option_map_unit_fn: Split into fixable/unfixable

Author: Manishearth

tests/ui/option_map_unit_fn_fixable.rs

@@ -71,29 +71,6 @@ fn option_map_unit_fn() {
     x.field.map(|value| { { plus_one(value + captured); } });
 
 
-    x.field.map(|ref value| { do_nothing(value + captured) });
-
-
-    x.field.map(|value| { do_nothing(value); do_nothing(value) });
-
-    x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
-
-    // Suggestion for the let block should be `{ ... }` as it's too difficult to build a
-    // proper suggestion for these cases
-    x.field.map(|value| {
-        do_nothing(value);
-        do_nothing(value)
-    });
-    x.field.map(|value| { do_nothing(value); do_nothing(value); });
-
-    // The following should suggest `if let Some(_X) ...` as it's difficult to generate a proper let variable name for them
-    Some(42).map(diverge);
-    "12".parse::<i32>().ok().map(diverge);
-    Some(plus_one(1)).map(do_nothing);
-
-    // Should suggest `if let Some(_y) ...` to not override the existing foo variable
-    let y = Some(42);
-    y.map(do_nothing);
-}
+    x.field.map(|ref value| { do_nothing(value + captured) });}
 
 fn main() {}

tests/ui/option_map_unit_fn_fixable.stderr

@@ -131,80 +131,10 @@ LL |     x.field.map(|value| { { plus_one(value + captured); } });
 error: called `map(f)` on an Option value where `f` is a unit closure
   --> $DIR/option_map_unit_fn_fixable.rs:74:5
    |
-LL |     x.field.map(|ref value| { do_nothing(value + captured) });
+LL |     x.field.map(|ref value| { do_nothing(value + captured) });}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
    |     |
    |     help: try this: `if let Some(ref value) = x.field { do_nothing(value + captured) }`
 
-error: called `map(f)` on an Option value where `f` is a unit closure
-  --> $DIR/option_map_unit_fn_fixable.rs:77:5
-   |
-LL |     x.field.map(|value| { do_nothing(value); do_nothing(value) });
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Some(value) = x.field { ... }`
-
-error: called `map(f)` on an Option value where `f` is a unit closure
-  --> $DIR/option_map_unit_fn_fixable.rs:79:5
-   |
-LL |     x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Some(value) = x.field { ... }`
-
-error: called `map(f)` on an Option value where `f` is a unit closure
-  --> $DIR/option_map_unit_fn_fixable.rs:83:5
-   |
-LL |        x.field.map(|value| {
-   |   _____^
-   |  |_____|
-   | ||
-LL | ||         do_nothing(value);
-LL | ||         do_nothing(value)
-LL | ||     });
-   | ||______^- help: try this: `if let Some(value) = x.field { ... }`
-   | |_______|
-   | 
-
-error: called `map(f)` on an Option value where `f` is a unit closure
-  --> $DIR/option_map_unit_fn_fixable.rs:87:5
-   |
-LL |     x.field.map(|value| { do_nothing(value); do_nothing(value); });
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Some(value) = x.field { ... }`
-
-error: called `map(f)` on an Option value where `f` is a unit function
-  --> $DIR/option_map_unit_fn_fixable.rs:90:5
-   |
-LL |     Some(42).map(diverge);
-   |     ^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Some(_) = Some(42) { diverge(...) }`
-
-error: called `map(f)` on an Option value where `f` is a unit function
-  --> $DIR/option_map_unit_fn_fixable.rs:91:5
-   |
-LL |     "12".parse::<i32>().ok().map(diverge);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Some(_) = "12".parse::<i32>().ok() { diverge(...) }`
-
-error: called `map(f)` on an Option value where `f` is a unit function
-  --> $DIR/option_map_unit_fn_fixable.rs:92:5
-   |
-LL |     Some(plus_one(1)).map(do_nothing);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Some(_) = Some(plus_one(1)) { do_nothing(...) }`
-
-error: called `map(f)` on an Option value where `f` is a unit function
-  --> $DIR/option_map_unit_fn_fixable.rs:96:5
-   |
-LL |     y.map(do_nothing);
-   |     ^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Some(_y) = y { do_nothing(...) }`
-
-error: aborting due to 25 previous errors
+error: aborting due to 17 previous errors
 

tests/ui/option_map_unit_fn_unfixable.rs

@@ -0,0 +1,39 @@
+#![warn(clippy::option_map_unit_fn)]
+#![allow(unused)]
+
+fn do_nothing<T>(_: T) {}
+
+fn diverge<T>(_: T) -> ! {
+    panic!()
+}
+
+fn plus_one(value: usize) -> usize {
+    value + 1
+}
+
+#[rustfmt::skip]
+fn option_map_unit_fn() {
+
+    x.field.map(|value| { do_nothing(value); do_nothing(value) });
+
+    x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
+
+    // Suggestion for the let block should be `{ ... }` as it's too difficult to build a
+    // proper suggestion for these cases
+    x.field.map(|value| {
+        do_nothing(value);
+        do_nothing(value)
+    });
+    x.field.map(|value| { do_nothing(value); do_nothing(value); });
+
+    // The following should suggest `if let Some(_X) ...` as it's difficult to generate a proper let variable name for them
+    Some(42).map(diverge);
+    "12".parse::<i32>().ok().map(diverge);
+    Some(plus_one(1)).map(do_nothing);
+
+    // Should suggest `if let Some(_y) ...` to not override the existing foo variable
+    let y = Some(42);
+    y.map(do_nothing);
+}
+
+fn main() {}

tests/ui/option_map_unit_fn_unfixable.stderr

@@ -0,0 +1,27 @@
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/option_map_unit_fn_unfixable.rs:17:5
+   |
+LL |     x.field.map(|value| { do_nothing(value); do_nothing(value) });
+   |     ^ not found in this scope
+
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/option_map_unit_fn_unfixable.rs:19:5
+   |
+LL |     x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
+   |     ^ not found in this scope
+
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/option_map_unit_fn_unfixable.rs:23:5
+   |
+LL |     x.field.map(|value| {
+   |     ^ not found in this scope
+
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/option_map_unit_fn_unfixable.rs:27:5
+   |
+LL |     x.field.map(|value| { do_nothing(value); do_nothing(value); });
+   |     ^ not found in this scope
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0425`.

tests/ui/result_map_unit_fn_fixable.rs

@@ -74,29 +74,6 @@ fn result_map_unit_fn() {
 
 
     x.field.map(|ref value| { do_nothing(value + captured) });
-
-
-    x.field.map(|value| { do_nothing(value); do_nothing(value) });
-
-    x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
-
-    // Suggestion for the let block should be `{ ... }` as it's too difficult to build a
-    // proper suggestion for these cases
-    x.field.map(|value| {
-        do_nothing(value);
-        do_nothing(value)
-    });
-    x.field.map(|value| { do_nothing(value); do_nothing(value); });
-
-    // The following should suggest `if let Ok(_X) ...` as it's difficult to generate a proper let variable name for them
-    let res: Result<!, usize> = Ok(42).map(diverge);
-    "12".parse::<i32>().map(diverge);
-
-    let res: Result<(), usize> = Ok(plus_one(1)).map(do_nothing);
-
-    // Should suggest `if let Ok(_y) ...` to not override the existing foo variable
-    let y: Result<usize, usize> = Ok(42);
-    y.map(do_nothing);
 }
 
 fn main() {}

tests/ui/result_map_unit_fn_fixable.stderr

@@ -136,59 +136,5 @@ LL |     x.field.map(|ref value| { do_nothing(value + captured) });
    |     |
    |     help: try this: `if let Ok(ref value) = x.field { do_nothing(value + captured) }`
 
-error: called `map(f)` on an Result value where `f` is a unit closure
-  --> $DIR/result_map_unit_fn_fixable.rs:79:5
-   |
-LL |     x.field.map(|value| { do_nothing(value); do_nothing(value) });
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Ok(value) = x.field { ... }`
-
-error: called `map(f)` on an Result value where `f` is a unit closure
-  --> $DIR/result_map_unit_fn_fixable.rs:81:5
-   |
-LL |     x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Ok(value) = x.field { ... }`
-
-error: called `map(f)` on an Result value where `f` is a unit closure
-  --> $DIR/result_map_unit_fn_fixable.rs:85:5
-   |
-LL |        x.field.map(|value| {
-   |   _____^
-   |  |_____|
-   | ||
-LL | ||         do_nothing(value);
-LL | ||         do_nothing(value)
-LL | ||     });
-   | ||______^- help: try this: `if let Ok(value) = x.field { ... }`
-   | |_______|
-   | 
-
-error: called `map(f)` on an Result value where `f` is a unit closure
-  --> $DIR/result_map_unit_fn_fixable.rs:89:5
-   |
-LL |     x.field.map(|value| { do_nothing(value); do_nothing(value); });
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Ok(value) = x.field { ... }`
-
-error: called `map(f)` on an Result value where `f` is a unit function
-  --> $DIR/result_map_unit_fn_fixable.rs:93:5
-   |
-LL |     "12".parse::<i32>().map(diverge);
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Ok(_) = "12".parse::<i32>() { diverge(...) }`
-
-error: called `map(f)` on an Result value where `f` is a unit function
-  --> $DIR/result_map_unit_fn_fixable.rs:99:5
-   |
-LL |     y.map(do_nothing);
-   |     ^^^^^^^^^^^^^^^^^-
-   |     |
-   |     help: try this: `if let Ok(_y) = y { do_nothing(...) }`
-
-error: aborting due to 23 previous errors
+error: aborting due to 17 previous errors
 

tests/ui/result_map_unit_fn_unfixable.rs

@@ -0,0 +1,40 @@
+#![feature(never_type)]
+#![warn(clippy::result_map_unit_fn)]
+#![allow(unused)]
+
+fn do_nothing<T>(_: T) {}
+
+fn diverge<T>(_: T) -> ! {
+    panic!()
+}
+
+fn plus_one(value: usize) -> usize {
+    value + 1
+}
+
+#[rustfmt::skip]
+fn result_map_unit_fn() {
+    x.field.map(|value| { do_nothing(value); do_nothing(value) });
+
+    x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
+
+    // Suggestion for the let block should be `{ ... }` as it's too difficult to build a
+    // proper suggestion for these cases
+    x.field.map(|value| {
+        do_nothing(value);
+        do_nothing(value)
+    });
+    x.field.map(|value| { do_nothing(value); do_nothing(value); });
+
+    // The following should suggest `if let Ok(_X) ...` as it's difficult to generate a proper let variable name for them
+    let res: Result<!, usize> = Ok(42).map(diverge);
+    "12".parse::<i32>().map(diverge);
+
+    let res: Result<(), usize> = Ok(plus_one(1)).map(do_nothing);
+
+    // Should suggest `if let Ok(_y) ...` to not override the existing foo variable
+    let y: Result<usize, usize> = Ok(42);
+    y.map(do_nothing);
+}
+
+fn main() {}

tests/ui/result_map_unit_fn_unfixable.stderr

@@ -0,0 +1,27 @@
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/result_map_unit_fn_unfixable.rs:17:5
+   |
+LL |     x.field.map(|value| { do_nothing(value); do_nothing(value) });
+   |     ^ not found in this scope
+
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/result_map_unit_fn_unfixable.rs:19:5
+   |
+LL |     x.field.map(|value| if value > 0 { do_nothing(value); do_nothing(value) });
+   |     ^ not found in this scope
+
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/result_map_unit_fn_unfixable.rs:23:5
+   |
+LL |     x.field.map(|value| {
+   |     ^ not found in this scope
+
+error[E0425]: cannot find value `x` in this scope
+  --> $DIR/result_map_unit_fn_unfixable.rs:27:5
+   |
+LL |     x.field.map(|value| { do_nothing(value); do_nothing(value); });
+   |     ^ not found in this scope
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0425`.