2 files changed, 15 insertions, 9 deletions

diff --git a/crates/syntax/Cargo.toml b/crates/syntax/Cargo.toml
index 9f01acc26..a8c1a8075 100644
--- a/crates/syntax/Cargo.toml
+++ b/crates/syntax/Cargo.toml
@@ -13,10 +13,10 @@ doctest = false
 [dependencies]
 cov-mark = { version = "1.1", features = ["thread-local"] }
 itertools = "0.10.0"
-rowan = "0.13.0-pre.3"
-rustc_lexer = { version = "710.0.0", package = "rustc-ap-rustc_lexer" }
+rowan = "=0.13.0-pre.3"
+rustc_lexer = { version = "714.0.0", package = "rustc-ap-rustc_lexer" }
 rustc-hash = "1.1.0"
-arrayvec = "0.6"
+arrayvec = "0.7"
 once_cell = "1.3.1"
 indexmap = "1.4.0"
 smol_str = { version = "0.1.15", features = ["serde"] }
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index c6a7b99b7..94d4f2cf0 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -29,9 +29,13 @@ pub fn ty(text: &str) -> ast::Type {
 pub fn ty_unit() -> ast::Type {
     ty("()")
 }
-// FIXME: handle types of length == 1
 pub fn ty_tuple(types: impl IntoIterator<Item = ast::Type>) -> ast::Type {
-    let contents = types.into_iter().join(", ");
+    let mut count: usize = 0;
+    let mut contents = types.into_iter().inspect(|_| count += 1).join(", ");
+    if count == 1 {
+        contents.push(',');
+    }
+
     ty(&format!("({})", contents))
 }
 // FIXME: handle path to type
@@ -292,11 +296,13 @@ pub fn wildcard_pat() -> ast::WildcardPat {
 
 /// Creates a tuple of patterns from an iterator of patterns.
 ///
-/// Invariant: `pats` must be length > 1
-///
-/// FIXME handle `pats` length == 1
+/// Invariant: `pats` must be length > 0
 pub fn tuple_pat(pats: impl IntoIterator<Item = ast::Pat>) -> ast::TuplePat {
-    let pats_str = pats.into_iter().map(|p| p.to_string()).join(", ");
+    let mut count: usize = 0;
+    let mut pats_str = pats.into_iter().inspect(|_| count += 1).join(", ");
+    if count == 1 {
+        pats_str.push(',');
+    }
     return from_text(&format!("({})", pats_str));
 
     fn from_text(text: &str) -> ast::TuplePat {