Rustup (#14080)

r? @ghost

changelog: none

Author: flip1995

.github/driver.sh

@@ -47,9 +47,9 @@ unset CARGO_MANIFEST_DIR
 
 # Run a lint and make sure it produces the expected output. It's also expected to exit with code 1
 # FIXME: How to match the clippy invocation in compile-test.rs?
-./target/debug/clippy-driver -Dwarnings -Aunused -Zui-testing --emit metadata --crate-type bin tests/ui/double_neg.rs 2>double_neg.stderr && exit 1
-sed -e "/= help: for/d" double_neg.stderr > normalized.stderr
-diff -u normalized.stderr tests/ui/double_neg.stderr
+./target/debug/clippy-driver -Dwarnings -Aunused -Zui-testing --emit metadata --crate-type bin tests/ui/string_to_string.rs 2>string_to_string.stderr && exit 1
+sed -e "/= help: for/d" string_to_string.stderr > normalized.stderr
+diff -u normalized.stderr tests/ui/string_to_string.stderr
 
 # make sure "clippy-driver --rustc --arg" and "rustc --arg" behave the same
 SYSROOT=$(rustc --print sysroot)

book/src/usage.md

@@ -33,7 +33,7 @@ You can configure lint levels on the command line by adding
 `-A/W/D clippy::lint_name` like this:
 
 ```bash
-cargo clippy -- -Aclippy::style -Wclippy::double_neg -Dclippy::perf
+cargo clippy -- -Aclippy::style -Wclippy::box_default -Dclippy::perf
 ```
 
 For [CI] all warnings can be elevated to errors which will in turn fail
@@ -101,11 +101,10 @@ You can configure lint levels in source code the same way you can configure
 ```rust,ignore
 #![allow(clippy::style)]
 
-#[warn(clippy::double_neg)]
+#[warn(clippy::box_default)]
 fn main() {
-    let x = 1;
-    let y = --x;
-    //      ^^ warning: double negation
+    let _ = Box::<String>::new(Default::default());
+    // ^ warning: `Box::new(_)` of default value
 }
 ```
 

clippy_lints/src/box_default.rs

@@ -4,12 +4,12 @@ use clippy_utils::ty::expr_sig;
 use clippy_utils::{is_default_equivalent, path_def_id};
 use rustc_errors::Applicability;
 use rustc_hir::def::Res;
-use rustc_hir::intravisit::{Visitor, walk_ty};
-use rustc_hir::{Block, Expr, ExprKind, LetStmt, Node, QPath, Ty, TyKind};
+use rustc_hir::intravisit::{InferKind, Visitor, VisitorExt, walk_ty};
+use rustc_hir::{AmbigArg, Block, Expr, ExprKind, HirId, LetStmt, Node, QPath, Ty, TyKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
-use rustc_span::sym;
+use rustc_span::{Span, sym};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -92,8 +92,13 @@ fn is_local_vec_expn(cx: &LateContext<'_>, expr: &Expr<'_>, ref_expr: &Expr<'_>)
 struct InferVisitor(bool);
 
 impl Visitor<'_> for InferVisitor {
-    fn visit_ty(&mut self, t: &Ty<'_>) {
-        self.0 |= matches!(t.kind, TyKind::Infer | TyKind::OpaqueDef(..) | TyKind::TraitObject(..));
+    fn visit_infer(&mut self, inf_id: HirId, _inf_span: Span, _kind: InferKind<'_>) -> Self::Result {
+        self.0 = true;
+        self.visit_id(inf_id);
+    }
+
+    fn visit_ty(&mut self, t: &Ty<'_, AmbigArg>) {
+        self.0 |= matches!(t.kind, TyKind::OpaqueDef(..) | TyKind::TraitObject(..));
         if !self.0 {
             walk_ty(self, t);
         }
@@ -104,7 +109,7 @@ fn given_type(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     match cx.tcx.parent_hir_node(expr.hir_id) {
         Node::LetStmt(LetStmt { ty: Some(ty), .. }) => {
             let mut v = InferVisitor::default();
-            v.visit_ty(ty);
+            v.visit_ty_unambig(ty);
             !v.0
         },
         Node::Expr(Expr {

clippy_lints/src/casts/as_pointer_underscore.rs

@@ -4,7 +4,7 @@ use rustc_middle::ty::Ty;
 
 pub fn check<'tcx>(cx: &LateContext<'tcx>, ty_into: Ty<'_>, cast_to_hir: &'tcx rustc_hir::Ty<'tcx>) {
     if let rustc_hir::TyKind::Ptr(rustc_hir::MutTy { ty, .. }) = cast_to_hir.kind
-        && matches!(ty.kind, rustc_hir::TyKind::Infer)
+        && matches!(ty.kind, rustc_hir::TyKind::Infer(()))
     {
         clippy_utils::diagnostics::span_lint_and_sugg(
             cx,

clippy_lints/src/casts/as_underscore.rs

@@ -7,7 +7,7 @@ use rustc_middle::ty;
 use super::AS_UNDERSCORE;
 
 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, ty: &'tcx Ty<'_>) {
-    if matches!(ty.kind, TyKind::Infer) {
+    if matches!(ty.kind, TyKind::Infer(())) {
         span_lint_and_then(cx, AS_UNDERSCORE, expr.span, "using `as _` conversion", |diag| {
             let ty_resolved = cx.typeck_results().expr_ty(expr);
             if let ty::Error(_) = ty_resolved.kind() {

clippy_lints/src/casts/cast_lossless.rs

@@ -38,7 +38,7 @@ pub(super) fn check(
                 return;
             };
             match cast_to_hir.kind {
-                TyKind::Infer => {
+                TyKind::Infer(()) => {
                     diag.span_suggestion_verbose(
                         expr.span,
                         "use `Into::into` instead",

clippy_lints/src/casts/cast_ptr_alignment.rs

@@ -24,7 +24,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
             && let Some(generic_args) = method_path.args
             && let [GenericArg::Type(cast_to)] = generic_args.args
             // There probably is no obvious reason to do this, just to be consistent with `as` cases.
-            && !is_hir_ty_cfg_dependant(cx, cast_to)
+            && !is_hir_ty_cfg_dependant(cx, cast_to.as_unambig_ty())
         {
             let (cast_from, cast_to) = (cx.typeck_results().expr_ty(self_arg), cx.typeck_results().expr_ty(expr));
             lint_cast_ptr_alignment(cx, expr, cast_from, cast_to);

clippy_lints/src/casts/ptr_as_ptr.rs

@@ -43,9 +43,9 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, msrv: &Msrv) {
     {
         let mut app = Applicability::MachineApplicable;
         let turbofish = match &cast_to_hir_ty.kind {
-            TyKind::Infer => String::new(),
+            TyKind::Infer(()) => String::new(),
             TyKind::Ptr(mut_ty) => {
-                if matches!(mut_ty.ty.kind, TyKind::Infer) {
+                if matches!(mut_ty.ty.kind, TyKind::Infer(())) {
                     String::new()
                 } else {
                     format!(

clippy_lints/src/casts/ref_as_ptr.rs

@@ -34,9 +34,9 @@ pub(super) fn check<'tcx>(
 
         let mut app = Applicability::MachineApplicable;
         let turbofish = match &cast_to_hir_ty.kind {
-            TyKind::Infer => String::new(),
+            TyKind::Infer(()) => String::new(),
             TyKind::Ptr(mut_ty) => {
-                if matches!(mut_ty.ty.kind, TyKind::Infer) {
+                if matches!(mut_ty.ty.kind, TyKind::Infer(())) {
                     String::new()
                 } else {
                     format!(

clippy_lints/src/casts/unnecessary_cast.rs

@@ -43,7 +43,7 @@ pub(super) fn check<'tcx>(
                 }
             },
             // Ignore `p as *const _`
-            TyKind::Infer => return false,
+            TyKind::Infer(()) => return false,
             _ => {},
         }