diff --git a/src/db/db/dbDeepEdges.cc b/src/db/db/dbDeepEdges.cc
index c1ca6f78b..93dd301d1 100644
--- a/src/db/db/dbDeepEdges.cc
+++ b/src/db/db/dbDeepEdges.cc
@@ -1200,8 +1200,9 @@ RegionDelegate *DeepEdges::extended (coord_type ext_b, coord_type ext_e, coord_t
           out = & to_commit [c->cell_index ()][v->first];
         }
 
+        PolygonRefToShapesGenerator prgen (&layout, out);
         for (db::Shapes::shape_iterator si = c->shapes (edges.layer ()).begin (db::ShapeIterator::Edges); ! si.at_end (); ++si) {
-          out->insert (extended_edge (si->edge ().transformed (v->first), ext_b, ext_e, ext_o, ext_i).transformed (v->first.inverted ()));
+          prgen.put (extended_edge (si->edge ().transformed (v->first), ext_b, ext_e, ext_o, ext_i).transformed (v->first.inverted ()));
         }
 
       }
diff --git a/src/drc/unit_tests/drcSimpleTests.cc b/src/drc/unit_tests/drcSimpleTests.cc
index 2ee8dd3a2..c3969acbe 100644
--- a/src/drc/unit_tests/drcSimpleTests.cc
+++ b/src/drc/unit_tests/drcSimpleTests.cc
@@ -1338,3 +1338,12 @@ TEST(56d_angle_classes)
   run_test (_this, "56", true);
 }
 
+TEST(57_issue_1190)
+{
+  run_test (_this, "57", false);
+}
+
+TEST(57d_issue_1190)
+{
+  run_test (_this, "57", true);
+}
diff --git a/testdata/drc/drcSimpleTests_57.drc b/testdata/drc/drcSimpleTests_57.drc
new file mode 100644
index 000000000..e65afe876
--- /dev/null
+++ b/testdata/drc/drcSimpleTests_57.drc
@@ -0,0 +1,18 @@
+
+source $drc_test_source
+target $drc_test_target
+
+if $drc_test_deep
+  deep
+end
+
+l1 = input(1, 0)
+
+l1.output(1, 0)
+
+l1e = l1.edges
+l1e.with_angle(ortho).extended_out(1.dbu).merged.output(100, 0)
+l1e.with_angle(diagonal_only).extended_in(1.dbu).merged.output(101, 0)
+l1e.with_angle(diagonal).extended(1.dbu, 2.dbu, 3.dbu, 4.dbu).merged.output(102, 0)
+
+
diff --git a/testdata/drc/drcSimpleTests_57.gds b/testdata/drc/drcSimpleTests_57.gds
new file mode 100644
index 000000000..a9ab615db
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diff --git a/testdata/drc/drcSimpleTests_au57.gds b/testdata/drc/drcSimpleTests_au57.gds
new file mode 100644
index 000000000..43381ea0d
Binary files /dev/null and b/testdata/drc/drcSimpleTests_au57.gds differ
diff --git a/testdata/drc/drcSimpleTests_au57d.gds b/testdata/drc/drcSimpleTests_au57d.gds
new file mode 100644
index 000000000..3a0e2a359
Binary files /dev/null and b/testdata/drc/drcSimpleTests_au57d.gds differ