Add more test cases

Co-authored-by: Samuel Tardieu <sam@rfc1149.net>

Author: Yusuf Raji

tests/ui/single_option_map.rs

@@ -29,6 +29,17 @@ fn manipulate_opt(opt_i: Option<i32>) -> Option<i32> {
     opt_i.map(manipulate)
 }
 
+// No lint: maps other than the receiver
+fn map_not_arg(arg: Option<u32>) -> Option<u32> {
+    maps_static_option().map(|_| arg.unwrap())
+}
+
+// No lint: wrapper function with η-expanded form
+#[allow(clippy::redundant_closure)]
+fn manipulate_opt_explicit(opt_i: Option<i32>) -> Option<i32> {
+    opt_i.map(|x| manipulate(x))
+}
+
 fn main() {
     let answer = Some(42u32);
     let h_result = h(answer);

tests/ui/single_option_map.stderr

@@ -2,6 +2,7 @@ error: `fn` that only maps over argument
   --> tests/ui/single_option_map.rs:8:1
    |
 LL | / fn h(arg: Option<u32>) -> Option<u32> {
+LL | |
 LL | |     arg.map(|x| x * 2)
 LL | | }
    | |_^
@@ -11,14 +12,25 @@ LL | | }
    = help: to override `-D warnings` add `#[allow(clippy::single_option_map)]`
 
 error: `fn` that only maps over argument
-  --> tests/ui/single_option_map.rs:12:1
+  --> tests/ui/single_option_map.rs:13:1
    |
 LL | / fn j(arg: Option<u64>) -> Option<u64> {
+LL | |
 LL | |     arg.map(|x| x * 2)
 LL | | }
    | |_^
    |
    = help: move the `.map` to the caller or to an `_opt` function
 
-error: aborting due to 2 previous errors
+error: `fn` that only maps over argument
+  --> tests/ui/single_option_map.rs:39:1
+   |
+LL | / fn manipulate_opt_explicit(opt_i: Option<i32>) -> Option<i32> {
+LL | |     opt_i.map(|x| manipulate(x))
+LL | | }
+   | |_^
+   |
+   = help: move the `.map` to the caller or to an `_opt` function
+
+error: aborting due to 3 previous errors