fix(lint): std_instead_of_core false positive for core::io

Author: bushrat011899

clippy_lints/src/std_instead_of_core.rs

@@ -237,21 +237,33 @@ fn get_first_segment<'tcx>(path: &Path<'tcx>) -> Option<&'tcx PathSegment<'tcx>>
 ///
 /// Does not catch individually moved items
 fn is_stable(cx: &LateContext<'_>, mut def_id: DefId, msrv: Msrv) -> bool {
+    let mut allowed_through_unstable_modules_seen = false;
     loop {
-        if let Some(stability) = cx.tcx.lookup_stability(def_id)
-            && let StabilityLevel::Stable {
-                since,
-                allowed_through_unstable_modules: None,
-            } = stability.level
-        {
-            let stable = match since {
-                StableSince::Version(v) => msrv.meets(cx, v),
-                StableSince::Current => msrv.current(cx).is_none(),
-                StableSince::Err(_) => false,
-            };
+        if let Some(stability) = cx.tcx.lookup_stability(def_id) {
+            match stability.level {
+                StabilityLevel::Unstable { .. } => {
+                    if !allowed_through_unstable_modules_seen {
+                        return false;
+                    }
+                },
+                StabilityLevel::Stable {
+                    since,
+                    allowed_through_unstable_modules,
+                } => {
+                    let stable = match since {
+                        StableSince::Version(v) => msrv.meets(cx, v),
+                        StableSince::Current => msrv.current(cx).is_none(),
+                        StableSince::Err(_) => false,
+                    };
 
-            if !stable {
-                return false;
+                    if allowed_through_unstable_modules.is_some() {
+                        allowed_through_unstable_modules_seen = true;
+                    }
+
+                    if !stable && allowed_through_unstable_modules.is_none() {
+                        return false;
+                    }
+                },
             }
         }
 

tests/ui/std_instead_of_core.fixed

@@ -96,3 +96,19 @@ fn issue15579() {
 
     let layout = alloc::Layout::new::<u8>();
 }
+
+#[warn(clippy::std_instead_of_core)]
+#[warn(clippy::std_instead_of_alloc)]
+fn issue13158_core_io() {
+    // items moved from std::io into core::io are stable in an unstable module.
+    use std::io::ErrorKind;
+
+    #[rustfmt::skip]
+    use std::sync::{
+        Arc,
+        //~^ std_instead_of_alloc
+        Mutex,
+        Weak,
+        //~^ std_instead_of_alloc
+    };
+}

tests/ui/std_instead_of_core.rs

@@ -96,3 +96,19 @@ fn issue15579() {
 
     let layout = alloc::Layout::new::<u8>();
 }
+
+#[warn(clippy::std_instead_of_core)]
+#[warn(clippy::std_instead_of_alloc)]
+fn issue13158_core_io() {
+    // items moved from std::io into core::io are stable in an unstable module.
+    use std::io::ErrorKind;
+
+    #[rustfmt::skip]
+    use std::sync::{
+        Arc,
+        //~^ std_instead_of_alloc
+        Mutex,
+        Weak,
+        //~^ std_instead_of_alloc
+    };
+}

tests/ui/std_instead_of_core.stderr

@@ -97,5 +97,20 @@ error: used import from `std` instead of `core`
 LL | fn msrv_1_77(_: std::net::IpAddr) {}
    |                 ^^^ help: consider importing the item from `core`: `core`
 
-error: aborting due to 15 previous errors
+error: used import from `std` instead of `alloc`
+  --> tests/ui/std_instead_of_core.rs:108:9
+   |
+LL |         Arc,
+   |         ^^^
+   |
+   = help: consider importing the item from `alloc`
+
+error: used import from `std` instead of `alloc`
+  --> tests/ui/std_instead_of_core.rs:111:9
+   |
+LL |         Weak,
+   |         ^^^^
+   |
+   = help: consider importing the item from `alloc`
 
+error: aborting due to 17 previous errors