fix or_then_unwrap: suggestion preserves macro calls (#15483)

Before this change, the suggestion for
`Option.or(Some(vec![])).unwrap()` expanded the `vec!` macro which broke
the code, both in terms of readability, and because the expansion
references `$crate` which cannot be inlined.

changelog: [`or_then_unwrap`]: Preserve macro calls rather than
expanding them

Relates to #6851

Author: llogiq

clippy_lints/src/methods/or_then_unwrap.rs

@@ -62,7 +62,7 @@ fn get_content_if_ctor_matches(cx: &LateContext<'_>, expr: &Expr<'_>, item: Lang
     if let ExprKind::Call(some_expr, [arg]) = expr.kind
         && is_res_lang_ctor(cx, path_res(cx, some_expr), item)
     {
-        Some(arg.span)
+        Some(arg.span.source_callsite())
     } else {
         None
     }

tests/ui/or_then_unwrap.fixed

@@ -28,6 +28,12 @@ fn main() {
     //
     //~^^ or_then_unwrap
 
+    // Call with macro should preserve the macro call rather than expand it
+    let option: Option<Vec<&str>> = None;
+    let _ = option.unwrap_or(vec!["fallback"]); // should trigger lint
+    //
+    //~^^ or_then_unwrap
+
     // as part of a method chain
     let option: Option<&str> = None;
     let _ = option.map(|v| v).unwrap_or("fallback").to_string().chars(); // should trigger lint

tests/ui/or_then_unwrap.rs

@@ -28,6 +28,12 @@ fn main() {
     //
     //~^^ or_then_unwrap
 
+    // Call with macro should preserve the macro call rather than expand it
+    let option: Option<Vec<&str>> = None;
+    let _ = option.or(Some(vec!["fallback"])).unwrap(); // should trigger lint
+    //
+    //~^^ or_then_unwrap
+
     // as part of a method chain
     let option: Option<&str> = None;
     let _ = option.map(|v| v).or(Some("fallback")).unwrap().to_string().chars(); // should trigger lint

tests/ui/or_then_unwrap.stderr

@@ -14,10 +14,16 @@ LL |     let _ = result.or::<&str>(Ok("fallback")).unwrap(); // should trigger l
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `unwrap_or("fallback")`
 
 error: found `.or(Some(…)).unwrap()`
-  --> tests/ui/or_then_unwrap.rs:33:31
+  --> tests/ui/or_then_unwrap.rs:33:20
+   |
+LL |     let _ = option.or(Some(vec!["fallback"])).unwrap(); // should trigger lint
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `unwrap_or(vec!["fallback"])`
+
+error: found `.or(Some(…)).unwrap()`
+  --> tests/ui/or_then_unwrap.rs:39:31
    |
 LL |     let _ = option.map(|v| v).or(Some("fallback")).unwrap().to_string().chars(); // should trigger lint
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `unwrap_or("fallback")`
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors