Rewrite std_instead_of_core

tests/ui/std_instead_of_core.fixed

@@ -89,13 +89,6 @@ fn msrv_1_76(_: std::net::IpAddr) {}
 fn msrv_1_77(_: core::net::IpAddr) {}
 //~^ std_instead_of_core
 
-#[warn(clippy::alloc_instead_of_core)]
-fn issue15579() {
-    use std::alloc;
-
-    let layout = alloc::Layout::new::<u8>();
-}
-
 #[warn(clippy::std_instead_of_core)]
 fn issue13158_core_io() {
     // items moved from std::io into core::io are stable in an unstable module.
@@ -115,3 +108,26 @@ fn issue13158_msrv_1_80(_: &dyn std::error::Error) {}
 #[clippy::msrv = "1.81"]
 fn issue13158_msrv_1_81(_: &dyn core::error::Error) {}
 //~^ std_instead_of_core
+
+#[warn(clippy::std_instead_of_core)]
+fn issue17260() {
+    use core::concat;
+    //~^ std_instead_of_core
+}
+
+#[warn(clippy::std_instead_of_alloc)]
+fn non_use_paths() {
+    type Foo = alloc::sync::Arc<std::sync::Mutex<bool>>;
+    //~^ std_instead_of_alloc
+
+    let _x = core::iter::repeat(u8::default());
+    //~^ std_instead_of_core
+
+    fn impl_trait(_: impl core::fmt::Display) {}
+    //~^ std_instead_of_core
+
+    struct Bar {
+        layout: core::alloc::Layout,
+        //~^ std_instead_of_core
+    }
+}

tests/ui/std_instead_of_core.rs

@@ -89,13 +89,6 @@ fn msrv_1_76(_: std::net::IpAddr) {}
 fn msrv_1_77(_: std::net::IpAddr) {}
 //~^ std_instead_of_core
 
-#[warn(clippy::alloc_instead_of_core)]
-fn issue15579() {
-    use std::alloc;
-
-    let layout = alloc::Layout::new::<u8>();
-}
-
 #[warn(clippy::std_instead_of_core)]
 fn issue13158_core_io() {
     // items moved from std::io into core::io are stable in an unstable module.
@@ -115,3 +108,26 @@ fn issue13158_msrv_1_80(_: &dyn std::error::Error) {}
 #[clippy::msrv = "1.81"]
 fn issue13158_msrv_1_81(_: &dyn std::error::Error) {}
 //~^ std_instead_of_core
+
+#[warn(clippy::std_instead_of_core)]
+fn issue17260() {
+    use std::concat;
+    //~^ std_instead_of_core
+}
+
+#[warn(clippy::std_instead_of_alloc)]
+fn non_use_paths() {
+    type Foo = std::sync::Arc<std::sync::Mutex<bool>>;
+    //~^ std_instead_of_alloc
+
+    let _x = std::iter::repeat(u8::default());
+    //~^ std_instead_of_core
+
+    fn impl_trait(_: impl std::fmt::Display) {}
+    //~^ std_instead_of_core
+
+    struct Bar {
+        layout: std::alloc::Layout,
+        //~^ std_instead_of_core
+    }
+}

tests/ui/std_instead_of_core.stderr

@@ -98,16 +98,46 @@ LL | fn msrv_1_77(_: std::net::IpAddr) {}
    |                 ^^^ help: consider importing the item from `core`: `core`
 
 error: used import from `std` instead of `core`
-  --> tests/ui/std_instead_of_core.rs:109:33
+  --> tests/ui/std_instead_of_core.rs:102:33
    |
 LL | fn issue13158_msrv_1_41(_: &dyn std::panic::UnwindSafe) {}
    |                                 ^^^ help: consider importing the item from `core`: `core`
 
 error: used import from `std` instead of `core`
-  --> tests/ui/std_instead_of_core.rs:116:33
+  --> tests/ui/std_instead_of_core.rs:109:33
    |
 LL | fn issue13158_msrv_1_81(_: &dyn std::error::Error) {}
    |                                 ^^^ help: consider importing the item from `core`: `core`
 
-error: aborting due to 17 previous errors
+error: used import from `std` instead of `core`
+  --> tests/ui/std_instead_of_core.rs:114:9
+   |
+LL |     use std::concat;
+   |         ^^^ help: consider importing the item from `core`: `core`
+
+error: used import from `std` instead of `alloc`
+  --> tests/ui/std_instead_of_core.rs:120:16
+   |
+LL |     type Foo = std::sync::Arc<std::sync::Mutex<bool>>;
+   |                ^^^ help: consider importing the item from `alloc`: `alloc`
+
+error: used import from `std` instead of `core`
+  --> tests/ui/std_instead_of_core.rs:123:14
+   |
+LL |     let _x = std::iter::repeat(u8::default());
+   |              ^^^ help: consider importing the item from `core`: `core`
+
+error: used import from `std` instead of `core`
+  --> tests/ui/std_instead_of_core.rs:126:27
+   |
+LL |     fn impl_trait(_: impl std::fmt::Display) {}
+   |                           ^^^ help: consider importing the item from `core`: `core`
+
+error: used import from `std` instead of `core`
+  --> tests/ui/std_instead_of_core.rs:130:17
+   |
+LL |         layout: std::alloc::Layout,
+   |                 ^^^ help: consider importing the item from `core`: `core`
+
+error: aborting due to 22 previous errors
 

tests/ui/std_instead_of_core_local_alloc.fixed

@@ -0,0 +1,37 @@
+#![warn(clippy::std_instead_of_alloc)]
+#![allow(unused_imports)]
+
+#[rustfmt::skip]
+fn issue16695() {
+    extern crate alloc;
+
+    use alloc::collections::VecDeque;
+    //~^ std_instead_of_alloc
+
+    {
+        use alloc::vec::Vec;
+        //~^ std_instead_of_alloc
+    }
+}
+
+mod a {
+    extern crate alloc as alloc_a;
+
+    fn b() {
+        mod c {
+            extern crate alloc as alloc_b;
+
+            fn d() {
+                fn e() {
+                    // This should suggest alloc_b
+                    use alloc_b::vec::Vec;
+                    //~^ std_instead_of_alloc
+                }
+            }
+        }
+    }
+
+    // This should suggest alloc_a
+    use alloc_a::vec::Vec;
+    //~^ std_instead_of_alloc
+}

tests/ui/std_instead_of_core_local_alloc.rs

@@ -0,0 +1,37 @@
+#![warn(clippy::std_instead_of_alloc)]
+#![allow(unused_imports)]
+
+#[rustfmt::skip]
+fn issue16695() {
+    extern crate alloc;
+
+    use std::collections::VecDeque;
+    //~^ std_instead_of_alloc
+
+    {
+        use std::vec::Vec;
+        //~^ std_instead_of_alloc
+    }
+}
+
+mod a {
+    extern crate alloc as alloc_a;
+
+    fn b() {
+        mod c {
+            extern crate alloc as alloc_b;
+
+            fn d() {
+                fn e() {
+                    // This should suggest alloc_b
+                    use std::vec::Vec;
+                    //~^ std_instead_of_alloc
+                }
+            }
+        }
+    }
+
+    // This should suggest alloc_a
+    use std::vec::Vec;
+    //~^ std_instead_of_alloc
+}

tests/ui/std_instead_of_core_local_alloc.stderr

@@ -0,0 +1,29 @@
+error: used import from `std` instead of `alloc`
+  --> tests/ui/std_instead_of_core_local_alloc.rs:8:9
+   |
+LL |     use std::collections::VecDeque;
+   |         ^^^ help: consider importing the item from `alloc`: `alloc`
+   |
+   = note: `-D clippy::std-instead-of-alloc` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::std_instead_of_alloc)]`
+
+error: used import from `std` instead of `alloc`
+  --> tests/ui/std_instead_of_core_local_alloc.rs:12:13
+   |
+LL |         use std::vec::Vec;
+   |             ^^^ help: consider importing the item from `alloc`: `alloc`
+
+error: used import from `std` instead of `alloc`
+  --> tests/ui/std_instead_of_core_local_alloc.rs:27:25
+   |
+LL |                     use std::vec::Vec;
+   |                         ^^^ help: consider importing the item from `alloc`: `alloc_b`
+
+error: used import from `std` instead of `alloc`
+  --> tests/ui/std_instead_of_core_local_alloc.rs:35:9
+   |
+LL |     use std::vec::Vec;
+   |         ^^^ help: consider importing the item from `alloc`: `alloc_a`
+
+error: aborting due to 4 previous errors
+

tests/ui/std_instead_of_core_unfixable.rs

@@ -23,3 +23,100 @@ fn pr16964() {
         ffi::OsString,
     };
 }
+
+#[warn(clippy::alloc_instead_of_core)]
+fn issue15579() {
+    use std::alloc;
+
+    let layout = alloc::Layout::new::<u8>();
+    //~^ std_instead_of_core
+}
+
+#[rustfmt::skip]
+fn issue12468() {
+    use std::{
+        fmt::Result,
+        //~^ std_instead_of_core
+        io::Write,
+    };
+
+    use std::sync::{
+        Arc,
+        //~^ std_instead_of_alloc
+        Mutex,
+    };
+}
+
+#[allow(clippy::legacy_numeric_constants)]
+#[warn(clippy::alloc_instead_of_core)]
+#[rustfmt::skip]
+fn pr17252_large() {
+    extern crate alloc;
+
+    use {
+        std::sync::Mutex,
+        ::{
+            std::{
+                fmt::{*, Formatter},
+                //~^ std_instead_of_alloc
+                //~| std_instead_of_core
+                fs,
+                //~v std_instead_of_core
+                sync::atomic,
+                //~v std_instead_of_core
+                sync::atomic::{
+                    AtomicUsize,
+                    AtomicU8,
+                    Ordering,
+                },
+            },
+            core::u32,
+            std::collections::HashMap,
+        },
+        alloc::{
+            fmt::Result as FmtResult,
+            //~^ alloc_instead_of_core
+            format,
+        }
+    };
+}
+
+#[warn(clippy::alloc_instead_of_core)]
+#[rustfmt::skip]
+fn issue11159() {
+    use std::fmt;
+    //~^ std_instead_of_alloc
+
+    struct S;
+
+    impl fmt::Display for S {
+        //~^ alloc_instead_of_core
+        fn fmt(
+            &self,
+            _: &mut fmt::Formatter<'_>,
+            //~^ alloc_instead_of_core
+        ) -> fmt::Result {
+            //~^ alloc_instead_of_core
+            todo!()
+        }
+    }
+}
+
+#[warn(clippy::alloc_instead_of_core)]
+#[rustfmt::skip]
+fn mixed_name_spaces() {
+    extern crate alloc;
+
+    use std::{
+        io,
+        iter::repeat_with,
+        //~^ std_instead_of_core
+    };
+
+    use alloc::alloc::{
+        alloc,
+        dealloc,
+        Layout,
+        //~^ alloc_instead_of_core
+    };
+}