mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-10 15:14:29 +00:00
Extend useless_conversion
lint with TryInto
This commit is contained in:
parent
4f8909fad9
commit
705bfdcc46
5 changed files with 77 additions and 19 deletions
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@ -10,8 +10,8 @@ use rustc_middle::ty;
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use rustc_session::{declare_tool_lint, impl_lint_pass};
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declare_clippy_lint! {
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/// **What it does:** Checks for `Into`, `From`, `TryFrom`,`IntoIter` calls that useless converts
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/// to the same type as caller.
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/// **What it does:** Checks for `Into`, `TryInto`, `From`, `TryFrom`,`IntoIter` calls
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/// that useless converts to the same type as caller.
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///
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/// **Why is this bad?** Redundant code.
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///
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@ -29,7 +29,7 @@ declare_clippy_lint! {
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/// ```
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pub USELESS_CONVERSION,
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complexity,
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"calls to `Into`, `From`, `TryFrom`, `IntoIter` that performs useless conversions to the same type"
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"calls to `Into`, `TryInto`, `From`, `TryFrom`, `IntoIter` that performs useless conversions to the same type"
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}
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#[derive(Default)]
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@ -39,6 +39,7 @@ pub struct UselessConversion {
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impl_lint_pass!(UselessConversion => [USELESS_CONVERSION]);
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#[allow(clippy::too_many_lines)]
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessConversion {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
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if e.span.from_expansion() {
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@ -66,7 +67,6 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessConversion {
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let b = cx.tables.expr_ty(&args[0]);
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if same_tys(cx, a, b) {
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let sugg = snippet_with_macro_callsite(cx, args[0].span, "<expr>").to_string();
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span_lint_and_sugg(
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cx,
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USELESS_CONVERSION,
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@ -94,6 +94,27 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessConversion {
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);
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}
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}
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if match_trait_method(cx, e, &paths::TRY_INTO_TRAIT) && &*name.ident.as_str() == "try_into" {
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if_chain! {
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let a = cx.tables.expr_ty(e);
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let b = cx.tables.expr_ty(&args[0]);
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if is_type_diagnostic_item(cx, a, sym!(result_type));
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if let ty::Adt(_, substs) = a.kind;
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if let Some(a_type) = substs.types().next();
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if same_tys(cx, a_type, b);
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then {
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span_lint_and_help(
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cx,
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USELESS_CONVERSION,
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e.span,
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"Useless conversion to the same type",
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None,
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"consider removing `.try_into()`",
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);
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}
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}
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}
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},
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ExprKind::Call(ref path, ref args) => {
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@ -109,7 +130,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessConversion {
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if match_def_path(cx, def_id, &paths::TRY_FROM);
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if is_type_diagnostic_item(cx, a, sym!(result_type));
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if let ty::Adt(_, substs) = a.kind;
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if let Some(a_type) = substs.types().nth(0);
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if let Some(a_type) = substs.types().next();
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if same_tys(cx, a_type, b);
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then {
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@ -125,8 +146,11 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UselessConversion {
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}
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}
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if match_def_path(cx, def_id, &paths::FROM_FROM) {
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if same_tys(cx, a, b) {
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if_chain! {
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if match_def_path(cx, def_id, &paths::FROM_FROM);
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if same_tys(cx, a, b);
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then {
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let sugg = snippet(cx, args[0].span.source_callsite(), "<expr>").into_owned();
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let sugg_msg =
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format!("consider removing `{}()`", snippet(cx, path.span, "From::from"));
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@ -131,6 +131,7 @@ pub const TRANSMUTE: [&str; 4] = ["core", "intrinsics", "", "transmute"];
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pub const TRY_FROM: [&str; 4] = ["core", "convert", "TryFrom", "try_from"];
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pub const TRY_FROM_ERROR: [&str; 4] = ["std", "ops", "Try", "from_error"];
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pub const TRY_INTO_RESULT: [&str; 4] = ["std", "ops", "Try", "into_result"];
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pub const TRY_INTO_TRAIT: [&str; 3] = ["core", "convert", "TryInto"];
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pub const VEC: [&str; 3] = ["alloc", "vec", "Vec"];
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pub const VEC_AS_MUT_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_mut_slice"];
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pub const VEC_AS_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_slice"];
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@ -2421,7 +2421,7 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
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Lint {
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name: "useless_conversion",
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group: "complexity",
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desc: "calls to `Into`/`From`/`IntoIter` that performs useless conversions to the same type",
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desc: "calls to `Into`, `TryInto`, `From`, `TryFrom`, `IntoIter` that performs useless conversions to the same type",
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deprecation: None,
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module: "useless_conversion",
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},
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@ -1,12 +1,16 @@
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#![deny(clippy::useless_conversion)]
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use std::convert::TryFrom;
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use std::convert::{TryFrom, TryInto};
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fn test_generic<T: Copy>(val: T) -> T {
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T::try_from(val).unwrap()
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let _ = T::try_from(val).unwrap();
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val.try_into().unwrap()
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}
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fn test_generic2<T: Copy + Into<i32> + Into<U>, U: From<T>>(val: T) {
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// ok
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let _: i32 = val.try_into().unwrap();
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let _: U = val.try_into().unwrap();
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let _ = U::try_from(val).unwrap();
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}
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@ -14,12 +18,17 @@ fn main() {
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test_generic(10i32);
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test_generic2::<i32, i32>(10i32);
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let _: String = "foo".try_into().unwrap();
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let _: String = TryFrom::try_from("foo").unwrap();
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let _ = String::try_from("foo").unwrap();
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#[allow(clippy::useless_conversion)]
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let _ = String::try_from("foo").unwrap();
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{
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let _ = String::try_from("foo").unwrap();
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let _: String = "foo".try_into().unwrap();
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}
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let _: String = "foo".to_string().try_into().unwrap();
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let _: String = TryFrom::try_from("foo".to_string()).unwrap();
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let _ = String::try_from("foo".to_string()).unwrap();
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let _ = String::try_from(format!("A: {:04}", 123)).unwrap();
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let _: String = format!("Hello {}", "world").try_into().unwrap();
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}
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@ -1,8 +1,8 @@
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error: Useless conversion to the same type
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--> $DIR/useless_conversion_try.rs:6:5
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--> $DIR/useless_conversion_try.rs:6:13
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LL | T::try_from(val).unwrap()
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| ^^^^^^^^^^^^^^^^
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LL | let _ = T::try_from(val).unwrap();
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| ^^^^^^^^^^^^^^^^
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note: the lint level is defined here
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--> $DIR/useless_conversion_try.rs:1:9
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@ -12,7 +12,23 @@ LL | #![deny(clippy::useless_conversion)]
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= help: consider removing `T::try_from()`
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error: Useless conversion to the same type
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--> $DIR/useless_conversion_try.rs:22:21
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--> $DIR/useless_conversion_try.rs:7:5
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LL | val.try_into().unwrap()
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| ^^^^^^^^^^^^^^
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= help: consider removing `.try_into()`
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error: Useless conversion to the same type
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--> $DIR/useless_conversion_try.rs:29:21
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LL | let _: String = "foo".to_string().try_into().unwrap();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: consider removing `.try_into()`
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error: Useless conversion to the same type
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--> $DIR/useless_conversion_try.rs:30:21
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LL | let _: String = TryFrom::try_from("foo".to_string()).unwrap();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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@ -20,7 +36,7 @@ LL | let _: String = TryFrom::try_from("foo".to_string()).unwrap();
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= help: consider removing `TryFrom::try_from()`
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error: Useless conversion to the same type
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--> $DIR/useless_conversion_try.rs:23:13
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--> $DIR/useless_conversion_try.rs:31:13
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LL | let _ = String::try_from("foo".to_string()).unwrap();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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@ -28,12 +44,20 @@ LL | let _ = String::try_from("foo".to_string()).unwrap();
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= help: consider removing `String::try_from()`
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error: Useless conversion to the same type
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--> $DIR/useless_conversion_try.rs:24:13
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--> $DIR/useless_conversion_try.rs:32:13
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LL | let _ = String::try_from(format!("A: {:04}", 123)).unwrap();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: consider removing `String::try_from()`
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error: aborting due to 4 previous errors
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error: Useless conversion to the same type
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--> $DIR/useless_conversion_try.rs:33:21
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LL | let _: String = format!("Hello {}", "world").try_into().unwrap();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: consider removing `.try_into()`
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error: aborting due to 7 previous errors
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