diff --git a/src/Sema.zig b/src/Sema.zig
index 82acbab9e5..860d9d63ac 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -18910,7 +18910,7 @@ fn resolvePeerTypes(
                         }
 
                         const chosen_set_ty = err_set_ty orelse chosen_ty.errorUnionSet();
-                        const candidate_set_ty = chosen_ty.errorUnionSet();
+                        const candidate_set_ty = candidate_ty.errorUnionSet();
 
                         if (.ok == try sema.coerceInMemoryAllowedErrorSets(block, chosen_set_ty, candidate_set_ty, src, src)) {
                             err_set_ty = chosen_set_ty;
diff --git a/test/behavior/error.zig b/test/behavior/error.zig
index b3503051fb..93d76443ae 100644
--- a/test/behavior/error.zig
+++ b/test/behavior/error.zig
@@ -626,3 +626,11 @@ test "inferred error set equality" {
     try expect(BarError == BarError);
     try expect(BazError == BazError);
 }
+
+test "peer type resolution of two different error unions" {
+    const a: error{B}!void = {};
+    const b: error{A}!void = {};
+    var cond = true;
+    const err = if (cond) a else b;
+    try err;
+}