Use diagnostic items for intrinsics::transmute, TryInto

Author: xFrednet

clippy_lints/src/transmute/mod.rs

@@ -12,11 +12,12 @@ mod useless_transmute;
 mod utils;
 mod wrong_transmute;
 
-use clippy_utils::{in_constant, match_def_path, paths};
+use clippy_utils::in_constant;
 use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for transmutes that can't ever be correct on any
@@ -328,7 +329,7 @@ impl<'tcx> LateLintPass<'tcx> for Transmute {
             if let ExprKind::Call(path_expr, args) = e.kind;
             if let ExprKind::Path(ref qpath) = path_expr.kind;
             if let Some(def_id) = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id();
-            if match_def_path(cx, def_id, &paths::TRANSMUTE);
+            if cx.tcx.is_diagnostic_item(sym::transmute, def_id);
             then {
                 // Avoid suggesting from/to bits and dereferencing raw pointers in const contexts.
                 // See https://github.com/rust-lang/rust/issues/73736 for progress on making them `const fn`.

clippy_lints/src/transmuting_null.rs

@@ -1,6 +1,6 @@
 use clippy_utils::consts::{constant_context, Constant};
 use clippy_utils::diagnostics::span_lint;
-use clippy_utils::{is_expr_diagnostic_item, is_expr_path_def_path, paths};
+use clippy_utils::is_expr_diagnostic_item;
 use if_chain::if_chain;
 use rustc_ast::LitKind;
 use rustc_hir::{Expr, ExprKind};
@@ -39,7 +39,7 @@ impl<'tcx> LateLintPass<'tcx> for TransmutingNull {
 
         if_chain! {
             if let ExprKind::Call(func, [arg]) = expr.kind;
-            if is_expr_path_def_path(cx, func, &paths::TRANSMUTE);
+            if is_expr_diagnostic_item(cx, func, sym::transmute);
 
             then {
                 // Catching transmute over constants that resolve to `null`.

clippy_lints/src/useless_conversion.rs

@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg};
 use clippy_utils::source::{snippet, snippet_with_macro_callsite};
 use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::{is_type_diagnostic_item, same_type_and_consts};
-use clippy_utils::{get_parent_expr, is_trait_method, match_def_path, match_trait_method, paths};
+use clippy_utils::{get_parent_expr, is_trait_method, match_def_path, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, HirId, MatchSource};
@@ -104,7 +104,7 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
                     }
                 }
                 if_chain! {
-                    if match_trait_method(cx, e, &paths::TRY_INTO_TRAIT) && name.ident.name == sym::try_into;
+                    if is_trait_method(cx, e, sym::try_into_trait) && name.ident.name == sym::try_into;
                     let a = cx.typeck_results().expr_ty(e);
                     let b = cx.typeck_results().expr_ty(&args[0]);
                     if is_type_diagnostic_item(cx, a, sym::result_type);

clippy_utils/src/paths.rs

@@ -145,6 +145,7 @@ pub const REGEX_BYTES_NEW: [&str; 4] = ["regex", "re_bytes", "Regex", "new"];
 pub const REGEX_BYTES_SET_NEW: [&str; 5] = ["regex", "re_set", "bytes", "RegexSet", "new"];
 pub const REGEX_NEW: [&str; 4] = ["regex", "re_unicode", "Regex", "new"];
 pub const REGEX_SET_NEW: [&str; 5] = ["regex", "re_set", "unicode", "RegexSet", "new"];
+/// Preferably use the diagnostic item `sym::result_type` where possible
 pub const RESULT: [&str; 3] = ["core", "result", "Result"];
 pub const RESULT_ERR: [&str; 4] = ["core", "result", "Result", "Err"];
 pub const RESULT_OK: [&str; 4] = ["core", "result", "Result", "Ok"];
@@ -180,9 +181,8 @@ pub const SYM_MODULE: [&str; 3] = ["rustc_span", "symbol", "sym"];
 pub const SYNTAX_CONTEXT: [&str; 3] = ["rustc_span", "hygiene", "SyntaxContext"];
 pub const TO_OWNED_METHOD: [&str; 4] = ["alloc", "borrow", "ToOwned", "to_owned"];
 pub const TO_STRING_METHOD: [&str; 4] = ["alloc", "string", "ToString", "to_string"];
-pub const TRANSMUTE: [&str; 4] = ["core", "intrinsics", "", "transmute"];
 pub const TRY_FROM: [&str; 4] = ["core", "convert", "TryFrom", "try_from"];
-pub const TRY_INTO_TRAIT: [&str; 3] = ["core", "convert", "TryInto"];
+
 pub const VEC: [&str; 3] = ["alloc", "vec", "Vec"];
 pub const VEC_AS_MUT_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_mut_slice"];
 pub const VEC_AS_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_slice"];