Add test for rest pattern

testing/tests/rest_pattern.rs

@@ -1,78 +1,26 @@
 use rinja::Template;
 
-#[test]
-fn a() {
-    #[derive(Template)]
-    #[template(source = "{% if let (a, ..) = abc  %}-{{a}}-{% endif %}", ext = "txt")]
-    struct Tmpl {
-        abc: (u32, u32, u32),
-    }
-
-    assert_eq!(Tmpl { abc: (1, 2, 3) }.to_string(), "-1-");
-}
-
-#[test]
-fn ab() {
-    #[derive(Template)]
-    #[template(
-        source = "{% if let (a, b, ..) = abc  %}-{{a}}{{b}}-{% endif %}",
-        ext = "txt"
-    )]
-    struct Tmpl {
-        abc: (u32, u32, u32),
-    }
-
-    assert_eq!(Tmpl { abc: (1, 2, 3) }.to_string(), "-12-");
-}
+#[derive(Template)]
+#[template(
+    source = r#"
+{%- if let [1, 2, who @ .., 4] = [1, 2, 3, 4] -%}
+111> {{"{:?}"|format(who)}}
+{%- endif -%}
+{%- if let [who @ .., 4] = [1, 2, 3, 4] -%}
+222> {{"{:?}"|format(who)}}
+{%- endif -%}
+{%- if let [1, who @ ..] = [1, 2, 3, 4] -%}
+333> {{"{:?}"|format(who)}}
+{%- endif -%}
+"#,
+    ext = "txt"
+)]
+struct Rest;
 
 #[test]
-fn abc() {
-    #[derive(Template)]
-    #[template(
-        source = "{% if let (a, b, c, ..) = abc  %}-{{a}}{{b}}{{c}}-{% endif %}",
-        ext = "txt"
-    )]
-    struct Tmpl1 {
-        abc: (u32, u32, u32),
-    }
-
-    assert_eq!(Tmpl1 { abc: (1, 2, 3) }.to_string(), "-123-");
-
-    assert_eq!(Tmpl2 { abc: (1, 2, 3) }.to_string(), "-123-");
-
-    #[derive(Template)]
-    #[template(
-        source = "{% if let (a, b, c, ..) = abc  %}-{{a}}{{b}}{{c}}-{% endif %}",
-        ext = "txt"
-    )]
-    struct Tmpl2 {
-        abc: (u32, u32, u32),
-    }
-
-    assert_eq!(Tmpl2 { abc: (1, 2, 3) }.to_string(), "-123-");
-}
-
-#[test]
-fn bc() {
-    #[derive(Template)]
-    #[template(
-        source = "{% if let (.., b, c) = abc  %}-{{b}}{{c}}-{% endif %}",
-        ext = "txt"
-    )]
-    struct Tmpl {
-        abc: (u32, u32, u32),
-    }
-
-    assert_eq!(Tmpl { abc: (1, 2, 3) }.to_string(), "-23-");
-}
-
-#[test]
-fn c() {
-    #[derive(Template)]
-    #[template(source = "{% if let (.., c) = abc  %}-{{c}}-{% endif %}", ext = "txt")]
-    struct Tmpl {
-        abc: (u32, u32, u32),
-    }
-
-    assert_eq!(Tmpl { abc: (1, 2, 3) }.to_string(), "-3-");
+fn test_rest() {
+    assert_eq!(
+        Rest.render().unwrap(),
+        "111> [3]222> [1, 2, 3]333> [2, 3, 4]"
+    );
 }

testing/tests/ui/rest_pattern.rs

@@ -0,0 +1,60 @@
+use rinja::Template;
+
+// Checking that we can't use `..` more than once.
+#[derive(Template)]
+#[template(
+    source = r#"
+{%- if let [1, 2, who @ .., 4, ..] = [1, 2, 3, 4] -%}
+{%- endif -%}
+"#,
+    ext = "txt"
+)]
+struct Err1;
+
+#[derive(Template)]
+#[template(
+    source = r#"
+{%- if let (.., 1, 2, .., 4) = (1, 2, 3, 4) -%}
+{%- endif -%}
+"#,
+    ext = "txt"
+)]
+struct Err2;
+
+// This code doesn't make sense but the goal is to ensure that you can't
+// use `..` in a struct more than once.
+#[derive(Template)]
+#[template(
+    source = r#"
+{%- if let Cake { .., a, .. } = [1, 2, 3, 4] -%}
+{%- endif -%}
+"#,
+    ext = "txt"
+)]
+struct Err3;
+
+// Now checking we can't use `@ ..` in tuples and structs.
+#[derive(Template)]
+#[template(
+    source = r#"
+{%- if let (1, 2, who @ .., 4) = (1, 2, 3, 4) -%}
+{%- endif -%}
+"#,
+    ext = "txt"
+)]
+struct Err4;
+
+// This code doesn't make sense but the goal is to ensure that you can't
+// use `@ ..` in a struct so here we go.
+#[derive(Template)]
+#[template(
+    source = r#"
+{%- if let Cake { a, who @ .. } = [1, 2, 3, 4] -%}
+{%- endif -%}
+"#,
+    ext = "txt"
+)]
+struct Err5;
+
+fn main() {
+}

testing/tests/ui/rest_pattern.stderr

@@ -0,0 +1,60 @@
+error: `..` can only be used once per array pattern
+ --> <source attribute>:2:31
+       "..] = [1, 2, 3, 4] -%}\n{%- endif -%}\n"
+ --> tests/ui/rest_pattern.rs:6:14
+  |
+6 |       source = r#"
+  |  ______________^
+7 | | {%- if let [1, 2, who @ .., 4, ..] = [1, 2, 3, 4] -%}
+8 | | {%- endif -%}
+9 | | "#,
+  | |__^
+
+error: `..` can only be used once per tuple pattern
+ --> <source attribute>:2:22
+       ".., 4) = (1, 2, 3, 4) -%}\n{%- endif -%}\n"
+  --> tests/ui/rest_pattern.rs:16:14
+   |
+16 |       source = r#"
+   |  ______________^
+17 | | {%- if let (.., 1, 2, .., 4) = (1, 2, 3, 4) -%}
+18 | | {%- endif -%}
+19 | | "#,
+   | |__^
+
+error: unexpected `,` character after `..`
+       note that in a named struct, `..` must come last to ignore other members
+         --> <source attribute>:2:20
+       ", a, .. } = [1, 2, 3, 4] -%}\n{%- endif -%}\n"
+  --> tests/ui/rest_pattern.rs:28:14
+   |
+28 |       source = r#"
+   |  ______________^
+29 | | {%- if let Cake { .., a, .. } = [1, 2, 3, 4] -%}
+30 | | {%- endif -%}
+31 | | "#,
+   | |__^
+
+error: `@ ..` cannot be used in tuple
+ --> <source attribute>:2:18
+       "who @ .., 4) = (1, 2, 3, 4) -%}\n{%- endif -%}\n"
+  --> tests/ui/rest_pattern.rs:39:14
+   |
+39 |       source = r#"
+   |  ______________^
+40 | | {%- if let (1, 2, who @ .., 4) = (1, 2, 3, 4) -%}
+41 | | {%- endif -%}
+42 | | "#,
+   | |__^
+
+error: `@ ..` cannot be used in struct
+ --> <source attribute>:2:21
+       "who @ .. } = [1, 2, 3, 4] -%}\n{%- endif -%}\n"
+  --> tests/ui/rest_pattern.rs:51:14
+   |
+51 |       source = r#"
+   |  ______________^
+52 | | {%- if let Cake { a, who @ .. } = [1, 2, 3, 4] -%}
+53 | | {%- endif -%}
+54 | | "#,
+   | |__^