Add range precedence tests

dtolnay · May 11, 2024 · 46bc5aa · 46bc5aa
1 parent b15c623
commit 46bc5aa
Showing 1 changed file with 58 additions and 1 deletion.
diff --git a/tests/test_expr.rs b/tests/test_expr.rs
@@ -331,7 +331,7 @@ fn test_postfix_operator_after_cast() {
 }
 
 #[test]
-fn test_ranges() {
+fn test_range_kinds() {
     syn::parse_str::<Expr>("..").unwrap();
     syn::parse_str::<Expr>("..hi").unwrap();
     syn::parse_str::<Expr>("lo..").unwrap();
@@ -348,6 +348,63 @@ fn test_ranges() {
     syn::parse_str::<Expr>("lo...hi").unwrap_err();
 }
 
+#[test]
+fn test_range_precedence() {
+    snapshot!(".. .." as Expr, @r###"
+    Expr::Range {
+        limits: RangeLimits::HalfOpen,
+        end: Some(Expr::Range {
+            limits: RangeLimits::HalfOpen,
+        }),
+    }
+    "###);
+
+    snapshot!(".. .. ()" as Expr, @r###"
+    Expr::Range {
+        limits: RangeLimits::HalfOpen,
+        end: Some(Expr::Range {
+            limits: RangeLimits::HalfOpen,
+            end: Some(Expr::Tuple),
+        }),
+    }
+    "###);
+
+    snapshot!("() .. .." as Expr, @r###"
+    Expr::Range {
+        start: Some(Expr::Tuple),
+        limits: RangeLimits::HalfOpen,
+        end: Some(Expr::Range {
+            limits: RangeLimits::HalfOpen,
+        }),
+    }
+    "###);
+
+    // FIXME: should fail to parse. A range with a lower bound cannot be the
+    // upper bound of another range.
+    snapshot!(".. () .." as Expr, @r###"
+    Expr::Range {
+        limits: RangeLimits::HalfOpen,
+        end: Some(Expr::Range {
+            start: Some(Expr::Tuple),
+            limits: RangeLimits::HalfOpen,
+        }),
+    }
+    "###);
+
+    // FIXME: should fail to parse. A range with an upper bound cannot be the
+    // lower bound of another range.
+    snapshot!("() .. () .." as Expr, @r###"
+    Expr::Range {
+        start: Some(Expr::Range {
+            start: Some(Expr::Tuple),
+            limits: RangeLimits::HalfOpen,
+            end: Some(Expr::Tuple),
+        }),
+        limits: RangeLimits::HalfOpen,
+    }
+    "###);
+}
+
 #[test]
 fn test_ambiguous_label() {
     for stmt in [