Auto merge of #134628 - estebank:const-default, r=oli-obk

Make `Default` const and add some `const Default` impls

Full list of `impl const Default` types:

- ()
- bool
- char
- std::ascii::Char
- usize
- u8
- u16
- u32
- u64
- u128
- i8
- i16
- i32
- i64
- i128
- f16
- f32
- f64
- f128
- std::marker::PhantomData<T>
- Option<T>
- std::iter::Empty<T>
- std::ptr::Alignment
- &[T]
- &mut [T]
- &str
- &mut str
- String
- Vec<T>

Author: bors

clippy_utils/src/visitors.rs

@@ -1,5 +1,7 @@
+use crate::msrvs::Msrv;
 use crate::ty::needs_ordered_drop;
 use crate::{get_enclosing_block, path_to_local_id};
+use crate::qualify_min_const_fn::is_stable_const_fn;
 use core::ops::ControlFlow;
 use rustc_ast::visit::{VisitorResult, try_visit};
 use rustc_hir::def::{CtorKind, DefKind, Res};
@@ -343,13 +345,13 @@ pub fn is_const_evaluatable<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) ->
                     .cx
                     .qpath_res(p, hir_id)
                     .opt_def_id()
-                    .is_some_and(|id| self.cx.tcx.is_const_fn(id)) => {},
+                    .is_some_and(|id| is_stable_const_fn(self.cx, id, Msrv::default())) => {},
                 ExprKind::MethodCall(..)
                     if self
                         .cx
                         .typeck_results()
                         .type_dependent_def_id(e.hir_id)
-                        .is_some_and(|id| self.cx.tcx.is_const_fn(id)) => {},
+                        .is_some_and(|id| is_stable_const_fn(self.cx, id, Msrv::default())) => {},
                 ExprKind::Binary(_, lhs, rhs)
                     if self.cx.typeck_results().expr_ty(lhs).peel_refs().is_primitive_ty()
                         && self.cx.typeck_results().expr_ty(rhs).peel_refs().is_primitive_ty() => {},