Variable scoping sometimes inconsistent when debugging

[wesleywiser]

I tried this code:

fn main() {
  let a = 5;
  let b = 6;
  let c = a + b;
  println!("Hello world {c}");
}

I expected to see this happen:
When setting a breakpoint on the line 2, no variables should be in scope. Then stepping forward one line shows just a in scope, etc.

Instead, this happened:
Both a and b were in scope but "unavailable". c was correctly not in scope until the println!().

Meta

rustc --version --verbose:

rustc 1.70.0 (90c541806 2023-05-31)
binary: rustc
commit-hash: 90c541806f23a127002de5b4038be731ba1458ca
commit-date: 2023-05-31
host: x86_64-pc-windows-msvc
release: 1.70.0
LLVM version: 16.0.2

This may be a Windows specific debugging issue.