What Rust's syntax really reminds me of is Algol 68, or BLISS, both of them being these old procedural languages where everything is an expression. The "loop { ... break expr; ... }" thing reminds me of BLISS's "exitloop expr" construct.
There's so many programming languages (low barrier to create) that there's a ton of overlap and evolutionary changes/similarities between them. I was thinking of perl's "do { x } while foo" style constructs in this particular case.
I am incredibly amused that I got downvoted to -1 for mentioning perl though. People here are Weird.
