Fix suggestion to slice if scrutinee is a `Result` or `Option`

3 files changed, 75 insertions, 0 deletions

diff --git a/src/test/ui/typeck/issue-91328.fixed b/src/test/ui/typeck/issue-91328.fixed
new file mode 100644
index 00000000000..48dc26718da
--- /dev/null
+++ b/src/test/ui/typeck/issue-91328.fixed
@@ -0,0 +1,27 @@
+// Regression test for issue #91328.
+
+// run-rustfix
+
+#![allow(dead_code)]
+
+fn foo(r: Result<Vec<i32>, i32>) -> i32 {
+    match r.as_deref() {
+    //~^ HELP: consider using `as_deref` here
+        Ok([a, b]) => a + b,
+        //~^ ERROR: expected an array or slice
+        //~| NOTE: pattern cannot match with input type
+        _ => 42,
+    }
+}
+
+fn bar(o: Option<Vec<i32>>) -> i32 {
+    match o.as_deref() {
+    //~^ HELP: consider using `as_deref` here
+        Some([a, b]) => a + b,
+        //~^ ERROR: expected an array or slice
+        //~| NOTE: pattern cannot match with input type
+        _ => 42,
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/typeck/issue-91328.rs b/src/test/ui/typeck/issue-91328.rs
new file mode 100644
index 00000000000..de5deb95349
--- /dev/null
+++ b/src/test/ui/typeck/issue-91328.rs
@@ -0,0 +1,27 @@
+// Regression test for issue #91328.
+
+// run-rustfix
+
+#![allow(dead_code)]
+
+fn foo(r: Result<Vec<i32>, i32>) -> i32 {
+    match r {
+    //~^ HELP: consider using `as_deref` here
+        Ok([a, b]) => a + b,
+        //~^ ERROR: expected an array or slice
+        //~| NOTE: pattern cannot match with input type
+        _ => 42,
+    }
+}
+
+fn bar(o: Option<Vec<i32>>) -> i32 {
+    match o {
+    //~^ HELP: consider using `as_deref` here
+        Some([a, b]) => a + b,
+        //~^ ERROR: expected an array or slice
+        //~| NOTE: pattern cannot match with input type
+        _ => 42,
+    }
+}
+
+fn main() {}
diff --git a/src/test/ui/typeck/issue-91328.stderr b/src/test/ui/typeck/issue-91328.stderr
new file mode 100644
index 00000000000..4a9ddb2b927
--- /dev/null
+++ b/src/test/ui/typeck/issue-91328.stderr
@@ -0,0 +1,21 @@
+error[E0529]: expected an array or slice, found `Vec<i32>`
+  --> $DIR/issue-91328.rs:10:12
+   |
+LL |     match r {
+   |           - help: consider using `as_deref` here: `r.as_deref()`
+LL |
+LL |         Ok([a, b]) => a + b,
+   |            ^^^^^^ pattern cannot match with input type `Vec<i32>`
+
+error[E0529]: expected an array or slice, found `Vec<i32>`
+  --> $DIR/issue-91328.rs:20:14
+   |
+LL |     match o {
+   |           - help: consider using `as_deref` here: `o.as_deref()`
+LL |
+LL |         Some([a, b]) => a + b,
+   |              ^^^^^^ pattern cannot match with input type `Vec<i32>`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0529`.