make the unfixable case fixable by using path_to_local_with_projections

Author: ada4a

clippy_lints/src/methods/map_identity.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::ty::is_type_diagnostic_item;
-use clippy_utils::{is_expr_untyped_identity_function, is_mutable, is_trait_method, path_to_local};
+use clippy_utils::{is_expr_untyped_identity_function, is_mutable, is_trait_method, path_to_local_with_projections};
 use rustc_errors::Applicability;
 use rustc_hir::{self as hir, ExprKind, Node, PatKind};
 use rustc_lint::LateContext;
@@ -27,7 +27,7 @@ pub(super) fn check(
         let mut sugg = vec![(call_span, String::new())];
         let mut apply = true;
         if !is_mutable(cx, caller) {
-            if let Some(hir_id) = path_to_local(caller)
+            if let Some(hir_id) = path_to_local_with_projections(caller)
                 && let Node::Pat(pat) = cx.tcx.hir_node(hir_id)
                 && let PatKind::Binding(_, _, ident, _) = pat.kind
             {

tests/ui/map_identity.fixed

@@ -79,6 +79,12 @@ fn issue13904() {
     let _ = it.next();
     //~^ map_identity
 
+    // lint
+    let mut index = [1, 2, 3].into_iter();
+    let mut subindex = (index.by_ref().take(3), 42);
+    let _ = subindex.0.next();
+    //~^ map_identity
+
     // lint
     #[allow(unused_mut)]
     let mut it = [1, 2, 3].into_iter();

tests/ui/map_identity.rs

@@ -85,6 +85,12 @@ fn issue13904() {
     let _ = it.map(|x| x).next();
     //~^ map_identity
 
+    // lint
+    let mut index = [1, 2, 3].into_iter();
+    let subindex = (index.by_ref().take(3), 42);
+    let _ = subindex.0.map(|n| n).next();
+    //~^ map_identity
+
     // lint
     #[allow(unused_mut)]
     let mut it = [1, 2, 3].into_iter();

tests/ui/map_identity.stderr

@@ -88,58 +88,70 @@ LL ~     let _ = it.next();
    |
 
 error: unnecessary map of the identity function
-  --> tests/ui/map_identity.rs:91:15
+  --> tests/ui/map_identity.rs:91:23
+   |
+LL |     let _ = subindex.0.map(|n| n).next();
+   |                       ^^^^^^^^^^^
+   |
+help: remove the call to `map`
+   |
+LL ~     let mut subindex = (index.by_ref().take(3), 42);
+LL ~     let _ = subindex.0.next();
+   |
+
+error: unnecessary map of the identity function
+  --> tests/ui/map_identity.rs:97:15
    |
 LL |     let _ = it.map(|x| x).next();
    |               ^^^^^^^^^^^ help: remove the call to `map`
 
 error: unnecessary map of the identity function
-  --> tests/ui/map_identity.rs:96:19
+  --> tests/ui/map_identity.rs:102:19
    |
 LL |     let _ = { it }.map(|x| x).next();
    |                   ^^^^^^^^^^^ help: remove the call to `map`
 
 error: unnecessary map of the identity function
-  --> tests/ui/map_identity.rs:108:30
+  --> tests/ui/map_identity.rs:114:30
    |
 LL |     let _ = x.iter().copied().map(|[x, y]| [x, y]);
    |                              ^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
 
 error: unnecessary map of the identity function
-  --> tests/ui/map_identity.rs:134:26
+  --> tests/ui/map_identity.rs:140:26
    |
 LL |     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { foo, bar });
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
 
 error: unnecessary map of the identity function
-  --> tests/ui/map_identity.rs:138:26
+  --> tests/ui/map_identity.rs:144:26
    |
 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/map_identity.rs:146:26
+  --> tests/ui/map_identity.rs:152:26
    |
 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/map_identity.rs:150:26
+  --> tests/ui/map_identity.rs:156:26
    |
 LL |     let _ = x.into_iter().map(|Foo { foo, bar }| Foo { bar, foo });
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
 
 error: unnecessary map of the identity function
-  --> tests/ui/map_identity.rs:160:26
+  --> tests/ui/map_identity.rs:166:26
    |
 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/map_identity.rs:164:26
+  --> tests/ui/map_identity.rs:170:26
    |
 LL |     let _ = x.into_iter().map(|Foo2(foo, bar)| foo::Foo2(foo, bar));
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the call to `map`
 
-error: aborting due to 21 previous errors
+error: aborting due to 22 previous errors