Auto merge of rust-lang#10153 - llogiq:box-default-trim-paths, r=Jarcho

trim paths in `box_default`

This might help with rust-lang#10089, though I have not tested that yet. In any event, it keeps the suggestion short and to the point.

---
changelog: Trim paths in [`box_default`] suggestion

Author: bors

clippy_lints/src/box_default.rs

@@ -8,7 +8,7 @@ use rustc_hir::{
     Block, Expr, ExprKind, Local, Node, QPath, TyKind,
 };
 use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::lint::in_external_macro;
+use rustc_middle::{lint::in_external_macro, ty::print::with_forced_trimmed_paths};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
@@ -59,7 +59,7 @@ impl LateLintPass<'_> for BoxDefault {
                 if is_plain_default(arg_path) || given_type(cx, expr) {
                     "Box::default()".into()
                 } else {
-                    format!("Box::<{arg_ty}>::default()")
+                    with_forced_trimmed_paths!(format!("Box::<{arg_ty}>::default()"))
                 },
                 Applicability::MachineApplicable
             );

tests/ui/box_default.fixed

@@ -21,16 +21,16 @@ macro_rules! outer {
 fn main() {
     let _string: Box<String> = Box::default();
     let _byte = Box::<u8>::default();
-    let _vec = Box::<std::vec::Vec<u8>>::default();
+    let _vec = Box::<Vec<u8>>::default();
     let _impl = Box::<ImplementsDefault>::default();
     let _impl2 = Box::<ImplementsDefault>::default();
     let _impl3: Box<ImplementsDefault> = Box::default();
     let _own = Box::new(OwnDefault::default()); // should not lint
-    let _in_macro = outer!(Box::<std::string::String>::default());
-    let _string_default = outer!(Box::<std::string::String>::default());
+    let _in_macro = outer!(Box::<String>::default());
+    let _string_default = outer!(Box::<String>::default());
     let _vec2: Box<Vec<ImplementsDefault>> = Box::default();
     let _vec3: Box<Vec<bool>> = Box::default();
-    let _vec4: Box<_> = Box::<std::vec::Vec<bool>>::default();
+    let _vec4: Box<_> = Box::<Vec<bool>>::default();
     let _more = ret_ty_fn();
     call_ty_fn(Box::default());
 }

tests/ui/box_default.stderr

@@ -16,7 +16,7 @@ error: `Box::new(_)` of default value
   --> $DIR/box_default.rs:24:16
    |
 LL |     let _vec = Box::new(Vec::<u8>::new());
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<std::vec::Vec<u8>>::default()`
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<Vec<u8>>::default()`
 
 error: `Box::new(_)` of default value
   --> $DIR/box_default.rs:25:17
@@ -40,13 +40,13 @@ error: `Box::new(_)` of default value
   --> $DIR/box_default.rs:29:28
    |
 LL |     let _in_macro = outer!(Box::new(String::new()));
-   |                            ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<std::string::String>::default()`
+   |                            ^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<String>::default()`
 
 error: `Box::new(_)` of default value
   --> $DIR/box_default.rs:30:34
    |
 LL |     let _string_default = outer!(Box::new(String::from("")));
-   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<std::string::String>::default()`
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<String>::default()`
 
 error: `Box::new(_)` of default value
   --> $DIR/box_default.rs:31:46
@@ -64,7 +64,7 @@ error: `Box::new(_)` of default value
   --> $DIR/box_default.rs:33:25
    |
 LL |     let _vec4: Box<_> = Box::new(Vec::from([false; 0]));
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<std::vec::Vec<bool>>::default()`
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Box::<Vec<bool>>::default()`
 
 error: `Box::new(_)` of default value
   --> $DIR/box_default.rs:35:16