1 files changed, 14 insertions, 1 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index 0e495973a01..75692540c03 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -1,3 +1,4 @@
+use std::collections::hash_map::Entry;
 use std::ops::Range;
 
 use rustc_data_structures::fx::FxHashMap;
@@ -447,6 +448,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         }
 
         let mut per_local = IndexVec::from_elem(vec![], &self.mir.local_decls);
+        let mut params_seen: FxHashMap<_, Bx::DIVariable> = Default::default();
         for var in &self.mir.var_debug_info {
             let dbg_scope_and_span = if full_debug_info {
                 self.adjusted_span_and_dbg_scope(var.source_info)
@@ -491,7 +493,18 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     VariableKind::LocalVariable
                 };
 
-                self.cx.create_dbg_var(var.name, var_ty, dbg_scope, var_kind, span)
+                if let VariableKind::ArgumentVariable(arg_index) = var_kind {
+                    match params_seen.entry((dbg_scope, arg_index)) {
+                        Entry::Occupied(o) => o.get().clone(),
+                        Entry::Vacant(v) => v
+                            .insert(
+                                self.cx.create_dbg_var(var.name, var_ty, dbg_scope, var_kind, span),
+                            )
+                            .clone(),
+                    }
+                } else {
+                    self.cx.create_dbg_var(var.name, var_ty, dbg_scope, var_kind, span)
+                }
             });
 
             let fragment = if let Some(ref fragment) = var.composite {