Auto merge of #8596 - Jaic1:unnecessary_cast, r=flip1995

Fix unnecessary_cast suggestion for type aliasses

Fix #6923. The [`unnecessary_cast`] lint now will skip casting to non-primitive type.

changelog: fix lint [`unnecessary_cast `]

3 files changed, 16 insertions, 0 deletions

diff --git a/tests/ui/unnecessary_cast.rs b/tests/ui/unnecessary_cast.rs
index b77c19f2ba5..62c3e963686 100644
--- a/tests/ui/unnecessary_cast.rs
+++ b/tests/ui/unnecessary_cast.rs
@@ -30,4 +30,10 @@ fn main() {
 
     // do not lint cast to cfg-dependant type
     1 as std::os::raw::c_char;
+
+    // do not lint cast to alias type
+    1 as I32Alias;
+    &1 as &I32Alias;
 }
+
+type I32Alias = i32;
diff --git a/tests/ui/unnecessary_cast_fixable.fixed b/tests/ui/unnecessary_cast_fixable.fixed
index 3332f49c80c..36800c5340d 100644
--- a/tests/ui/unnecessary_cast_fixable.fixed
+++ b/tests/ui/unnecessary_cast_fixable.fixed
@@ -42,4 +42,9 @@ fn main() {
 
     let _ = -1_i32;
     let _ = -1.0_f32;
+
+    let _ = 1 as I32Alias;
+    let _ = &1 as &I32Alias;
 }
+
+type I32Alias = i32;
diff --git a/tests/ui/unnecessary_cast_fixable.rs b/tests/ui/unnecessary_cast_fixable.rs
index ec01e938779..d4b6bb952ab 100644
--- a/tests/ui/unnecessary_cast_fixable.rs
+++ b/tests/ui/unnecessary_cast_fixable.rs
@@ -42,4 +42,9 @@ fn main() {
 
     let _ = -1 as i32;
     let _ = -1.0 as f32;
+
+    let _ = 1 as I32Alias;
+    let _ = &1 as &I32Alias;
 }
+
+type I32Alias = i32;