Revert "or_fn_call: ignore nullary associated const fns"

This reverts commit 7a66e6502d.

clippy_lints/src/utils/mod.rs

@@ -893,7 +893,7 @@ pub fn is_ctor_or_promotable_const_function(cx: &LateContext<'_>, expr: &Expr<'_
             return match res {
                 def::Res::Def(DefKind::Variant | DefKind::Ctor(..), ..) => true,
                 // FIXME: check the constness of the arguments, see https://github.com/rust-lang/rust-clippy/pull/5682#issuecomment-638681210
-                def::Res::Def(DefKind::Fn | DefKind::AssocFn, def_id) if has_no_arguments(cx, def_id) => {
+                def::Res::Def(DefKind::Fn, def_id) if has_no_arguments(cx, def_id) => {
                     const_eval::is_const_fn(cx.tcx, def_id)
                 },
                 def::Res::Def(_, def_id) => cx.tcx.is_promotable_const_fn(def_id),

tests/ui/or_fun_call.fixed

@@ -58,6 +58,12 @@ fn or_fun_call() {
     let without_default = Some(Foo);
     without_default.unwrap_or_else(Foo::new);
 
+    let mut map = HashMap::<u64, String>::new();
+    map.entry(42).or_insert_with(String::new);
+
+    let mut btree = BTreeMap::<u64, String>::new();
+    btree.entry(42).or_insert_with(String::new);
+
     let stringy = Some(String::from(""));
     let _ = stringy.unwrap_or_else(|| "".to_owned());
 
@@ -116,17 +122,6 @@ pub fn skip_const_fn_with_no_args() {
         Some(42)
     }
     let _ = None.or(foo());
-
-    // See issue #5693.
-    let mut map = std::collections::HashMap::new();
-    map.insert(1, vec![1]);
-    map.entry(1).or_insert(vec![]);
-
-    let mut map = HashMap::<u64, String>::new();
-    map.entry(42).or_insert(String::new());
-
-    let mut btree = BTreeMap::<u64, String>::new();
-    btree.entry(42).or_insert(String::new());
 }
 
 fn main() {}

tests/ui/or_fun_call.rs

@@ -58,6 +58,12 @@ fn or_fun_call() {
     let without_default = Some(Foo);
     without_default.unwrap_or(Foo::new());
 
+    let mut map = HashMap::<u64, String>::new();
+    map.entry(42).or_insert(String::new());
+
+    let mut btree = BTreeMap::<u64, String>::new();
+    btree.entry(42).or_insert(String::new());
+
     let stringy = Some(String::from(""));
     let _ = stringy.unwrap_or("".to_owned());
 
@@ -116,17 +122,6 @@ pub fn skip_const_fn_with_no_args() {
         Some(42)
     }
     let _ = None.or(foo());
-
-    // See issue #5693.
-    let mut map = std::collections::HashMap::new();
-    map.insert(1, vec![1]);
-    map.entry(1).or_insert(vec![]);
-
-    let mut map = HashMap::<u64, String>::new();
-    map.entry(42).or_insert(String::new());
-
-    let mut btree = BTreeMap::<u64, String>::new();
-    btree.entry(42).or_insert(String::new());
 }
 
 fn main() {}

tests/ui/or_fun_call.stderr

@@ -60,23 +60,35 @@ error: use of `unwrap_or` followed by a function call
 LL |     without_default.unwrap_or(Foo::new());
    |                     ^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(Foo::new)`
 
+error: use of `or_insert` followed by a function call
+  --> $DIR/or_fun_call.rs:62:19
+   |
+LL |     map.entry(42).or_insert(String::new());
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(String::new)`
+
+error: use of `or_insert` followed by a function call
+  --> $DIR/or_fun_call.rs:65:21
+   |
+LL |     btree.entry(42).or_insert(String::new());
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(String::new)`
+
 error: use of `unwrap_or` followed by a function call
-  --> $DIR/or_fun_call.rs:62:21
+  --> $DIR/or_fun_call.rs:68:21
    |
 LL |     let _ = stringy.unwrap_or("".to_owned());
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| "".to_owned())`
 
 error: use of `or` followed by a function call
-  --> $DIR/or_fun_call.rs:87:35
+  --> $DIR/or_fun_call.rs:93:35
    |
 LL |     let _ = Some("a".to_string()).or(Some("b".to_string()));
    |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_else(|| Some("b".to_string()))`
 
 error: use of `or` followed by a function call
-  --> $DIR/or_fun_call.rs:91:10
+  --> $DIR/or_fun_call.rs:97:10
    |
 LL |         .or(Some(Bar(b, Duration::from_secs(2))));
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `or_else(|| Some(Bar(b, Duration::from_secs(2))))`
 
-error: aborting due to 13 previous errors
+error: aborting due to 15 previous errors