or_fun_call: fix suggestion for or_insert(vec![])

Applies for `std::collections::hash_map::Entry` and `std::collections::btree_map::Entry`

Example:
Previously, for the following code:
`let _ = hash_map.entry("test".to_owned()).or_insert(vec![]);`
clippy would suggest to use:
`or_insert_with(vec![])`, which causes a compiler error (E0277).

Now clippy suggests:
`or_insert_with(Vec::new)`

Author: mgacek8

clippy_lints/src/methods/mod.rs

@@ -2005,12 +2005,26 @@ fn lint_or_fun_call<'tcx>(
             if poss.contains(&name);
 
             then {
+                let macro_expanded_snipped;
                 let sugg: Cow<'_, str> = {
                     let (snippet_span, use_lambda) = match (fn_has_arguments, fun_span) {
                         (false, Some(fun_span)) => (fun_span, false),
                         _ => (arg.span, true),
                     };
-                    let snippet = snippet_with_macro_callsite(cx, snippet_span, "..");
+                    let snippet = {
+                        let not_macro_argument_snippet = snippet_with_macro_callsite(cx, snippet_span, "..");
+                        if not_macro_argument_snippet == "vec![]" {
+                            macro_expanded_snipped = snippet(cx, snippet_span, "..");
+                            match macro_expanded_snipped.strip_prefix("$crate::vec::") {
+                                Some(stripped) => Cow::from(stripped),
+                                None => macro_expanded_snipped
+                            }
+                        }
+                        else {
+                            not_macro_argument_snippet
+                        }
+                    };
+
                     if use_lambda {
                         let l_arg = if fn_has_arguments { "_" } else { "" };
                         format!("|{}| {}", l_arg, snippet).into()

tests/ui/or_fun_call.fixed

@@ -62,9 +62,15 @@ fn or_fun_call() {
     let mut map = HashMap::<u64, String>::new();
     map.entry(42).or_insert_with(String::new);
 
+    let mut map_vec = HashMap::<u64, Vec<i32>>::new();
+    map_vec.entry(42).or_insert_with(Vec::new);
+
     let mut btree = BTreeMap::<u64, String>::new();
     btree.entry(42).or_insert_with(String::new);
 
+    let mut btree_vec = BTreeMap::<u64, Vec<i32>>::new();
+    btree_vec.entry(42).or_insert_with(Vec::new);
+
     let stringy = Some(String::from(""));
     let _ = stringy.unwrap_or_else(|| "".to_owned());
 

tests/ui/or_fun_call.rs

@@ -62,9 +62,15 @@ fn or_fun_call() {
     let mut map = HashMap::<u64, String>::new();
     map.entry(42).or_insert(String::new());
 
+    let mut map_vec = HashMap::<u64, Vec<i32>>::new();
+    map_vec.entry(42).or_insert(vec![]);
+
     let mut btree = BTreeMap::<u64, String>::new();
     btree.entry(42).or_insert(String::new());
 
+    let mut btree_vec = BTreeMap::<u64, Vec<i32>>::new();
+    btree_vec.entry(42).or_insert(vec![]);
+
     let stringy = Some(String::from(""));
     let _ = stringy.unwrap_or("".to_owned());
 

tests/ui/or_fun_call.stderr

@@ -67,40 +67,52 @@ 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:66:21
+  --> $DIR/or_fun_call.rs:66:23
+   |
+LL |     map_vec.entry(42).or_insert(vec![]);
+   |                       ^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(Vec::new)`
+
+error: use of `or_insert` followed by a function call
+  --> $DIR/or_fun_call.rs:69:21
    |
 LL |     btree.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:72:25
+   |
+LL |     btree_vec.entry(42).or_insert(vec![]);
+   |                         ^^^^^^^^^^^^^^^^^ help: try this: `or_insert_with(Vec::new)`
+
 error: use of `unwrap_or` followed by a function call
-  --> $DIR/or_fun_call.rs:69:21
+  --> $DIR/or_fun_call.rs:75:21
    |
 LL |     let _ = stringy.unwrap_or("".to_owned());
    |                     ^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| "".to_owned())`
 
 error: use of `unwrap_or` followed by a function call
-  --> $DIR/or_fun_call.rs:77:21
+  --> $DIR/or_fun_call.rs:83:21
    |
 LL |     let _ = Some(1).unwrap_or(map[&1]);
    |                     ^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| map[&1])`
 
 error: use of `unwrap_or` followed by a function call
-  --> $DIR/or_fun_call.rs:79:21
+  --> $DIR/or_fun_call.rs:85:21
    |
 LL |     let _ = Some(1).unwrap_or(map[&1]);
    |                     ^^^^^^^^^^^^^^^^^^ help: try this: `unwrap_or_else(|| map[&1])`
 
 error: use of `or` followed by a function call
-  --> $DIR/or_fun_call.rs:103:35
+  --> $DIR/or_fun_call.rs:109:35
    |
 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:107:10
+  --> $DIR/or_fun_call.rs:113:10
    |
 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 17 previous errors
+error: aborting due to 19 previous errors