update docs, simplify arg->param map, dont lint on chain

3 files changed, 29 insertions, 11 deletions

diff --git a/tests/ui/explicit_into_iter_fn_arg.fixed b/tests/ui/explicit_into_iter_fn_arg.fixed
index 219b60bd051..9d778faf8e0 100644
--- a/tests/ui/explicit_into_iter_fn_arg.fixed
+++ b/tests/ui/explicit_into_iter_fn_arg.fixed
@@ -1,6 +1,6 @@
 //@run-rustfix
 
-#![allow(unused)]
+#![allow(unused, clippy::useless_conversion)]
 #![warn(clippy::explicit_into_iter_fn_arg)]
 
 fn a<T>(_: T) {}
@@ -11,7 +11,6 @@ where
     T: IntoIterator<Item = i32>,
 {
 }
-fn e<T: IntoIterator<Item = i32>>(_: T) {}
 fn f(_: std::vec::IntoIter<i32>) {}
 
 fn main() {
@@ -19,6 +18,16 @@ fn main() {
     b(vec![1, 2]);
     c(vec![1, 2]);
     d(vec![1, 2]);
-    e([&1, &2, &3].into_iter().cloned());
-    f(vec![1, 2].into_iter());
+    b([&1, &2, &3].into_iter().cloned());
+
+    // Don't lint chained `.into_iter().into_iter()` calls. Covered by useless_conversion.
+    b(vec![1, 2].into_iter().into_iter());
+    b(vec![1, 2].into_iter().into_iter().into_iter());
+
+    macro_rules! macro_generated {
+        () => {
+            vec![1, 2].into_iter()
+        };
+    }
+    b(macro_generated!());
 }
diff --git a/tests/ui/explicit_into_iter_fn_arg.rs b/tests/ui/explicit_into_iter_fn_arg.rs
index 358f4bc661d..1e051fd06ec 100644
--- a/tests/ui/explicit_into_iter_fn_arg.rs
+++ b/tests/ui/explicit_into_iter_fn_arg.rs
@@ -1,6 +1,6 @@
 //@run-rustfix
 
-#![allow(unused)]
+#![allow(unused, clippy::useless_conversion)]
 #![warn(clippy::explicit_into_iter_fn_arg)]
 
 fn a<T>(_: T) {}
@@ -11,7 +11,6 @@ where
     T: IntoIterator<Item = i32>,
 {
 }
-fn e<T: IntoIterator<Item = i32>>(_: T) {}
 fn f(_: std::vec::IntoIter<i32>) {}
 
 fn main() {
@@ -19,6 +18,16 @@ fn main() {
     b(vec![1, 2].into_iter());
     c(vec![1, 2].into_iter());
     d(vec![1, 2].into_iter());
-    e([&1, &2, &3].into_iter().cloned());
-    f(vec![1, 2].into_iter());
+    b([&1, &2, &3].into_iter().cloned());
+
+    // Don't lint chained `.into_iter().into_iter()` calls. Covered by useless_conversion.
+    b(vec![1, 2].into_iter().into_iter());
+    b(vec![1, 2].into_iter().into_iter().into_iter());
+
+    macro_rules! macro_generated {
+        () => {
+            vec![1, 2].into_iter()
+        };
+    }
+    b(macro_generated!());
 }
diff --git a/tests/ui/explicit_into_iter_fn_arg.stderr b/tests/ui/explicit_into_iter_fn_arg.stderr
index a0bd81c21ea..14b95fb097a 100644
--- a/tests/ui/explicit_into_iter_fn_arg.stderr
+++ b/tests/ui/explicit_into_iter_fn_arg.stderr
@@ -1,5 +1,5 @@
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/explicit_into_iter_fn_arg.rs:19:7
+  --> $DIR/explicit_into_iter_fn_arg.rs:18:7
    |
 LL |     b(vec![1, 2].into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `.into_iter()`: `vec![1, 2]`
@@ -12,7 +12,7 @@ LL | fn b<T: IntoIterator<Item = i32>>(_: T) {}
    = note: `-D clippy::explicit-into-iter-fn-arg` implied by `-D warnings`
 
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/explicit_into_iter_fn_arg.rs:20:7
+  --> $DIR/explicit_into_iter_fn_arg.rs:19:7
    |
 LL |     c(vec![1, 2].into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `.into_iter()`: `vec![1, 2]`
@@ -24,7 +24,7 @@ LL | fn c(_: impl IntoIterator<Item = i32>) {}
    |              ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/explicit_into_iter_fn_arg.rs:21:7
+  --> $DIR/explicit_into_iter_fn_arg.rs:20:7
    |
 LL |     d(vec![1, 2].into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `.into_iter()`: `vec![1, 2]`