Deduplicate Spans in Uninitialized Check

Prevents reporting labels or diagnostics on spans that are produced
multiple times.

2 files changed, 28 insertions, 0 deletions

diff --git a/tests/ui/duplicate-label-E0381-issue-129274.rs b/tests/ui/duplicate-label-E0381-issue-129274.rs
new file mode 100644
index 00000000000..b2156e630c8
--- /dev/null
+++ b/tests/ui/duplicate-label-E0381-issue-129274.rs
@@ -0,0 +1,13 @@
+fn main() {
+    fn test() {
+        loop {
+            let blah: Option<String>;
+            if true {
+                blah = Some("".to_string());
+            }
+            if let Some(blah) = blah.as_ref() { //~ ERROR E0381
+            }
+        }
+    }
+    println!("{:?}", test())
+}
diff --git a/tests/ui/duplicate-label-E0381-issue-129274.stderr b/tests/ui/duplicate-label-E0381-issue-129274.stderr
new file mode 100644
index 00000000000..7f8bddb17c5
--- /dev/null
+++ b/tests/ui/duplicate-label-E0381-issue-129274.stderr
@@ -0,0 +1,15 @@
+error[E0381]: used binding `blah` is possibly-uninitialized
+  --> $DIR/duplicate-label-E0381-issue-129274.rs:8:33
+   |
+LL |             let blah: Option<String>;
+   |                 ---- binding declared here but left uninitialized
+LL |             if true {
+LL |                 blah = Some("".to_string());
+   |                 ---- binding initialized here in some conditions
+LL |             }
+LL |             if let Some(blah) = blah.as_ref() {
+   |                                 ^^^^ `blah` used here but it is possibly-uninitialized
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0381`.