From 6649da3f5d69c619e9e549b1927d4971130d44d4 Mon Sep 17 00:00:00 2001
From: JT <547158+jntrnr@users.noreply.github.com>
Date: Sun, 3 Apr 2022 10:41:36 +1200
Subject: [PATCH] Add support for single value row conditions (#5072)

---
 crates/nu-parser/src/parser.rs | 9 ++++++++-
 src/tests/test_parser.rs       | 8 ++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/crates/nu-parser/src/parser.rs b/crates/nu-parser/src/parser.rs
index 7b3b33558..859d46419 100644
--- a/crates/nu-parser/src/parser.rs
+++ b/crates/nu-parser/src/parser.rs
@@ -3993,7 +3993,7 @@ pub fn parse_math_expression(
     let mut last_prec = 1000000;
 
     let mut error = None;
-    let (lhs, err) = parse_value(
+    let (mut lhs, err) = parse_value(
         working_set,
         spans[0],
         &SyntaxShape::Any,
@@ -4002,6 +4002,13 @@ pub fn parse_math_expression(
     error = error.or(err);
     idx += 1;
 
+    if idx >= spans.len() {
+        // We already found the one part of our expression, so let's expand
+        if let Some(row_var_id) = lhs_row_var_id {
+            expand_to_cell_path(working_set, &mut lhs, row_var_id, expand_aliases_denylist);
+        }
+    }
+
     expr_stack.push(lhs);
 
     while idx < spans.len() {
diff --git a/src/tests/test_parser.rs b/src/tests/test_parser.rs
index c457236f3..e98c61e1f 100644
--- a/src/tests/test_parser.rs
+++ b/src/tests/test_parser.rs
@@ -367,3 +367,11 @@ fn proper_rest_types() -> TestResult {
         "not verbose!",
     )
 }
+
+#[test]
+fn single_value_row_condition() -> TestResult {
+    run_test(
+        r#"[[a, b]; [true, false], [true, true]] | where a | length"#,
+        "2",
+    )
+}