Move more def paths into clippy_utils::paths (#13903)

I discovered that there were paths declared in `clippy_utils::paths` in
rust-lang/rust-clippy#13829 so moving a few
remaining hardcoded ones in one place.

changelog: Move more def paths into `clippy_utils::paths`

r? @y21

clippy_lints/src/methods/needless_character_iteration.rs

@@ -7,6 +7,7 @@ use rustc_span::Span;
 use super::NEEDLESS_CHARACTER_ITERATION;
 use super::utils::get_last_chain_binding_hir_id;
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::paths::CHAR_IS_ASCII;
 use clippy_utils::source::SpanRangeExt;
 use clippy_utils::{match_def_path, path_to_local_id, peel_blocks};
 
@@ -77,7 +78,7 @@ fn handle_expr(
             if revert != is_all
                 && let ExprKind::Path(path) = fn_path.kind
                 && let Some(fn_def_id) = cx.qpath_res(&path, fn_path.hir_id).opt_def_id()
-                && match_def_path(cx, fn_def_id, &["core", "char", "methods", "<impl char>", "is_ascii"])
+                && match_def_path(cx, fn_def_id, &CHAR_IS_ASCII)
                 && path_to_local_id(peels_expr_ref(arg), first_param)
                 && let Some(snippet) = before_chars.get_source_text(cx)
             {

clippy_lints/src/methods/read_line_without_trim.rs

@@ -1,6 +1,7 @@
 use std::ops::ControlFlow;
 
 use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::paths::STDIN;
 use clippy_utils::source::snippet;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::visitors::for_each_local_use_after_expr;
@@ -33,7 +34,7 @@ fn parse_fails_on_trailing_newline(ty: Ty<'_>) -> bool {
 
 pub fn check(cx: &LateContext<'_>, call: &Expr<'_>, recv: &Expr<'_>, arg: &Expr<'_>) {
     if let Some(recv_adt) = cx.typeck_results().expr_ty(recv).ty_adt_def()
-        && match_def_path(cx, recv_adt.did(), &["std", "io", "stdio", "Stdin"])
+        && match_def_path(cx, recv_adt.did(), &STDIN)
         && let ExprKind::Path(QPath::Resolved(_, path)) = arg.peel_borrows().kind
         && let Res::Local(local_id) = path.res
     {

clippy_lints/src/utils/internal_lints/invalid_paths.rs

@@ -73,6 +73,7 @@ pub fn check_path(cx: &LateContext<'_>, path: &[&str]) -> bool {
         SimplifiedType::Slice,
         SimplifiedType::Str,
         SimplifiedType::Bool,
+        SimplifiedType::Char,
     ]
     .iter()
     .flat_map(|&ty| cx.tcx.incoherent_impls(ty).iter())

clippy_utils/src/paths.rs

@@ -33,6 +33,8 @@ pub const CHILD: [&str; 3] = ["std", "process", "Child"];
 pub const CHILD_ID: [&str; 4] = ["std", "process", "Child", "id"];
 pub const CHILD_KILL: [&str; 4] = ["std", "process", "Child", "kill"];
 pub const PANIC_ANY: [&str; 3] = ["std", "panic", "panic_any"];
+pub const CHAR_IS_ASCII: [&str; 5] = ["core", "char", "methods", "<impl char>", "is_ascii"];
+pub const STDIN: [&str; 4] = ["std", "io", "stdio", "Stdin"];
 
 // Paths in clippy itself
 pub const MSRV: [&str; 3] = ["clippy_utils", "msrvs", "Msrv"];