Repository: Instagram/LibCST (language: python)

Issue:
Incorrectly triggered "CSTValidationError: Cannot have unbalanced parens"
Hey, 

This error can be triggered as follows:
```python
cst.parse_module("a = (())\n")
```
which causes my application to crash. This was probably introduced in a recent update since it worked fine on "<=0.4.2" but not on ">=0.4.4".

Also I'm parsing with `LIBCST_PARSER_TYPE=native`.


Discussion / hints:
Bisect says this regression was introduced in 380f045fe05bfdc6a0555f8e36a0c1c406ca1b77. I'll check it out ASAP

Fix patch:
diff --git a/native/libcst/src/nodes/expression.rs b/native/libcst/src/nodes/expression.rs
index 15abe99b2..ab6b90030 100644
--- a/native/libcst/src/nodes/expression.rs
+++ b/native/libcst/src/nodes/expression.rs
@@ -1007,12 +1007,7 @@ impl<'r, 'a> Inflate<'a> for DeflatedTuple<'r, 'a> {
             .enumerate()
             .map(|(idx, el)| el.inflate_element(config, idx + 1 == len))
             .collect::<Result<Vec<_>>>()?;
-        let rpar = if !elements.is_empty() {
-            // rpar only has whitespace if elements is non empty
-            self.rpar.inflate(config)?
-        } else {
-            vec![Default::default()]
-        };
+        let rpar = self.rpar.inflate(config)?;
         Ok(Self::Inflated {
             elements,
             lpar,


Test patch:
diff --git a/native/libcst/tests/fixtures/tuple_shenanigans.py b/native/libcst/tests/fixtures/tuple_shenanigans.py
index f31c64523..136d79d25 100644
--- a/native/libcst/tests/fixtures/tuple_shenanigans.py
+++ b/native/libcst/tests/fixtures/tuple_shenanigans.py
@@ -4,6 +4,8 @@
 # alright here we go.
 
 ()
+(())
+(((())), ())
 ( # evil >:)
   # evil >:(
 ) # ...