Add regression test for .. pattern in structs

testing/tests/let_destructoring.rs

@@ -119,3 +119,29 @@ fn test_let_destruct_with_path_and_with_keyword() {
     };
     assert_eq!(t.render().unwrap(), "hello");
 }
+
+#[derive(Template)]
+#[template(
+    source = "
+{%- if let RestPattern2 { a, b } = x -%}hello {{ a }}{%- endif -%}
+{%- if let RestPattern2 { a, b, } = x -%}hello {{ b }}{%- endif -%}
+{%- if let RestPattern2 { a, .. } = x -%}hello {{ a }}{%- endif -%}
+",
+    ext = "html"
+)]
+struct RestPattern {
+    x: RestPattern2,
+}
+
+struct RestPattern2 {
+    a: u32,
+    b: u32,
+}
+
+#[test]
+fn test_has_rest_pattern() {
+    let t = RestPattern {
+        x: RestPattern2 { a: 0, b: 1 },
+    };
+    assert_eq!(t.render().unwrap(), "hello 0hello 1hello 0");
+}

testing/tests/ui/let_destructuring_has_rest.rs

@@ -0,0 +1,40 @@
+use rinja::Template;
+
+struct X {
+    a: u32,
+    b: u32,
+}
+
+#[derive(Template)]
+#[template(source = "
+{%- if let X { a, .. } = x -%}hello {{ a }}{%- endif -%}
+", ext = "html")]
+struct T1 {
+    x: X,
+}
+
+#[derive(Template)]
+#[template(source = "
+{%- if let X { a, .., } = x -%}hello {{ a }}{%- endif -%}
+", ext = "html")]
+struct T2 {
+    x: X,
+}
+
+#[derive(Template)]
+#[template(source = "
+{%- if let X { a .. } = x -%}hello {{ a }}{%- endif -%}
+", ext = "html")]
+struct T3 {
+    x: X,
+}
+
+#[derive(Template)]
+#[template(source = "
+{%- if let X { .. } = x -%}hello {{ a }}{%- endif -%}
+", ext = "html")]
+struct T4 {
+    x: X,
+}
+
+fn main() {}

testing/tests/ui/let_destructuring_has_rest.stderr

@@ -0,0 +1,26 @@
+error: unexpected `,` character after `..`
+       failed to parse template source at row 2, column 20 near:
+       ", } = x -%}hello {{ a }}{%- endif -%}\n"
+  --> tests/ui/let_destructuring_has_rest.rs:16:10
+   |
+16 | #[derive(Template)]
+   |          ^^^^^^^^
+   |
+   = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: failed to parse template source at row 2, column 17 near:
+       ".. } = x -%}hello {{ a }}{%- endif -%}\n"
+  --> tests/ui/let_destructuring_has_rest.rs:24:10
+   |
+24 | #[derive(Template)]
+   |          ^^^^^^^^
+   |
+   = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0609]: no field `a` on type `&T4`
+  --> tests/ui/let_destructuring_has_rest.rs:32:10
+   |
+32 | #[derive(Template)]
+   |          ^^^^^^^^ unknown field
+   |
+   = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)