Auto merge of rust-lang#5951 - ThibsG:FixMacroCloneOnRefPtr2076, r=ebroto

Fix incorrect suggestion when `clone_on_ref_ptr` is triggered in macros

In the lint `clone_on_ref_ptr`, if the `span` is in a macro, don't expand it for suggestion.

Fixes: rust-lang#2076

changelog: none

r? @ebroto

Author: bors

clippy_lints/src/methods/mod.rs

@@ -2150,18 +2150,15 @@ fn lint_clone_on_ref_ptr(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::
             return;
         };
 
+        let snippet = snippet_with_macro_callsite(cx, arg.span, "_");
+
         span_lint_and_sugg(
             cx,
             CLONE_ON_REF_PTR,
             expr.span,
             "using `.clone()` on a ref-counted pointer",
             "try this",
-            format!(
-                "{}::<{}>::clone(&{})",
-                caller_type,
-                subst.type_at(0),
-                snippet(cx, arg.span, "_")
-            ),
+            format!("{}::<{}>::clone(&{})", caller_type, subst.type_at(0), snippet),
             Applicability::Unspecified, // Sometimes unnecessary ::<_> after Rc/Arc/Weak
         );
     }

tests/ui/unnecessary_clone.rs

@@ -90,3 +90,21 @@ mod many_derefs {
         let _ = &encoded.clone();
     }
 }
+
+mod issue2076 {
+    use std::rc::Rc;
+
+    macro_rules! try_opt {
+        ($expr: expr) => {
+            match $expr {
+                Some(value) => value,
+                None => return None,
+            }
+        };
+    }
+
+    fn func() -> Option<Rc<u8>> {
+        let rc = Rc::new(42);
+        Some(try_opt!(Some(rc)).clone())
+    }
+}

tests/ui/unnecessary_clone.stderr

@@ -96,5 +96,11 @@ help: or try being explicit if you are sure, that you want to clone a reference
 LL |         let _ = &<&[u8]>::clone(encoded);
    |                  ^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 11 previous errors
+error: using `.clone()` on a ref-counted pointer
+  --> $DIR/unnecessary_clone.rs:108:14
+   |
+LL |         Some(try_opt!(Some(rc)).clone())
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `Rc::<u8>::clone(&try_opt!(Some(rc)))`
+
+error: aborting due to 12 previous errors