same for tuple structs

Author: ada4a

clippy_utils/src/lib.rs

@@ -1913,6 +1913,9 @@ fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
             return false;
         }
 
+        // NOTE: we're inside a (function) body, so this won't ICE
+        let qpath_res = |qpath, hir| cx.typeck_results().qpath_res(qpath, hir);
+
         match (pat.kind, expr.kind) {
             (PatKind::Binding(_, id, _, _), _) => {
                 path_to_local_id(expr, id) && cx.typeck_results().expr_adjustments(expr).is_empty()
@@ -1929,12 +1932,20 @@ fn is_body_identity_function(cx: &LateContext<'_>, func: &Body<'_>) -> bool {
                     .zip(arr)
                     .all(|(pat, expr)| check_pat(cx, pat, expr))
             },
+            (PatKind::TupleStruct(pat_ident, field_pats, dotdot), ExprKind::Call(ident, fields))
+                if dotdot.as_opt_usize().is_none()
+                    && let ExprKind::Path(ident) = ident.kind =>
+            {
+                field_pats.len() == fields.len()
+                    && qpath_res(&pat_ident, pat.hir_id) == qpath_res(&ident, expr.hir_id)
+                    && (field_pats.iter())
+                        .zip(fields)
+                        .all(|(pat, expr)| check_pat(cx, pat, expr))
+            },
             (
                 PatKind::Struct(pat_ident, field_pats, false),
                 ExprKind::Struct(ident, fields, hir::StructTailExpr::None),
             ) => {
-                // NOTE: we're inside a (function) body, so this won't ICE
-                let qpath_res = |qpath, hir| cx.typeck_results().qpath_res(qpath, hir);
                 field_pats.len() == fields.len()
                     && qpath_res(&pat_ident, pat.hir_id) == qpath_res(ident, expr.hir_id)
                     && field_pats.iter().all(|field_pat| {

tests/ui/f1.fixed

@@ -7,15 +7,20 @@ mod foo {
         pub foo: u8,
         pub bar: u8,
     }
+
+    #[derive(Clone, Copy)]
+    pub struct Foo2(pub u8, pub u8);
 }
-use foo::Foo;
+use foo::{Foo, Foo2};
 
 struct Bar {
     foo: u8,
     bar: u8,
 }
 
-fn main() {
+struct Bar2(u8, u8);
+
+fn structs() {
     let x = [Foo { foo: 0, bar: 0 }];
 
     let _ = x.into_iter();
@@ -40,3 +45,20 @@ fn main() {
     // don't lint: switched field assignment
     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo: bar, bar: foo });
 }
+
+fn tuple_structs() {
+    let x = [Foo2(0, 0)];
+
+    let _ = x.into_iter();
+    //~^ map_identity
+
+    // still lint when different paths are used for the same struct
+    let _ = x.into_iter();
+    //~^ map_identity
+
+    // don't lint: same fields but different structs
+    let _ = x.into_iter().map(|Foo2(foo, bar)| Bar2(foo, bar));
+
+    // don't lint: switched field assignment
+    let _ = x.into_iter().map(|Foo2(foo, bar)| Foo2(bar, foo));
+}

tests/ui/f1.rs

@@ -7,15 +7,20 @@ mod foo {
         pub foo: u8,
         pub bar: u8,
     }
+
+    #[derive(Clone, Copy)]
+    pub struct Foo2(pub u8, pub u8);
 }
-use foo::Foo;
+use foo::{Foo, Foo2};
 
 struct Bar {
     foo: u8,
     bar: u8,
 }
 
-fn main() {
+struct Bar2(u8, u8);
+
+fn structs() {
     let x = [Foo { foo: 0, bar: 0 }];
 
     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo, bar });
@@ -40,3 +45,20 @@ fn main() {
     // don't lint: switched field assignment
     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo: bar, bar: foo });
 }
+
+fn tuple_structs() {
+    let x = [Foo2(0, 0)];
+
+    let _ = x.into_iter().map(|Foo2(foo, bar)| Foo2(foo, bar));
+    //~^ map_identity
+
+    // still lint when different paths are used for the same struct
+    let _ = x.into_iter().map(|Foo2(foo, bar)| foo::Foo2(foo, bar));
+    //~^ map_identity
+
+    // don't lint: same fields but different structs
+    let _ = x.into_iter().map(|Foo2(foo, bar)| Bar2(foo, bar));
+
+    // don't lint: switched field assignment
+    let _ = x.into_iter().map(|Foo2(foo, bar)| Foo2(bar, foo));
+}

tests/ui/f1.stderr

@@ -1,5 +1,5 @@
 error: unnecessary map of the identity function
-  --> tests/ui/f1.rs:21:26
+  --> tests/ui/f1.rs:26:26
    |
 LL |     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo, bar });
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
@@ -8,22 +8,34 @@ LL |     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo, bar });
    = help: to override `-D warnings` add `#[allow(clippy::map_identity)]`
 
 error: unnecessary map of the identity function
-  --> tests/ui/f1.rs:25:26
+  --> tests/ui/f1.rs:30:26
    |
 LL |     let _ = x.into_iter().map(|Foo { foo, bar }| foo::Foo { foo, bar });
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
 
 error: unnecessary map of the identity function
-  --> tests/ui/f1.rs:33:26
+  --> tests/ui/f1.rs:38:26
    |
 LL |     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo: foo, bar: bar });
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
 
 error: unnecessary map of the identity function
-  --> tests/ui/f1.rs:37:26
+  --> tests/ui/f1.rs:42:26
    |
 LL |     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { bar, foo });
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
 
-error: aborting due to 4 previous errors
+error: unnecessary map of the identity function
+  --> tests/ui/f1.rs:52:26
+   |
+LL |     let _ = x.into_iter().map(|Foo2(foo, bar)| Foo2(foo, bar));
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
+
+error: unnecessary map of the identity function
+  --> tests/ui/f1.rs:56:26
+   |
+LL |     let _ = x.into_iter().map(|Foo2(foo, bar)| foo::Foo2(foo, bar));
+   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
+
+error: aborting due to 6 previous errors