Improve error output

askama_derive/src/generator/node.rs

@@ -1127,10 +1127,14 @@ impl<'a> Generator<'a, '_> {
                 ctx: &Context<'a>,
                 expected: usize,
                 found: usize,
+                name: &str,
             ) -> Result<(), CompileError> {
                 if expected != found {
                     Err(ctx.generate_error(
-                        format!("expected `{}` argument, found `{}`", expected, found),
+                        format!(
+                            "expected {expected} argument{} in `{name}`, found {found}",
+                            if expected != 1 { "s" } else { "" }
+                        ),
                         s.span(),
                     ))
                 } else {
@@ -1138,11 +1142,11 @@ impl<'a> Generator<'a, '_> {
                 }
             }
             if ***path == Expr::Var("super") {
-                check_num_args(s, ctx, 0, expr_args.len())?;
+                check_num_args(s, ctx, 0, expr_args.len(), "super")?;
                 return self.write_block(ctx, buf, None, ws, s.span());
             } else if ***path == Expr::Var("caller") {
                 let def = self.active_caller.ok_or_else(|| {
-                    ctx.generate_error(format_args!("block is not defined for caller"), s.span())
+                    ctx.generate_error(format_args!("block is not defined for `caller`"), s.span())
                 })?;
                 self.active_caller = None;
                 self.handle_ws(ws);
@@ -1151,7 +1155,7 @@ impl<'a> Generator<'a, '_> {
                     buf.write('{');
                     this.prepare_ws(def.ws1);
                     let mut value = Buffer::new();
-                    check_num_args(s, ctx, def.caller_args.len(), expr_args.len())?;
+                    check_num_args(s, ctx, def.caller_args.len(), expr_args.len(), "caller")?;
                     for (index, arg) in def.caller_args.iter().enumerate() {
                         match expr_args.get(index) {
                             Some(expr) => {

testing/tests/ui/caller_arguments.stderr

@@ -1,4 +1,4 @@
-error: expected `3` argument, found `2`
+error: expected 3 arguments in `caller`, found 2
  --> InvalidNumberArguments.txt:3:18
        "(\"a\", \"b\") -}}\n    {%- endmacro -%}\n    {%- call(a,b,c) test() -%}\n        {{- a"...
   --> tests/ui/caller_arguments.rs:5:14
@@ -13,85 +13,85 @@ error: expected `3` argument, found `2`
 12 | |     "#,
    | |______^
 
-error: expected `1` argument, found `2`
+error: expected 1 argument in `caller`, found 2
  --> InvalidNumberArguments1.txt:3:18
        "(\"a\", \"b\") -}}\n    {%- endmacro -%}\n    {%- call(a) test() -%}\n        {{- a -}}"...
-  --> tests/ui/caller_arguments.rs:21:14
+  --> tests/ui/caller_arguments.rs:20:14
    |
-21 |       source = r#"
+20 |       source = r#"
    |  ______________^
-22 | |     {% macro test() %}
-23 | |         {{- caller("a", "b") -}}
-24 | |     {%- endmacro -%}
+21 | |     {% macro test() %}
+22 | |         {{- caller("a", "b") -}}
+23 | |     {%- endmacro -%}
 ...  |
-27 | |     {%- endcall -%}
-28 | |     "#,
+26 | |     {%- endcall -%}
+27 | |     "#,
    | |______^
 
 error: expected `)` to close call argument list
  --> <source attribute>:5:15
        "test() -%}\n        {{- a -}}\n    {%- endcall -%}\n    "
-  --> tests/ui/caller_arguments.rs:36:14
+  --> tests/ui/caller_arguments.rs:35:14
    |
-36 |       source = r#"
+35 |       source = r#"
    |  ______________^
-37 | |     {% macro test() %}
-38 | |         {{- caller("a") -}}
-39 | |     {%- endmacro -%}
+36 | |     {% macro test() %}
+37 | |         {{- caller("a") -}}
+38 | |     {%- endmacro -%}
 ...  |
-42 | |     {%- endcall -%}
-43 | |     "#,
+41 | |     {%- endcall -%}
+42 | |     "#,
    | |______^
 
-error: block is not defined for caller
+error: block is not defined for `caller`
  --> CallerInCaller.txt:6:18
        "(a) -}}\n    {%- endcall -%}\n    "
-  --> tests/ui/caller_arguments.rs:51:14
+  --> tests/ui/caller_arguments.rs:50:14
    |
-51 |       source = r#"
+50 |       source = r#"
    |  ______________^
-52 | |     {% macro test() %}
-53 | |         {{- caller("a") -}}
-54 | |     {%- endmacro -%}
+51 | |     {% macro test() %}
+52 | |         {{- caller("a") -}}
+53 | |     {%- endmacro -%}
 ...  |
-57 | |     {%- endcall -%}
-58 | |     "#,
+56 | |     {%- endcall -%}
+57 | |     "#,
    | |______^
 
-error: block is not defined for caller
+error: block is not defined for `caller`
  --> CallerInCaller1.txt:10:21
        "(\"b\") }}\n        {% endcall %}\n        {{- a -}}\n    {%- endcall -%}\n    "
-  --> tests/ui/caller_arguments.rs:66:14
+  --> tests/ui/caller_arguments.rs:65:14
    |
-66 |       source = r#"
+65 |       source = r#"
    |  ______________^
-67 | |     {% macro test2() %}
-68 | |         {{ caller("bb") }}
-69 | |     {% endmacro %}
+66 | |     {% macro test2() %}
+67 | |         {{ caller("bb") }}
+68 | |     {% endmacro %}
 ...  |
-78 | |     {%- endcall -%}
-79 | |     "#,
+77 | |     {%- endcall -%}
+78 | |     "#,
    | |______^
 
-error: block is not defined for caller
+error: block is not defined for `caller`
  --> JustCaller.txt:1:8
        "()}}"
-  --> tests/ui/caller_arguments.rs:87:14
+  --> tests/ui/caller_arguments.rs:86:14
    |
-87 |     source = r#"{{caller()}}"#,
+86 |     source = r#"{{caller()}}"#,
    |              ^^^^^^^^^^^^^^^^^
 
 error: failed to parse template source
  --> <source attribute>:3:27
        "= \"b\") }}\n    {%- endmacro -%}\n    {%- call(two, one) test() -%}\n        {{- two"...
-   --> tests/ui/caller_arguments.rs:95:14
+   --> tests/ui/caller_arguments.rs:94:14
     |
-95  |       source = r#"
+94  |       source = r#"
     |  ______________^
-96  | |     {% macro test() %}
-97  | |         {{ caller("a", one = "b") }}
-98  | |     {%- endmacro -%}
+95  | |     {% macro test() %}
+96  | |         {{ caller("a", one = "b") }}
+97  | |     {%- endmacro -%}
 ...   |
-101 | |     {%- endcall -%}
-102 | |     "#,
+100 | |     {%- endcall -%}
+101 | |     "#,
     | |______^