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hack around non-terminating macro expansion

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This commit is contained in:
Aleksey Kladov 2019-03-16 15:45:21 +03:00
parent b2a6c17362
commit d4449945a0
1 changed files with 14 additions and 0 deletions
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14
crates/ra_mbe/src/mbe_expander.rs
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@ -155,7 +155,14 @@ fn match_lhs(pattern: &crate::Subtree, input: &mut TtCursor) -> Result<Bindings,
_ => return Err(ExpandError::UnexpectedToken), _ => return Err(ExpandError::UnexpectedToken),
}, },
crate::TokenTree::Repeat(crate::Repeat { subtree, kind: _, separator }) => { crate::TokenTree::Repeat(crate::Repeat { subtree, kind: _, separator }) => {
// Dirty hack to make macro-expansion terminate.
// This should be replaced by a propper macro-by-example implementation
let mut limit = 128;
while let Ok(nested) = match_lhs(subtree, input) { while let Ok(nested) = match_lhs(subtree, input) {
limit -= 1;
if limit == 0 {
break;
}
res.push_nested(nested)?; res.push_nested(nested)?;
if let Some(separator) = *separator { if let Some(separator) = *separator {
if !input.is_eof() { if !input.is_eof() {
@ -196,7 +203,14 @@ fn expand_tt(
crate::TokenTree::Repeat(repeat) => { crate::TokenTree::Repeat(repeat) => {
let mut token_trees = Vec::new(); let mut token_trees = Vec::new();
nesting.push(0); nesting.push(0);
// Dirty hack to make macro-expansion terminate.
// This should be replaced by a propper macro-by-example implementation
let mut limit = 128;
while let Ok(t) = expand_subtree(&repeat.subtree, bindings, nesting) { while let Ok(t) = expand_subtree(&repeat.subtree, bindings, nesting) {
limit -= 1;
if limit == 0 {
break;
}
let idx = nesting.pop().unwrap(); let idx = nesting.pop().unwrap();
nesting.push(idx + 1); nesting.push(idx + 1);
token_trees.push(t.into()) token_trees.push(t.into())