Add new lint to detect unnecessarily wrapped value

tests/ui/unnecessary_wrap.fixed

@@ -0,0 +1,47 @@
+// run-rustfix
+#![warn(clippy::unnecessary_wrap)]
+#![allow(clippy::no_effect)]
+#![allow(clippy::needless_return)]
+#![allow(clippy::if_same_then_else)]
+
+// should be linted
+fn func1(a: bool, b: bool) -> Option<i32> {
+    if a && b {
+        return Some(42);
+    }
+    if a {
+        Some(-1);
+        Some(2)
+    } else {
+        return Some(1337);
+    }
+}
+
+// public fns should not be linted
+pub fn func2(a: bool) -> Option<i32> {
+    if a {
+        Some(1)
+    } else {
+        Some(1)
+    }
+}
+
+// should not be linted
+fn func3(a: bool) -> Option<i32> {
+    if a {
+        Some(1)
+    } else {
+        None
+    }
+}
+
+// should be linted
+fn func4() -> Option<i32> {
+    1
+}
+
+fn main() {
+    // method calls are not linted
+    func1(true, true);
+    func2(true);
+}

tests/ui/unnecessary_wrap.rs

@@ -0,0 +1,47 @@
+// run-rustfix
+#![warn(clippy::unnecessary_wrap)]
+#![allow(clippy::no_effect)]
+#![allow(clippy::needless_return)]
+#![allow(clippy::if_same_then_else)]
+
+// should be linted
+fn func1(a: bool, b: bool) -> Option<i32> {
+    if a && b {
+        return Some(42);
+    }
+    if a {
+        Some(-1);
+        Some(2)
+    } else {
+        return Some(1337);
+    }
+}
+
+// public fns should not be linted
+pub fn func2(a: bool) -> Option<i32> {
+    if a {
+        Some(1)
+    } else {
+        Some(1)
+    }
+}
+
+// should not be linted
+fn func3(a: bool) -> Option<i32> {
+    if a {
+        Some(1)
+    } else {
+        None
+    }
+}
+
+// should be linted
+fn func4() -> Option<i32> {
+    Some(1)
+}
+
+fn main() {
+    // method calls are not linted
+    func1(true, true);
+    func2(true);
+}

tests/ui/unnecessary_wrap.stderr

@@ -0,0 +1,34 @@
+error: this function unnecessarily wrapping data
+  --> $DIR/unnecessary_wrap.rs:8:1
+   |
+LL | / fn func1(a: bool, b: bool) -> Option<i32> {
+LL | |     if a && b {
+LL | |         return Some(42);
+LL | |     }
+...  |
+LL | |     }
+LL | | }
+   | |_^
+   |
+   = note: `-D clippy::unnecessary-wrap` implied by `-D warnings`
+help: factor this out to
+   |
+LL |         return 42;
+LL |     }
+LL |     if a {
+LL |         Some(-1);
+LL |         2
+LL |     } else {
+ ...
+
+error: this function unnecessarily wrapping data
+  --> $DIR/unnecessary_wrap.rs:39:1
+   |
+LL | / fn func4() -> Option<i32> {
+LL | |     Some(1)
+   | |     ------- help: factor this out to: `1`
+LL | | }
+   | |_^
+
+error: aborting due to 2 previous errors
+