The compiler error message about cyclic dependencies between modules should indicate that it's a cyclic dependency between module *ctors* or *dtors*, otherwise users could be misled into trying to fix the non-existent problem of cyclic imports.
See also: https://issues.dlang.org/show_bug.cgi?id=5053 (Note: this is NOT the same bug; the latter refers to the error message emitted by druntime at runtime. This present bug is concerned with the *compiler* error message.)
Comment #1 by hsteoh — 2018-12-06T18:54:11Z
Correction: actually, there is no such error message in the compiler. This is a druntime bug: the wording of the error message should be made clearer.