1 files changed, 14 insertions, 0 deletions
diff --git a/mesalib/src/mesa/main/shaderapi.c b/mesalib/src/mesa/main/shaderapi.c
index 2590abe7e..be6946798 100644
--- a/mesalib/src/mesa/main/shaderapi.c
+++ b/mesalib/src/mesa/main/shaderapi.c
@@ -207,6 +207,8 @@ attach_shader(struct gl_context *ctx, GLuint program, GLuint shader)
    struct gl_shader *sh;
    GLuint i, n;
 
+   const bool same_type_disallowed = _mesa_is_gles(ctx);
+
    shProg = _mesa_lookup_shader_program_err(ctx, program, "glAttachShader");
    if (!shProg)
       return;
@@ -227,6 +229,18 @@ attach_shader(struct gl_context *ctx, GLuint program, GLuint shader)
           */
          _mesa_error(ctx, GL_INVALID_OPERATION, "glAttachShader");
          return;
+      } else if (same_type_disallowed &&
+                 shProg->Shaders[i]->Type == sh->Type) {
+        /* Shader with the same type is already attached to this program,
+         * OpenGL ES 2.0 and 3.0 specs say:
+         *
+         *      "Multiple shader objects of the same type may not be attached
+         *      to a single program object. [...] The error INVALID_OPERATION
+         *      is generated if [...] another shader object of the same type
+         *      as shader is already attached to program."
+         */
+         _mesa_error(ctx, GL_INVALID_OPERATION, "glAttachShader");
+         return;
       }
    }