useless_conversion: don't lint if ty param has multiple bounds

tests/ui/useless_conversion.fixed

@@ -151,6 +151,8 @@ fn main() {
     let _ = s3;
     let s4: Foo<'a'> = Foo;
     let _ = vec![s4, s4, s4].into_iter();
+
+    issue11300::bar();
 }
 
 #[allow(dead_code)]
@@ -196,6 +198,22 @@ fn explicit_into_iter_fn_arg() {
     b(macro_generated!());
 }
 
+mod issue11300 {
+    pub fn foo<I>(i: I)
+    where
+        I: IntoIterator<Item = i32> + ExactSizeIterator,
+    {
+        assert_eq!(i.len(), 3);
+    }
+
+    pub fn bar() {
+        // This should not trigger the lint:
+        // `[i32, 3]` does not satisfy the `ExactSizeIterator` bound, so the into_iter call cannot be
+        // removed and is not useless.
+        foo([1, 2, 3].into_iter());
+    }
+}
+
 #[derive(Copy, Clone)]
 struct Foo<const C: char>;
 

tests/ui/useless_conversion.rs

@@ -151,6 +151,8 @@ fn main() {
     let _ = Foo::<'a'>::from(s3);
     let s4: Foo<'a'> = Foo;
     let _ = vec![s4, s4, s4].into_iter().into_iter();
+
+    issue11300::bar();
 }
 
 #[allow(dead_code)]
@@ -196,6 +198,22 @@ fn explicit_into_iter_fn_arg() {
     b(macro_generated!());
 }
 
+mod issue11300 {
+    pub fn foo<I>(i: I)
+    where
+        I: IntoIterator<Item = i32> + ExactSizeIterator,
+    {
+        assert_eq!(i.len(), 3);
+    }
+
+    pub fn bar() {
+        // This should not trigger the lint:
+        // `[i32, 3]` does not satisfy the `ExactSizeIterator` bound, so the into_iter call cannot be
+        // removed and is not useless.
+        foo([1, 2, 3].into_iter());
+    }
+}
+
 #[derive(Copy, Clone)]
 struct Foo<const C: char>;
 

tests/ui/useless_conversion.stderr

@@ -119,61 +119,61 @@ LL |     let _ = vec![s4, s4, s4].into_iter().into_iter();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing `.into_iter()`: `vec![s4, s4, s4].into_iter()`
 
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/useless_conversion.rs:183:7
+  --> $DIR/useless_conversion.rs:185:7
    |
 LL |     b(vec![1, 2].into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^ help: consider removing the `.into_iter()`: `vec![1, 2]`
    |
 note: this parameter accepts any `IntoIterator`, so you don't need to call `.into_iter()`
-  --> $DIR/useless_conversion.rs:173:13
+  --> $DIR/useless_conversion.rs:175:13
    |
 LL |     fn b<T: IntoIterator<Item = i32>>(_: T) {}
    |             ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/useless_conversion.rs:184:7
+  --> $DIR/useless_conversion.rs:186:7
    |
 LL |     c(vec![1, 2].into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^ help: consider removing the `.into_iter()`: `vec![1, 2]`
    |
 note: this parameter accepts any `IntoIterator`, so you don't need to call `.into_iter()`
-  --> $DIR/useless_conversion.rs:174:18
+  --> $DIR/useless_conversion.rs:176:18
    |
 LL |     fn c(_: impl IntoIterator<Item = i32>) {}
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/useless_conversion.rs:185:7
+  --> $DIR/useless_conversion.rs:187:7
    |
 LL |     d(vec![1, 2].into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^ help: consider removing the `.into_iter()`: `vec![1, 2]`
    |
 note: this parameter accepts any `IntoIterator`, so you don't need to call `.into_iter()`
-  --> $DIR/useless_conversion.rs:177:12
+  --> $DIR/useless_conversion.rs:179:12
    |
 LL |         T: IntoIterator<Item = i32>,
    |            ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/useless_conversion.rs:188:7
+  --> $DIR/useless_conversion.rs:190:7
    |
 LL |     b(vec![1, 2].into_iter().into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing the `.into_iter()`s: `vec![1, 2]`
    |
 note: this parameter accepts any `IntoIterator`, so you don't need to call `.into_iter()`
-  --> $DIR/useless_conversion.rs:173:13
+  --> $DIR/useless_conversion.rs:175:13
    |
 LL |     fn b<T: IntoIterator<Item = i32>>(_: T) {}
    |             ^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit call to `.into_iter()` in function argument accepting `IntoIterator`
-  --> $DIR/useless_conversion.rs:189:7
+  --> $DIR/useless_conversion.rs:191:7
    |
 LL |     b(vec![1, 2].into_iter().into_iter().into_iter());
    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing the `.into_iter()`s: `vec![1, 2]`
    |
 note: this parameter accepts any `IntoIterator`, so you don't need to call `.into_iter()`
-  --> $DIR/useless_conversion.rs:173:13
+  --> $DIR/useless_conversion.rs:175:13
    |
 LL |     fn b<T: IntoIterator<Item = i32>>(_: T) {}
    |             ^^^^^^^^^^^^^^^^^^^^^^^^