Make more traits of the From/Into family diagnostic items

Following traits are now diagnostic items:
- `From` (unchanged)
- `Into`
- `TryFrom`
- `TryInto`

This also adds symbols for those items:
- `into_trait`
- `try_from_trait`
- `try_into_trait`

Author: flip1995

clippy_lints/src/fallible_impl_from.rs

@@ -1,7 +1,4 @@
-use crate::utils::paths::FROM_TRAIT;
-use crate::utils::{
-    is_expn_of, is_type_diagnostic_item, match_def_path, match_panic_def_id, method_chain_args, span_lint_and_then,
-};
+use crate::utils::{is_expn_of, is_type_diagnostic_item, match_panic_def_id, method_chain_args, span_lint_and_then};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
@@ -59,7 +56,7 @@ impl<'tcx> LateLintPass<'tcx> for FallibleImplFrom {
         if_chain! {
             if let hir::ItemKind::Impl(impl_) = &item.kind;
             if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(impl_def_id);
-            if match_def_path(cx, impl_trait_ref.def_id, &FROM_TRAIT);
+            if cx.tcx.is_diagnostic_item(sym::from_trait, impl_trait_ref.def_id);
             then {
                 lint_impl_body(cx, item.span, impl_.items);
             }

clippy_lints/src/utils/paths.rs

@@ -48,7 +48,6 @@ pub const FN_MUT: [&str; 3] = ["core", "ops", "FnMut"];
 pub const FN_ONCE: [&str; 3] = ["core", "ops", "FnOnce"];
 pub const FROM_FROM: [&str; 4] = ["core", "convert", "From", "from"];
 pub const FROM_ITERATOR: [&str; 5] = ["core", "iter", "traits", "collect", "FromIterator"];
-pub const FROM_TRAIT: [&str; 3] = ["core", "convert", "From"];
 pub const FUTURE_FROM_GENERATOR: [&str; 3] = ["core", "future", "from_generator"];
 pub const HASH: [&str; 3] = ["core", "hash", "Hash"];
 pub const HASHMAP: [&str; 5] = ["std", "collections", "hash", "map", "HashMap"];