--- a/mojoshader_opengl.c	Wed May 29 16:52:12 2019 -0400
+++ b/mojoshader_opengl.c	Wed May 29 16:53:06 2019 -0400
@@ -386,6 +386,7 @@
         return GL_FRAGMENT_SHADER;
 
     // !!! FIXME: geometry shaders?
+    assert(0 && "Unknown GLSL shader type!");
     return GL_NONE;
 } // glsl_shader_type