local.pat.kind;
+                // that are not tuples
+                let ty = cx.typeck_results().pat_ty(local.pat);
+                if !matches!(ty.kind(), ty::Tuple(_));
                 // only when assigning `... = Default::default()`
                 if let Some(ref expr) = local.init;
                 if let ExprKind::Call(ref fn_expr, _) = &expr.kind;
@@ -149,12 +149,6 @@ fn enumerate_bindings_using_default<'cx, 'hir>(
                 // right hand side of assignment is `Default::default`
                 if match_def_path(cx, def_id, &paths::DEFAULT_TRAIT_METHOD);
                 then {
-                    // Get the type of the pattern
-                    let ty = cx.typeck_results().pat_ty(local.pat);
-                    // Ignore tuples
-                    if let ty::Tuple(_) = ty.kind() {
-                        return None;
-                    }
                     Some((idx, ident.name, ty))
                 } else {
                     None
@@ -174,7 +168,7 @@ fn stmt_shadows_binding(this: &Stmt<'_>, shadowed: Symbol) -> bool {
 }
 
 /// Returns the reassigned field and the assigning expression (right-hand side of assign).
-fn field_reassigned_by_stmt<'hir>(this: &Stmt<'hir>, binding_name: Symbol) -> Option<(Ident, &'hir Expr<'hir>)> {
+fn field_reassigned_by_stmt<'tcx>(this: &Stmt<'tcx>, binding_name: Symbol) -> Option<(Ident, &'tcx Expr<'tcx>)> {
     if_chain! {
         // only take assignments
         if let StmtKind::Semi(ref later_expr) = this.kind;
@@ -195,11 +189,11 @@ fn field_reassigned_by_stmt<'hir>(this: &Stmt<'hir>, binding_name: Symbol) -> Op
 }
 
 /// Returns the vec of fields for a struct and an empty vec for non-struct ADTs.
-fn fields_of_type<'a>(ty: &'a TyS<'_>) -> Vec<Ident> {
+fn fields_of_type(ty: Ty<'_>) -> Vec<Ident> {
     if let Adt(adt, _) = ty.kind() {
         if adt.is_struct() {
             // unwrap is safe, because this is a struct and structs have only one variant
-            let variant = &adt.variants.get(0_usize.into()).unwrap();
+            let variant = &adt.non_enum_variant();
             return variant.fields.iter().map(|f| f.ident).collect();
         }
     }