Make ui/suggestions/suggest-tryinto-edition-change.rs no_std to avoid getting inconsistent output between local and CI.

Author: JakobDegen

src/test/ui/suggestions/suggest-tryinto-edition-change.rs

@@ -2,30 +2,28 @@
 // Edition 2021 change
 // edition:2018
 
-fn test() {
-    let _i: i16 = 0_i32.try_into().unwrap();
+// We mark this no_std to avoid emitting suggestions for both `std` and `core` traits. These were
+// inconsistently ordered between CI and at least one local build, causing test failures.
+#![no_std]
+#![crate_type = "lib"]
+
+pub fn test() {
+    let _i: Result<i16, _> = 0_i32.try_into();
     //~^ ERROR no method named `try_into` found for type `i32` in the current scope
     //~| NOTE method not found in `i32`
-    //~| NOTE 'std::convert::TryInto' is included in the prelude starting in Edition 2021
+    //~| NOTE 'core::convert::TryInto' is included in the prelude starting in Edition 2021
 
-    let _i: i16 = TryFrom::try_from(0_i32).unwrap();
+    let _i: Result<i16, _> = TryFrom::try_from(0_i32);
     //~^ ERROR failed to resolve: use of undeclared type
     //~| NOTE not found in this scope
-    //~| NOTE 'std::convert::TryFrom' is included in the prelude starting in Edition 2021
     //~| NOTE 'core::convert::TryFrom' is included in the prelude starting in Edition 2021
 
-    let _i: i16 = TryInto::try_into(0_i32).unwrap();
+    let _i: Result<i16, _> = TryInto::try_into(0_i32);
     //~^ ERROR failed to resolve: use of undeclared type
     //~| NOTE not found in this scope
-    //~| NOTE 'std::convert::TryInto' is included in the prelude starting in Edition 2021
     //~| NOTE 'core::convert::TryInto' is included in the prelude starting in Edition 2021
 
-    let _v: Vec<_> = FromIterator::from_iter(&[1]);
+    let _i: () = FromIterator::from_iter(core::iter::empty());
     //~^ ERROR failed to resolve: use of undeclared type
-    //~| NOTE 'std::iter::FromIterator' is included in the prelude starting in Edition 2021
     //~| NOTE 'core::iter::FromIterator' is included in the prelude starting in Edition 2021
 }
-
-fn main() {
-    test();
-}

src/test/ui/suggestions/suggest-tryinto-edition-change.stderr

@@ -1,73 +1,64 @@
 error[E0433]: failed to resolve: use of undeclared type `TryFrom`
-  --> $DIR/suggest-tryinto-edition-change.rs:11:19
+  --> $DIR/suggest-tryinto-edition-change.rs:14:30
    |
-LL |     let _i: i16 = TryFrom::try_from(0_i32).unwrap();
-   |                   ^^^^^^^ not found in this scope
+LL |     let _i: Result<i16, _> = TryFrom::try_from(0_i32);
+   |                              ^^^^^^^ not found in this scope
    |
-   = note: 'std::convert::TryFrom' is included in the prelude starting in Edition 2021
    = note: 'core::convert::TryFrom' is included in the prelude starting in Edition 2021
-help: consider importing one of these items
-   |
-LL | use std::convert::TryFrom;
+help: consider importing this trait
    |
 LL | use core::convert::TryFrom;
    |
 
 error[E0433]: failed to resolve: use of undeclared type `TryInto`
-  --> $DIR/suggest-tryinto-edition-change.rs:17:19
+  --> $DIR/suggest-tryinto-edition-change.rs:19:30
    |
-LL |     let _i: i16 = TryInto::try_into(0_i32).unwrap();
-   |                   ^^^^^^^ not found in this scope
+LL |     let _i: Result<i16, _> = TryInto::try_into(0_i32);
+   |                              ^^^^^^^ not found in this scope
    |
-   = note: 'std::convert::TryInto' is included in the prelude starting in Edition 2021
    = note: 'core::convert::TryInto' is included in the prelude starting in Edition 2021
-help: consider importing one of these items
-   |
-LL | use std::convert::TryInto;
+help: consider importing this trait
    |
 LL | use core::convert::TryInto;
    |
 
 error[E0433]: failed to resolve: use of undeclared type `FromIterator`
-  --> $DIR/suggest-tryinto-edition-change.rs:23:22
+  --> $DIR/suggest-tryinto-edition-change.rs:24:18
    |
-LL |     let _v: Vec<_> = FromIterator::from_iter(&[1]);
-   |                      ^^^^^^^^^^^^
+LL |     let _i: () = FromIterator::from_iter(core::iter::empty());
+   |                  ^^^^^^^^^^^^
    |
   ::: $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
    |
 LL | pub trait IntoIterator {
    | ---------------------- similarly named trait `IntoIterator` defined here
    |
-   = note: 'std::iter::FromIterator' is included in the prelude starting in Edition 2021
    = note: 'core::iter::FromIterator' is included in the prelude starting in Edition 2021
 help: a trait with a similar name exists
    |
-LL |     let _v: Vec<_> = IntoIterator::from_iter(&[1]);
-   |                      ~~~~~~~~~~~~
-help: consider importing one of these items
-   |
-LL | use std::iter::FromIterator;
+LL |     let _i: () = IntoIterator::from_iter(core::iter::empty());
+   |                  ~~~~~~~~~~~~
+help: consider importing this trait
    |
 LL | use core::iter::FromIterator;
    |
 
 error[E0599]: no method named `try_into` found for type `i32` in the current scope
-  --> $DIR/suggest-tryinto-edition-change.rs:6:25
+  --> $DIR/suggest-tryinto-edition-change.rs:9:36
    |
-LL |     let _i: i16 = 0_i32.try_into().unwrap();
-   |                         ^^^^^^^^ method not found in `i32`
+LL |     let _i: Result<i16, _> = 0_i32.try_into();
+   |                                    ^^^^^^^^ method not found in `i32`
    |
   ::: $SRC_DIR/core/src/convert/mod.rs:LL:COL
    |
 LL |     fn try_into(self) -> Result<T, Self::Error>;
    |        -------- the method is available for `i32` here
    |
    = help: items from traits can only be used if the trait is in scope
-   = note: 'std::convert::TryInto' is included in the prelude starting in Edition 2021
+   = note: 'core::convert::TryInto' is included in the prelude starting in Edition 2021
 help: the following trait is implemented but not in scope; perhaps add a `use` for it:
    |
-LL | use std::convert::TryInto;
+LL | use core::convert::TryInto;
    |
 
 error: aborting due to 4 previous errors