Raw Dedupe Works

Author: stephen-lazaro

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -684,6 +684,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
             let span = init.span(self.body);
             if !span.is_dummy() {
                 spans.push(span);
+                println!("ADDED: {:?}", span);
             }
         }
 
@@ -779,7 +780,12 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, '_, 'infcx, 'tcx> {
             }
         }
         if !shown {
+            spans.dedup();
             for sp in &spans {
+                println!("span {:?}", sp);
+                println!("span {:?}", *sp < span);
+                println!("COMP: {:?}", span);
+                println!("COMP: {:?}", !sp.overlaps(span));
                 if *sp < span && !sp.overlaps(span) {
                     err.span_label(*sp, "binding initialized here in some conditions");
                 }

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())
+}

tests/ui/duplicate-label-E0381-issue-129274.stderr

@@ -0,0 +1,15 @@
+error[E0381]: used binding `blah` is possibly-uninitialized
+  --> $DIR/issue-129274.rs:9:33
+   |
+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 |             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`.