Fix compilation warnings and re-enable werror=yes on Travis

Fix -Wunused-variable, -Wunused-but-set-variable and -Wswitch warnings
raised by GCC 8 and 9.

Fix -Wunused-function, -Wunused-private-field and
-Wtautological-constant-out-of-range-compare raised by Clang.

Fix MSVC 2019 warning C4804 (unsafe use of type 'bool' in comparison
operation).

GCC -Wcpp warnings/Clang -W#warnings (`#warning`) are no longer raising
errors and will thus not abort compilation with `werror=yes`.

Treat glslang headers are system headers to avoid raising warnings.

Re-enables us to build with `werror=yes` on Linux and macOS, thus
catching warnings that would be introduced by new code.

Fixes #36132.

1 files changed, 4 insertions, 4 deletions

diff --git a/servers/visual/rasterizer_rd/rasterizer_storage_rd.cpp b/servers/visual/rasterizer_rd/rasterizer_storage_rd.cpp
index 9f6b1a2b35..09767cb5a9 100644
--- a/servers/visual/rasterizer_rd/rasterizer_storage_rd.cpp
+++ b/servers/visual/rasterizer_rd/rasterizer_storage_rd.cpp
@@ -1944,7 +1944,7 @@ int RasterizerStorageRD::mesh_get_blend_shape_count(RID p_mesh) const {
 void RasterizerStorageRD::mesh_set_blend_shape_mode(RID p_mesh, VS::BlendShapeMode p_mode) {
 	Mesh *mesh = mesh_owner.getornull(p_mesh);
 	ERR_FAIL_COND(!mesh);
-	ERR_FAIL_INDEX(p_mode, 2);
+	ERR_FAIL_INDEX((int)p_mode, 2);
 
 	mesh->blend_shape_mode = p_mode;
 }
@@ -2636,7 +2636,7 @@ void RasterizerStorageRD::multimesh_instance_set_custom_data(RID p_multimesh, in
 	MultiMesh *multimesh = multimesh_owner.getornull(p_multimesh);
 	ERR_FAIL_COND(!multimesh);
 	ERR_FAIL_INDEX(p_index, multimesh->instances);
-	ERR_FAIL_INDEX(p_index, !multimesh->uses_custom_data);
+	ERR_FAIL_COND(!multimesh->uses_custom_data);
 
 	_multimesh_make_local(multimesh);
 
@@ -2723,7 +2723,7 @@ Color RasterizerStorageRD::multimesh_instance_get_color(RID p_multimesh, int p_i
 	MultiMesh *multimesh = multimesh_owner.getornull(p_multimesh);
 	ERR_FAIL_COND_V(!multimesh, Color());
 	ERR_FAIL_INDEX_V(p_index, multimesh->instances, Color());
-	ERR_FAIL_INDEX_V(p_index, !multimesh->uses_colors, Color());
+	ERR_FAIL_COND_V(!multimesh->uses_colors, Color());
 
 	_multimesh_make_local(multimesh);
 
@@ -2746,7 +2746,7 @@ Color RasterizerStorageRD::multimesh_instance_get_custom_data(RID p_multimesh, i
 	MultiMesh *multimesh = multimesh_owner.getornull(p_multimesh);
 	ERR_FAIL_COND_V(!multimesh, Color());
 	ERR_FAIL_INDEX_V(p_index, multimesh->instances, Color());
-	ERR_FAIL_INDEX_V(p_index, !multimesh->uses_custom_data, Color());
+	ERR_FAIL_COND_V(!multimesh->uses_custom_data, Color());
 
 	_multimesh_make_local(multimesh);