bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir-def/src/body/lower.rs')
-rw-r--r--crates/hir-def/src/body/lower.rs40
1 files changed, 34 insertions, 6 deletions
diff --git a/crates/hir-def/src/body/lower.rs b/crates/hir-def/src/body/lower.rs
index acc9943481..ebe05afca6 100644
--- a/crates/hir-def/src/body/lower.rs
+++ b/crates/hir-def/src/body/lower.rs
@@ -542,9 +542,18 @@ impl ExprCollector<'_> {
self.alloc_expr(Expr::BinaryOp { lhs, rhs, op }, syntax_ptr)
}
ast::Expr::TupleExpr(e) => {
- let exprs = e.fields().map(|expr| self.collect_expr(expr)).collect();
+ let mut exprs: Vec<_> = e.fields().map(|expr| self.collect_expr(expr)).collect();
+ // if there is a leading comma, the user is most likely to type out a leading expression
+ // so we insert a missing expression at the beginning for IDE features
+ if comma_follows_token(e.l_paren_token()) {
+ exprs.insert(0, self.missing_expr());
+ }
+
self.alloc_expr(
- Expr::Tuple { exprs, is_assignee_expr: self.is_lowering_assignee_expr },
+ Expr::Tuple {
+ exprs: exprs.into_boxed_slice(),
+ is_assignee_expr: self.is_lowering_assignee_expr,
+ },
syntax_ptr,
)
}
@@ -1180,7 +1189,11 @@ impl ExprCollector<'_> {
ast::Pat::TupleStructPat(p) => {
let path =
p.path().and_then(|path| self.expander.parse_path(self.db, path)).map(Box::new);
- let (args, ellipsis) = self.collect_tuple_pat(p.fields(), binding_list);
+ let (args, ellipsis) = self.collect_tuple_pat(
+ p.fields(),
+ comma_follows_token(p.l_paren_token()),
+ binding_list,
+ );
Pat::TupleStruct { path, args, ellipsis }
}
ast::Pat::RefPat(p) => {
@@ -1199,7 +1212,11 @@ impl ExprCollector<'_> {
}
ast::Pat::ParenPat(p) => return self.collect_pat_opt(p.pat(), binding_list),
ast::Pat::TuplePat(p) => {
- let (args, ellipsis) = self.collect_tuple_pat(p.fields(), binding_list);
+ let (args, ellipsis) = self.collect_tuple_pat(
+ p.fields(),
+ comma_follows_token(p.l_paren_token()),
+ binding_list,
+ );
Pat::Tuple { args, ellipsis }
}
ast::Pat::WildcardPat(_) => Pat::Wild,
@@ -1323,18 +1340,24 @@ impl ExprCollector<'_> {
fn collect_tuple_pat(
&mut self,
args: AstChildren<ast::Pat>,
+ has_leading_comma: bool,
binding_list: &mut BindingList,
) -> (Box<[PatId]>, Option<usize>) {
// Find the location of the `..`, if there is one. Note that we do not
// consider the possibility of there being multiple `..` here.
let ellipsis = args.clone().position(|p| matches!(p, ast::Pat::RestPat(_)));
// We want to skip the `..` pattern here, since we account for it above.
- let args = args
+ let mut args: Vec<_> = args
.filter(|p| !matches!(p, ast::Pat::RestPat(_)))
.map(|p| self.collect_pat(p, binding_list))
.collect();
+ // if there is a leading comma, the user is most likely to type out a leading pattern
+ // so we insert a missing pattern at the beginning for IDE features
+ if has_leading_comma {
+ args.insert(0, self.missing_pat());
+ }
- (args, ellipsis)
+ (args.into_boxed_slice(), ellipsis)
}
// endregion: patterns
@@ -1493,3 +1516,8 @@ impl ExprCollector<'_> {
self.body.labels.alloc(label)
}
}
+
+fn comma_follows_token(t: Option<syntax::SyntaxToken>) -> bool {
+ (|| syntax::algo::skip_trivia_token(t?.next_token()?, syntax::Direction::Next))()
+ .map_or(false, |it| it.kind() == syntax::T![,])
+}