rustfmt is not idempotent over some blocks that consist of a series of empty statements finished by an expression #4748
Description
Describe the bug
rustfmt is not idempotent over some blocks that consist of a series of empty statements finished by an expression. The first pass strips the empty statements and the second pass applies any applicable transformation to the block such as unwrapping the expression in it or rearranging it into a single line.
To Reproduce
Example input:
fn foo(x: Option<i32>) -> i32 {
let y = {
;
x
};
match y {
Some(y) => {
;
;
y
}
None => 0,
}
}Calling rustfmt once results in
fn foo(x: Option<i32>) -> i32 {
let y = {
x
};
match y {
Some(y) => {
y
}
None => 0,
}
}Calling rustfmt on the previous output then results in
fn foo(x: Option<i32>) -> i32 {
let y = { x };
match y {
Some(y) => y,
None => 0,
}
}Expected behavior
rustfmt should return the output of the second pass in the first pass.
Meta
- rustfmt version: rustfmt 1.4.36-nightly (7de6968 2021-02-07)
- From where did you install rustfmt?: rustup
- How do you run rustfmt?: via rust-analyzer in vscode, but this was tested with
rustfmttoo