[core] Fix GCC8's new -Wcatch-value warnings

Polymorphic types shouldn't be caught by value, as the warning message says. Catch them by constant reference instead.

3 files changed, 3 insertions, 3 deletions

diff --git a/test/storage/offline_database.test.cpp b/test/storage/offline_database.test.cpp
index 36b71bc4b4..10343ec305 100644
--- a/test/storage/offline_database.test.cpp
+++ b/test/storage/offline_database.test.cpp
@@ -631,7 +631,7 @@ TEST(OfflineDatabase, BatchInsertionMapboxTileCountExceeded) {
     try {
         db.putRegionResources(region.getID(), resources, status);
         EXPECT_FALSE(true);
-    } catch (MapboxTileLimitExceededException) {
+    } catch (const MapboxTileLimitExceededException&) {
         // Expected
     }
     
diff --git a/test/style/style.test.cpp b/test/style/style.test.cpp
index 9bdab37ac6..f2055c88f8 100644
--- a/test/style/style.test.cpp
+++ b/test/style/style.test.cpp
@@ -65,7 +65,7 @@ TEST(Style, DuplicateSource) {
     try {
         style.addSource(std::make_unique<VectorSource>("sourceId", "mapbox://mapbox.mapbox-terrain-v2"));
         FAIL() << "Should not have been allowed to add a duplicate source id";
-    } catch (std::runtime_error) {
+    } catch (const std::runtime_error&) {
         // Expected
     }
 }
diff --git a/test/style/style_layer.test.cpp b/test/style/style_layer.test.cpp
index 624ed088c3..61516a2de9 100644
--- a/test/style/style_layer.test.cpp
+++ b/test/style/style_layer.test.cpp
@@ -285,7 +285,7 @@ TEST(Layer, DuplicateLayer) {
     try {
         style.addLayer(std::make_unique<LineLayer>("line", "unusedsource"));
         FAIL() << "Should not have been allowed to add a duplicate layer id";
-    } catch (const std::runtime_error e) {
+    } catch (const std::runtime_error& e) {
         // Expected
         ASSERT_STREQ("Layer line already exists", e.what());
     }