error on '(,)'-tuples

Currently creats a lot of syntax errors. See #100.

2 files changed, 15 insertions, 0 deletions

diff --git a/progs/tests/tuples_fail_invalid_singleton.sy b/progs/tests/tuples_fail_invalid_singleton.sy
new file mode 100644
index 0000000..c70fc21
--- /dev/null
+++ b/progs/tests/tuples_fail_invalid_singleton.sy
@@ -0,0 +1,7 @@
+start :: fn {
+    a := (,)
+    a
+}
+
+//TODO(gu) See #100
+// errors: [ErrorKind::SyntaxError(_, _), ErrorKind::SyntaxError(_, _), ErrorKind::SyntaxError(_, _), ErrorKind::SyntaxError(_, _)]
diff --git a/src/compiler.rs b/src/compiler.rs
index 46fe38c..c4f687f 100644
--- a/src/compiler.rs
+++ b/src/compiler.rs
@@ -691,6 +691,14 @@ impl Compiler {
                 Token::Newline => {
                     self.eat();
                 }
+                Token::Comma => {
+                    //TODO(gu): This creates a lot of syntax errors since the compiler panic is
+                    // ignored and the statement is tried as a grouping instead, even though we
+                    // _know_ that this can't be parsed as a grouping either.
+                    // Tracked in #100.
+                    error!(self, "Tuples must begin with an element or ')'.");
+                    return;
+                }
                 _ => {
                     self.expression(block);
                     num_args += 1;