Remove implicit **kwargs injection

Using {**name} without declaring **name as a parameter would
silently inject it into the function signature. This is wrong —
the name could refer to a local variable, not an intended parameter.
Spread requires explicit declaration, same as Python.

Author: scriptogre

rust/src/generate/python.rs

@@ -1704,15 +1704,6 @@ impl Generator for PythonGenerator {
             }
         }
 
-        // Implicit **kwargs: if body uses a single {**name} and no **kwargs param
-        // is declared, auto-add **name to the signature
-        let implicit_kwargs_name = if star_star_kwargs.is_none() && metadata.spread_names.len() == 1
-        {
-            metadata.spread_names.iter().next().cloned()
-        } else {
-            None
-        };
-
         // Emit _content parameter first if default slot is used
         let mut param_count = 0;
         if has_default_slot {
@@ -1786,12 +1777,6 @@ impl Generator for PythonGenerator {
                 output.push(": ");
                 output.push(type_hint);
             }
-        } else if let Some(name) = &implicit_kwargs_name {
-            if param_count > 0 || !regular_params.is_empty() || has_named_slots {
-                output.push(", ");
-            }
-            output.push("**");
-            output.push(name);
         }
 
         output.push("):");

rust/src/transform/metadata.rs

@@ -7,8 +7,6 @@ pub struct TransformMetadata {
     pub helpers_used: HashSet<String>,
     pub is_async: bool,
     pub slots_used: HashSet<String>,
-    /// All {**name} spread variable names found in the body
-    pub spread_names: HashSet<String>,
 }
 
 impl TransformMetadata {

rust/src/transform/mod.rs

@@ -2,13 +2,11 @@ mod async_detect;
 mod helper_detect;
 mod metadata;
 mod slot_detect;
-mod spread_detect;
 
 pub use async_detect::AsyncDetectionPlugin;
 pub use helper_detect::HelperDetectionPlugin;
 pub use metadata::TransformMetadata;
 pub use slot_detect::SlotDetectionPlugin;
-pub use spread_detect::SpreadDetectionPlugin;
 
 use crate::ast::{Ast, Node};
 
@@ -141,5 +139,4 @@ pub fn standard_plugins() -> Transformer {
         .add(HelperDetectionPlugin)
         .add(AsyncDetectionPlugin)
         .add(SlotDetectionPlugin)
-        .add(SpreadDetectionPlugin)
 }

rust/src/transform/spread_detect.rs

@@ -1412,47 +1412,3 @@ fn test_shorthand_and_spread_together_on_component() {
         result.code
     );
 }
-
-// ========================================================================
-// Implicit spread edge cases
-// ========================================================================
-
-#[test]
-fn test_implicit_spread_adds_kwargs_to_signature() {
-    // {**attrs} used without declaring **attrs — compiler auto-adds it
-    let source = "label: str\n---\n<button {**attrs}>{label}</button>";
-    let result = compile_with_ranges(source, "Test");
-
-    let sig = result.code.lines().find(|l| l.contains("def ")).unwrap();
-    assert!(
-        sig.contains("**attrs"),
-        "Implicit spread should add **attrs to signature. Got: {}",
-        sig
-    );
-}
-
-#[test]
-fn test_multiple_spread_names_require_explicit_declaration() {
-    // Two elements use different spread names — implicit can't handle this
-    // (Python only allows one **kwargs), so both must be declared explicitly
-    let source = "container_attrs: dict\nbutton_attrs: dict\n---\n<div {**container_attrs}>\n    <button {**button_attrs}>Click</button>\n</div>";
-    let result = compile_with_ranges(source, "Test");
-
-    assert!(
-        result.code.contains("spread_attrs(container_attrs)"),
-        "First spread should compile. Got:\n{}",
-        result.code
-    );
-    assert!(
-        result.code.contains("spread_attrs(button_attrs)"),
-        "Second spread should compile. Got:\n{}",
-        result.code
-    );
-    // Both are regular dict params, not **kwargs
-    let sig_line = result.code.lines().find(|l| l.contains("def ")).unwrap();
-    assert!(
-        sig_line.contains("container_attrs: dict") && sig_line.contains("button_attrs: dict"),
-        "Both should be regular dict params. Sig: {}",
-        sig_line
-    );
-}