Use std_or_core instead of doing check by hand every time

Author: GuillaumeGomez

clippy_lints/src/default_instead_of_iter_empty.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_with_context;
-use clippy_utils::{is_no_std_crate, last_path_segment};
+use clippy_utils::{last_path_segment, std_or_core};
 use rustc_errors::Applicability;
 use rustc_hir::{def, Expr, ExprKind, GenericArg, QPath, TyKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -42,12 +42,9 @@ impl<'tcx> LateLintPass<'tcx> for DefaultIterEmpty {
             && ty.span.ctxt() == ctxt
         {
             let mut applicability = Applicability::MachineApplicable;
-            let path = if is_no_std_crate(cx) {
-                "core::iter::empty"
-            } else {
-                "std::iter::empty"
-            };
-            let sugg = make_sugg(cx, ty_path, ctxt, &mut applicability, path);
+            let Some(path) = std_or_core(cx) else { return };
+            let path = format!("{path}::iter::empty");
+            let sugg = make_sugg(cx, ty_path, ctxt, &mut applicability, &path);
             span_lint_and_sugg(
                 cx,
                 DEFAULT_INSTEAD_OF_ITER_EMPTY,

clippy_lints/src/mem_replace.rs

@@ -3,7 +3,7 @@ use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg, span_lin
 use clippy_utils::source::{snippet, snippet_with_applicability};
 use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::is_non_aggregate_primitive_type;
-use clippy_utils::{is_default_equivalent, is_no_std_crate, is_res_lang_ctor, path_res, peel_ref_operators};
+use clippy_utils::{is_default_equivalent, is_res_lang_ctor, path_res, peel_ref_operators, std_or_core};
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::OptionNone;
 use rustc_hir::{Expr, ExprKind};
@@ -123,15 +123,12 @@ fn check_replace_option_with_none(cx: &LateContext<'_>, dest: &Expr<'_>, expr_sp
     );
 }
 
-fn get_top_crate(cx: &LateContext<'_>) -> &'static str {
-    if is_no_std_crate(cx) { "core" } else { "std" }
-}
-
 fn check_replace_with_uninit(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<'_>, expr_span: Span) {
     if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(src.hir_id)
         // check if replacement is mem::MaybeUninit::uninit().assume_init()
         && cx.tcx.is_diagnostic_item(sym::assume_init, method_def_id)
     {
+        let Some(top_crate) = std_or_core(cx) else { return };
         let mut applicability = Applicability::MachineApplicable;
         span_lint_and_sugg(
             cx,
@@ -140,8 +137,7 @@ fn check_replace_with_uninit(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<'
             "replacing with `mem::MaybeUninit::uninit().assume_init()`",
             "consider using",
             format!(
-                "{}::ptr::read({})",
-                get_top_crate(cx),
+                "{top_crate}::ptr::read({})",
                 snippet_with_applicability(cx, dest.span, "", &mut applicability)
             ),
             applicability,
@@ -154,6 +150,7 @@ fn check_replace_with_uninit(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<'
         && let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id()
     {
         if cx.tcx.is_diagnostic_item(sym::mem_uninitialized, repl_def_id) {
+            let Some(top_crate) = std_or_core(cx) else { return };
             let mut applicability = Applicability::MachineApplicable;
             span_lint_and_sugg(
                 cx,
@@ -162,8 +159,7 @@ fn check_replace_with_uninit(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<'
                 "replacing with `mem::uninitialized()`",
                 "consider using",
                 format!(
-                    "{}::ptr::read({})",
-                    get_top_crate(cx),
+                    "{top_crate}::ptr::read({})",
                     snippet_with_applicability(cx, dest.span, "", &mut applicability)
                 ),
                 applicability,
@@ -190,7 +186,7 @@ fn check_replace_with_default(cx: &LateContext<'_>, src: &Expr<'_>, dest: &Expr<
         return;
     }
     if is_default_equivalent(cx, src) && !in_external_macro(cx.tcx.sess, expr_span) {
-        let top_crate = get_top_crate(cx);
+        let Some(top_crate) = std_or_core(cx) else { return };
         span_lint_and_then(
             cx,
             MEM_REPLACE_WITH_DEFAULT,

clippy_lints/src/methods/iter_on_single_or_empty_collections.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet;
-use clippy_utils::{get_expr_use_or_unification_node, is_no_std_crate, is_res_lang_ctor, path_res};
+use clippy_utils::{get_expr_use_or_unification_node, is_res_lang_ctor, path_res, std_or_core};
 
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
@@ -58,7 +58,7 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, method_name: &str, re
         return;
     }
 
-    let top_crate = if is_no_std_crate(cx) { "core" } else { "std" };
+    let Some(top_crate) = std_or_core(cx) else { return };
     if let Some(i) = item {
         let sugg = format!(
             "{top_crate}::iter::once({}{})",

clippy_lints/src/operators/ptr_eq.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::is_no_std_crate;
 use clippy_utils::source::snippet_opt;
+use clippy_utils::std_or_core;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::LateContext;
@@ -25,7 +25,7 @@ pub(super) fn check<'tcx>(
             && let Some(left_snip) = snippet_opt(cx, left_var.span)
             && let Some(right_snip) = snippet_opt(cx, right_var.span)
         {
-            let top_crate = if is_no_std_crate(cx) { "core" } else { "std" };
+            let Some(top_crate) = std_or_core(cx) else { return };
             span_lint_and_sugg(
                 cx,
                 PTR_EQ,

clippy_lints/src/transmute/transmute_int_to_char.rs

@@ -1,6 +1,6 @@
 use super::TRANSMUTE_INT_TO_CHAR;
 use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::{is_no_std_crate, sugg};
+use clippy_utils::{std_or_core, sugg};
 use rustc_ast as ast;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
@@ -25,6 +25,7 @@ pub(super) fn check<'tcx>(
                 e.span,
                 &format!("transmute from a `{from_ty}` to a `char`"),
                 |diag| {
+                    let Some(top_crate) = std_or_core(cx) else { return };
                     let arg = sugg::Sugg::hir(cx, arg, "..");
                     let arg = if let ty::Int(_) = from_ty.kind() {
                         arg.as_ty(ast::UintTy::U32.name_str())
@@ -34,10 +35,7 @@ pub(super) fn check<'tcx>(
                     diag.span_suggestion(
                         e.span,
                         "consider using",
-                        format!(
-                            "{}::char::from_u32({arg}).unwrap()",
-                            if is_no_std_crate(cx) { "core" } else { "std" }
-                        ),
+                        format!("{top_crate}::char::from_u32({arg}).unwrap()"),
                         Applicability::Unspecified,
                     );
                 },

clippy_lints/src/transmute/transmute_ref_to_ref.rs

@@ -1,7 +1,7 @@
 use super::{TRANSMUTE_BYTES_TO_STR, TRANSMUTE_PTR_TO_PTR};
 use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::source::snippet;
-use clippy_utils::{is_no_std_crate, sugg};
+use clippy_utils::{std_or_core, sugg};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, Mutability};
 use rustc_lint::LateContext;
@@ -25,12 +25,12 @@ pub(super) fn check<'tcx>(
             && let ty::Uint(ty::UintTy::U8) = slice_ty.kind()
             && from_mutbl == to_mutbl
         {
+            let Some(top_crate) = std_or_core(cx) else { return true };
+
             let postfix = if *from_mutbl == Mutability::Mut { "_mut" } else { "" };
 
             let snippet = snippet(cx, arg.span, "..");
 
-            let top_crate = if is_no_std_crate(cx) { "core" } else { "std" };
-
             span_lint_and_sugg(
                 cx,
                 TRANSMUTE_BYTES_TO_STR,