panic_in_result_fn: Extend to also check usages of [debug_]assert* macros

Also, the macro-finding logic has been moved to the util module, for
use by future lints.

tests/ui/panic_in_result_fn.stderr

@@ -1,4 +1,4 @@
-error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
   --> $DIR/panic_in_result_fn.rs:7:5
    |
 LL | /     fn result_with_panic() -> Result<bool, String> // should emit lint
@@ -8,7 +8,7 @@ LL | |     }
    | |_____^
    |
    = note: `-D clippy::panic-in-result-fn` implied by `-D warnings`
-   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
   --> $DIR/panic_in_result_fn.rs:9:9
    |
@@ -16,7 +16,7 @@ LL |         panic!("error");
    |         ^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
   --> $DIR/panic_in_result_fn.rs:12:5
    |
 LL | /     fn result_with_unimplemented() -> Result<bool, String> // should emit lint
@@ -25,7 +25,7 @@ LL | |         unimplemented!();
 LL | |     }
    | |_____^
    |
-   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
   --> $DIR/panic_in_result_fn.rs:14:9
    |
@@ -33,7 +33,7 @@ LL |         unimplemented!();
    |         ^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
   --> $DIR/panic_in_result_fn.rs:17:5
    |
 LL | /     fn result_with_unreachable() -> Result<bool, String> // should emit lint
@@ -42,7 +42,7 @@ LL | |         unreachable!();
 LL | |     }
    | |_____^
    |
-   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
   --> $DIR/panic_in_result_fn.rs:19:9
    |
@@ -50,7 +50,7 @@ LL |         unreachable!();
    |         ^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
   --> $DIR/panic_in_result_fn.rs:22:5
    |
 LL | /     fn result_with_todo() -> Result<bool, String> // should emit lint
@@ -59,7 +59,7 @@ LL | |         todo!("Finish this");
 LL | |     }
    | |_____^
    |
-   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
   --> $DIR/panic_in_result_fn.rs:24:9
    |
@@ -67,7 +67,7 @@ LL |         todo!("Finish this");
    |         ^^^^^^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
   --> $DIR/panic_in_result_fn.rs:53:1
    |
 LL | / fn function_result_with_panic() -> Result<bool, String> // should emit lint
@@ -76,7 +76,7 @@ LL | |     panic!("error");
 LL | | }
    | |_^
    |
-   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
   --> $DIR/panic_in_result_fn.rs:55:5
    |
@@ -84,7 +84,7 @@ LL |     panic!("error");
    |     ^^^^^^^^^^^^^^^^
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
   --> $DIR/panic_in_result_fn.rs:68:1
    |
 LL | / fn main() -> Result<(), String> {
@@ -93,7 +93,7 @@ LL | |     Ok(())
 LL | | }
    | |_^
    |
-   = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
 note: return Err() instead of panicking
   --> $DIR/panic_in_result_fn.rs:69:5
    |

tests/ui/panic_in_result_fn_assertions.rs

@@ -0,0 +1,48 @@
+#![warn(clippy::panic_in_result_fn)]
+#![allow(clippy::unnecessary_wraps)]
+
+struct A;
+
+impl A {
+    fn result_with_assert_with_message(x: i32) -> Result<bool, String> // should emit lint
+    {
+        assert!(x == 5, "wrong argument");
+        Ok(true)
+    }
+
+    fn result_with_assert_eq(x: i32) -> Result<bool, String> // should emit lint
+    {
+        assert_eq!(x, 5);
+        Ok(true)
+    }
+
+    fn result_with_assert_ne(x: i32) -> Result<bool, String> // should emit lint
+    {
+        assert_ne!(x, 1);
+        Ok(true)
+    }
+
+    fn other_with_assert_with_message(x: i32) // should not emit lint
+    {
+        assert!(x == 5, "wrong argument");
+    }
+
+    fn other_with_assert_eq(x: i32) // should not emit lint
+    {
+        assert_eq!(x, 5);
+    }
+
+    fn other_with_assert_ne(x: i32) // should not emit lint
+    {
+        assert_ne!(x, 1);
+    }
+
+    fn result_without_banned_functions() -> Result<bool, String> // should not emit lint
+    {
+        let assert = "assert!";
+        println!("No {}", assert);
+        Ok(true)
+    }
+}
+
+fn main() {}

tests/ui/panic_in_result_fn_assertions.stderr

@@ -0,0 +1,57 @@
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
+  --> $DIR/panic_in_result_fn_assertions.rs:7:5
+   |
+LL | /     fn result_with_assert_with_message(x: i32) -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         assert!(x == 5, "wrong argument");
+LL | |         Ok(true)
+LL | |     }
+   | |_____^
+   |
+   = note: `-D clippy::panic-in-result-fn` implied by `-D warnings`
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result_fn_assertions.rs:9:9
+   |
+LL |         assert!(x == 5, "wrong argument");
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
+  --> $DIR/panic_in_result_fn_assertions.rs:13:5
+   |
+LL | /     fn result_with_assert_eq(x: i32) -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         assert_eq!(x, 5);
+LL | |         Ok(true)
+LL | |     }
+   | |_____^
+   |
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result_fn_assertions.rs:15:9
+   |
+LL |         assert_eq!(x, 5);
+   |         ^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
+  --> $DIR/panic_in_result_fn_assertions.rs:19:5
+   |
+LL | /     fn result_with_assert_ne(x: i32) -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         assert_ne!(x, 1);
+LL | |         Ok(true)
+LL | |     }
+   | |_____^
+   |
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result_fn_assertions.rs:21:9
+   |
+LL |         assert_ne!(x, 1);
+   |         ^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+

tests/ui/panic_in_result_fn_debug_assertions.rs

@@ -0,0 +1,48 @@
+#![warn(clippy::panic_in_result_fn)]
+#![allow(clippy::unnecessary_wraps)]
+
+struct A;
+
+impl A {
+    fn result_with_debug_assert_with_message(x: i32) -> Result<bool, String> // should emit lint
+    {
+        debug_assert!(x == 5, "wrong argument");
+        Ok(true)
+    }
+
+    fn result_with_debug_assert_eq(x: i32) -> Result<bool, String> // should emit lint
+    {
+        debug_assert_eq!(x, 5);
+        Ok(true)
+    }
+
+    fn result_with_debug_assert_ne(x: i32) -> Result<bool, String> // should emit lint
+    {
+        debug_assert_ne!(x, 1);
+        Ok(true)
+    }
+
+    fn other_with_debug_assert_with_message(x: i32) // should not emit lint
+    {
+        debug_assert!(x == 5, "wrong argument");
+    }
+
+    fn other_with_debug_assert_eq(x: i32) // should not emit lint
+    {
+        debug_assert_eq!(x, 5);
+    }
+
+    fn other_with_debug_assert_ne(x: i32) // should not emit lint
+    {
+        debug_assert_ne!(x, 1);
+    }
+
+    fn result_without_banned_functions() -> Result<bool, String> // should not emit lint
+    {
+        let debug_assert = "debug_assert!";
+        println!("No {}", debug_assert);
+        Ok(true)
+    }
+}
+
+fn main() {}

tests/ui/panic_in_result_fn_debug_assertions.stderr

@@ -0,0 +1,57 @@
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
+  --> $DIR/panic_in_result_fn_debug_assertions.rs:7:5
+   |
+LL | /     fn result_with_debug_assert_with_message(x: i32) -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         debug_assert!(x == 5, "wrong argument");
+LL | |         Ok(true)
+LL | |     }
+   | |_____^
+   |
+   = note: `-D clippy::panic-in-result-fn` implied by `-D warnings`
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result_fn_debug_assertions.rs:9:9
+   |
+LL |         debug_assert!(x == 5, "wrong argument");
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
+  --> $DIR/panic_in_result_fn_debug_assertions.rs:13:5
+   |
+LL | /     fn result_with_debug_assert_eq(x: i32) -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         debug_assert_eq!(x, 5);
+LL | |         Ok(true)
+LL | |     }
+   | |_____^
+   |
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result_fn_debug_assertions.rs:15:9
+   |
+LL |         debug_assert_eq!(x, 5);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: used `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertion in a function that returns `Result`
+  --> $DIR/panic_in_result_fn_debug_assertions.rs:19:5
+   |
+LL | /     fn result_with_debug_assert_ne(x: i32) -> Result<bool, String> // should emit lint
+LL | |     {
+LL | |         debug_assert_ne!(x, 1);
+LL | |         Ok(true)
+LL | |     }
+   | |_____^
+   |
+   = help: `unimplemented!()`, `unreachable!()`, `todo!()`, `panic!()` or assertions should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing
+note: return Err() instead of panicking
+  --> $DIR/panic_in_result_fn_debug_assertions.rs:21:9
+   |
+LL |         debug_assert_ne!(x, 1);
+   |         ^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 3 previous errors
+