Replace some Symbol::as_str usage (#14679)

Follow up to https://github.com/rust-lang/rust-clippy/pull/14650

Replaces uses in the form `s.as_str() == "literal"`

r? @y21

changelog: none

clippy_utils/src/higher.rs

@@ -3,14 +3,14 @@
 #![deny(clippy::missing_docs_in_private_items)]
 
 use crate::consts::{ConstEvalCtxt, Constant};
-use crate::is_expn_of;
 use crate::ty::is_type_diagnostic_item;
+use crate::{is_expn_of, sym};
 
 use rustc_ast::ast;
 use rustc_hir as hir;
 use rustc_hir::{Arm, Block, Expr, ExprKind, HirId, LoopSource, MatchSource, Node, Pat, QPath, StructTailExpr};
 use rustc_lint::LateContext;
-use rustc_span::{Span, sym, symbol};
+use rustc_span::{Span, symbol};
 
 /// The essential nodes of a desugared for loop as well as the entire span:
 /// `for pat in arg { body }` becomes `(pat, arg, body)`. Returns `(pat, arg, body, span)`.
@@ -474,7 +474,7 @@ pub fn get_vec_init_kind<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -
                     return Some(VecInitKind::New);
                 } else if name.ident.name == symbol::kw::Default {
                     return Some(VecInitKind::Default);
-                } else if name.ident.name.as_str() == "with_capacity" {
+                } else if name.ident.name == sym::with_capacity {
                     let arg = args.first()?;
                     return match ConstEvalCtxt::new(cx).eval_simple(arg) {
                         Some(Constant::Int(num)) => Some(VecInitKind::WithConstCapacity(num)),

clippy_utils/src/lib.rs

@@ -1412,7 +1412,7 @@ pub fn is_in_panic_handler(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
 }
 
 /// Gets the name of the item the expression is in, if available.
-pub fn get_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
+pub fn parent_item_name(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<Symbol> {
     let parent_id = cx.tcx.hir_get_parent_item(expr.hir_id).def_id;
     match cx.tcx.hir_node_by_def_id(parent_id) {
         Node::Item(item) => item.kind.ident().map(|ident| ident.name),
@@ -2088,7 +2088,7 @@ pub fn match_libc_symbol(cx: &LateContext<'_>, did: DefId, name: &str) -> bool {
     let path = cx.get_def_path(did);
     // libc is meant to be used as a flat list of names, but they're all actually defined in different
     // modules based on the target platform. Ignore everything but crate name and the item name.
-    path.first().is_some_and(|s| s.as_str() == "libc") && path.last().is_some_and(|s| s.as_str() == name)
+    path.first().is_some_and(|s| *s == sym::libc) && path.last().is_some_and(|s| s.as_str() == name)
 }
 
 /// Returns the list of condition expressions and the list of blocks in a

clippy_utils/src/sym.rs

@@ -30,33 +30,75 @@ macro_rules! generate {
 }
 
 generate! {
+    abs,
     as_bytes,
     as_deref_mut,
     as_deref,
     as_mut,
     Binary,
+    build_hasher,
+    cargo_clippy: "cargo-clippy",
     Cargo_toml: "Cargo.toml",
+    cast,
+    chars,
     CLIPPY_ARGS,
     CLIPPY_CONF_DIR,
+    clone_into,
     cloned,
+    collect,
     contains,
     copied,
+    CRLF: "\r\n",
     Current,
+    ends_with,
+    exp,
+    extend,
+    finish_non_exhaustive,
+    finish,
+    flat_map,
+    for_each,
+    from_raw,
+    from_str_radix,
     get,
     insert,
     int_roundings,
+    into_bytes,
+    into_owned,
     IntoIter,
+    is_ascii,
     is_empty,
+    is_err,
+    is_none,
     is_ok,
     is_some,
+    last,
+    LF: "\n",
     LowerExp,
     LowerHex,
+    max,
+    min,
+    mode,
     msrv,
     Octal,
     or_default,
+    parse,
+    push,
     regex,
+    reserve,
+    resize,
+    restriction,
     rustfmt_skip,
+    set_len,
+    set_mode,
+    set_readonly,
+    signum,
+    split_whitespace,
+    split,
     Start,
+    take,
+    TBD,
+    then_some,
+    to_digit,
     to_owned,
     unused_extern_crates,
     unwrap_err,
@@ -66,4 +108,6 @@ generate! {
     V4,
     V6,
     Weak,
+    with_capacity,
+    wrapping_offset,
 }