Lint manual_unwrap_or_default for Result as well

Author: lochetti

clippy_lints/src/manual_unwrap_or_default.rs

@@ -57,7 +57,8 @@ fn get_some<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'tcx>) -> Option<HirId> {
         // Since it comes from a pattern binding, we need to get the parent to actually match
         // against it.
         && let Some(def_id) = cx.tcx.opt_parent(def_id)
-        && cx.tcx.lang_items().get(LangItem::OptionSome) == Some(def_id)
+        && (cx.tcx.lang_items().get(LangItem::OptionSome) == Some(def_id)
+        || cx.tcx.lang_items().get(LangItem::ResultOk) == Some(def_id))
     {
         let mut bindings = Vec::new();
         pat.each_binding(|_, id, _, _| bindings.push(id));
@@ -80,6 +81,14 @@ fn get_none<'tcx>(cx: &LateContext<'tcx>, arm: &Arm<'tcx>) -> Option<&'tcx Expr<
         && cx.tcx.lang_items().get(LangItem::OptionNone) == Some(def_id)
     {
         Some(arm.body)
+    } else if let PatKind::TupleStruct(QPath::Resolved(_, path), _, _)= arm.pat.kind
+        && let Some(def_id) = path.res.opt_def_id()
+        // Since it comes from a pattern binding, we need to get the parent to actually match
+        // against it.
+        && let Some(def_id) = cx.tcx.opt_parent(def_id)
+        && cx.tcx.lang_items().get(LangItem::ResultErr) == Some(def_id)
+    {
+        Some(arm.body)
     } else if let PatKind::Wild = arm.pat.kind {
         // We consider that the `Some` check will filter it out if it's not right.
         Some(arm.body)

tests/ui/manual_unwrap_or_default.fixed

@@ -26,6 +26,12 @@ fn main() {
         Some(x) => x,
         None => &[],
     };
+
+    let x: Result<String, i64> = Ok(String::new());
+    x.unwrap_or_default();
+
+    let x: Result<String, i64> = Ok(String::new());
+    x.unwrap_or_default();
 }
 
 // Issue #12531

tests/ui/manual_unwrap_or_default.rs

@@ -47,6 +47,21 @@ fn main() {
         Some(x) => x,
         None => &[],
     };
+
+    let x: Result<String, i64> = Ok(String::new());
+    match x {
+        //~^ ERROR: match can be simplified with `.unwrap_or_default()`
+        Ok(v) => v,
+        Err(_) => String::new(),
+    };
+
+    let x: Result<String, i64> = Ok(String::new());
+    if let Ok(v) = x {
+        //~^ ERROR: if let can be simplified with `.unwrap_or_default()`
+        v
+    } else {
+        String::new()
+    };
 }
 
 // Issue #12531

tests/ui/manual_unwrap_or_default.stderr

@@ -53,7 +53,28 @@ LL | |     };
    | |_____^ help: replace it with: `x.unwrap_or_default()`
 
 error: match can be simplified with `.unwrap_or_default()`
-  --> tests/ui/manual_unwrap_or_default.rs:56:20
+  --> tests/ui/manual_unwrap_or_default.rs:52:5
+   |
+LL | /     match x {
+LL | |
+LL | |         Ok(v) => v,
+LL | |         Err(_) => String::new(),
+LL | |     };
+   | |_____^ help: replace it with: `x.unwrap_or_default()`
+
+error: if let can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default.rs:59:5
+   |
+LL | /     if let Ok(v) = x {
+LL | |
+LL | |         v
+LL | |     } else {
+LL | |         String::new()
+LL | |     };
+   | |_____^ help: replace it with: `x.unwrap_or_default()`
+
+error: match can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default.rs:71:20
    |
 LL |           Some(_) => match *b {
    |  ____________________^
@@ -62,5 +83,5 @@ LL | |             _ => 0,
 LL | |         },
    | |_________^ help: replace it with: `(*b).unwrap_or_default()`
 
-error: aborting due to 6 previous errors
+error: aborting due to 8 previous errors