What version of ripgrep are you using?

[I] ➜ rg --version
ripgrep 12.1.1
-SIMD -AVX (compiled)
+SIMD +AVX (runtime)

How did you install ripgrep?

homebrew

What operating system are you using ripgrep on?

osx mojave

Give a high level description of the bug.

Syntax info says:

USAGE:

    rg [OPTIONS] PATTERN [PATH ...]

So this should work:

[I] ➜ echo test | rg -M 900 st
error: The following required arguments were not provided:
    <PATTERN>

but it doesn't, one has to use:

[I] ➜ echo test | rg st -M 900
test

IOW, options before the pattern should be allowed, but it appears that at least the -M option only works if after the pattern.