Upgrade map_flatten to complexity

clippy_lints/src/lib.register_all.rs

@@ -159,6 +159,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(methods::MANUAL_SPLIT_ONCE),
     LintId::of(methods::MANUAL_STR_REPEAT),
     LintId::of(methods::MAP_COLLECT_RESULT_UNIT),
+    LintId::of(methods::MAP_FLATTEN),
     LintId::of(methods::MAP_IDENTITY),
     LintId::of(methods::NEEDLESS_SPLITN),
     LintId::of(methods::NEW_RET_NO_SELF),

clippy_lints/src/lib.register_complexity.rs

@@ -41,6 +41,7 @@ store.register_group(true, "clippy::complexity", Some("clippy_complexity"), vec!
     LintId::of(methods::MANUAL_FILTER_MAP),
     LintId::of(methods::MANUAL_FIND_MAP),
     LintId::of(methods::MANUAL_SPLIT_ONCE),
+    LintId::of(methods::MAP_FLATTEN),
     LintId::of(methods::MAP_IDENTITY),
     LintId::of(methods::NEEDLESS_SPLITN),
     LintId::of(methods::OPTION_AS_REF_DEREF),

clippy_lints/src/lib.register_pedantic.rs

@@ -63,7 +63,6 @@ store.register_group(true, "clippy::pedantic", Some("clippy_pedantic"), vec![
     LintId::of(methods::FROM_ITER_INSTEAD_OF_COLLECT),
     LintId::of(methods::IMPLICIT_CLONE),
     LintId::of(methods::INEFFICIENT_TO_STRING),
-    LintId::of(methods::MAP_FLATTEN),
     LintId::of(methods::MAP_UNWRAP_OR),
     LintId::of(misc::FLOAT_CMP),
     LintId::of(misc::USED_UNDERSCORE_BINDING),

clippy_lints/src/methods/mod.rs

@@ -543,7 +543,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.31.0"]
     pub MAP_FLATTEN,
-    pedantic,
+    complexity,
     "using combinations of `flatten` and `map` which can usually be written as a single method call"
 }
 

tests/ui/option_env_unwrap.rs

@@ -1,5 +1,6 @@
 // aux-build:macro_rules.rs
 #![warn(clippy::option_env_unwrap)]
+#![allow(clippy::map_flatten)]
 
 #[macro_use]
 extern crate macro_rules;

tests/ui/option_env_unwrap.stderr

@@ -1,5 +1,5 @@
 error: this will panic at run-time if the environment variable doesn't exist at compile-time
-  --> $DIR/option_env_unwrap.rs:17:13
+  --> $DIR/option_env_unwrap.rs:18:13
    |
 LL |     let _ = option_env!("PATH").unwrap();
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -8,15 +8,15 @@ LL |     let _ = option_env!("PATH").unwrap();
    = help: consider using the `env!` macro instead
 
 error: this will panic at run-time if the environment variable doesn't exist at compile-time
-  --> $DIR/option_env_unwrap.rs:18:13
+  --> $DIR/option_env_unwrap.rs:19:13
    |
 LL |     let _ = option_env!("PATH").expect("environment variable PATH isn't set");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider using the `env!` macro instead
 
 error: this will panic at run-time if the environment variable doesn't exist at compile-time
-  --> $DIR/option_env_unwrap.rs:9:9
+  --> $DIR/option_env_unwrap.rs:10:9
    |
 LL |         option_env!($env).unwrap()
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -28,7 +28,7 @@ LL |     let _ = option_env_unwrap!("PATH");
    = note: this error originates in the macro `option_env_unwrap` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: this will panic at run-time if the environment variable doesn't exist at compile-time
-  --> $DIR/option_env_unwrap.rs:12:9
+  --> $DIR/option_env_unwrap.rs:13:9
    |
 LL |         option_env!($env).expect($message)
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -40,7 +40,7 @@ LL |     let _ = option_env_unwrap!("PATH", "environment variable PATH isn't set
    = note: this error originates in the macro `option_env_unwrap` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: this will panic at run-time if the environment variable doesn't exist at compile-time
-  --> $DIR/option_env_unwrap.rs:21:13
+  --> $DIR/option_env_unwrap.rs:22:13
    |
 LL |     let _ = option_env_unwrap_external!("PATH");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -49,7 +49,7 @@ LL |     let _ = option_env_unwrap_external!("PATH");
    = note: this error originates in the macro `option_env_unwrap_external` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: this will panic at run-time if the environment variable doesn't exist at compile-time
-  --> $DIR/option_env_unwrap.rs:22:13
+  --> $DIR/option_env_unwrap.rs:23:13
    |
 LL |     let _ = option_env_unwrap_external!("PATH", "environment variable PATH isn't set");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

tests/ui/option_filter_map.fixed

@@ -1,8 +1,6 @@
-#![warn(clippy::option_filter_map)]
 // run-rustfix
-fn odds_out(x: i32) -> Option<i32> {
-    if x % 2 == 0 { Some(x) } else { None }
-}
+#![warn(clippy::option_filter_map)]
+#![allow(clippy::map_flatten)]
 
 fn main() {
     let _ = Some(Some(1)).flatten();
@@ -21,3 +19,7 @@ fn main() {
         .map(odds_out)
         .flatten();
 }
+
+fn odds_out(x: i32) -> Option<i32> {
+    if x % 2 == 0 { Some(x) } else { None }
+}

tests/ui/option_filter_map.rs

@@ -1,8 +1,6 @@
-#![warn(clippy::option_filter_map)]
 // run-rustfix
-fn odds_out(x: i32) -> Option<i32> {
-    if x % 2 == 0 { Some(x) } else { None }
-}
+#![warn(clippy::option_filter_map)]
+#![allow(clippy::map_flatten)]
 
 fn main() {
     let _ = Some(Some(1)).filter(Option::is_some).map(Option::unwrap);
@@ -23,3 +21,7 @@ fn main() {
         .filter(|o| o.is_some())
         .map(|o| o.unwrap());
 }
+
+fn odds_out(x: i32) -> Option<i32> {
+    if x % 2 == 0 { Some(x) } else { None }
+}

tests/ui/option_filter_map.stderr

@@ -1,51 +1,51 @@
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:8:27
+  --> $DIR/option_filter_map.rs:6:27
    |
 LL |     let _ = Some(Some(1)).filter(Option::is_some).map(Option::unwrap);
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `flatten` instead: `flatten()`
    |
    = note: `-D clippy::option-filter-map` implied by `-D warnings`
 
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:9:27
+  --> $DIR/option_filter_map.rs:7:27
    |
 LL |     let _ = Some(Some(1)).filter(|o| o.is_some()).map(|o| o.unwrap());
    |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `flatten` instead: `flatten()`
 
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:10:35
+  --> $DIR/option_filter_map.rs:8:35
    |
 LL |     let _ = Some(1).map(odds_out).filter(Option::is_some).map(Option::unwrap);
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `flatten` instead: `flatten()`
 
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:11:35
+  --> $DIR/option_filter_map.rs:9:35
    |
 LL |     let _ = Some(1).map(odds_out).filter(|o| o.is_some()).map(|o| o.unwrap());
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `flatten` instead: `flatten()`
 
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:13:39
+  --> $DIR/option_filter_map.rs:11:39
    |
 LL |     let _ = vec![Some(1)].into_iter().filter(Option::is_some).map(Option::unwrap);
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `flatten` instead: `flatten()`
 
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:14:39
+  --> $DIR/option_filter_map.rs:12:39
    |
 LL |     let _ = vec![Some(1)].into_iter().filter(|o| o.is_some()).map(|o| o.unwrap());
    |                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `flatten` instead: `flatten()`
 
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:18:10
+  --> $DIR/option_filter_map.rs:16:10
    |
 LL |           .filter(Option::is_some)
    |  __________^
 LL | |         .map(Option::unwrap);
    | |____________________________^ help: consider using `flatten` instead: `flatten()`
 
 error: `filter` for `Some` followed by `unwrap`
-  --> $DIR/option_filter_map.rs:23:10
+  --> $DIR/option_filter_map.rs:21:10
    |
 LL |           .filter(|o| o.is_some())
    |  __________^