Reject removed share parameter effect

Author: olwang

src/analyzer.rs

@@ -138,7 +138,33 @@ impl Analyzer<'_> {
                         ),
                     );
                 }
-                if param.effect.is_none() && !param.ty.name.is_empty() && !is_copy_type(&param.ty) {
+                if param.effect.is_none() && param.ty.name == "share" {
+                    self.diagnostics.push(
+                        Diagnostic::error(
+                            code::REMOVED_SHARE_EFFECT,
+                            format!(
+                                "parameter `{}` in `{}` uses removed `share` data effect.",
+                                param.name, function.name
+                            ),
+                            param.ty.span.clone(),
+                            "removed share data effect",
+                        )
+                        .with_cause("RSScript v0.4.1 has exactly three data effects: `read`, `mut`, and `take`.")
+                        .with_fix(
+                            "replace_share_effect",
+                            format!(
+                                "Use `{}: read T` and add `effects(retains({}))` if the function retains it.",
+                                param.name, param.name
+                            ),
+                            "manual",
+                        ),
+                    );
+                }
+                if param.effect.is_none()
+                    && !param.ty.name.is_empty()
+                    && param.ty.name != "share"
+                    && !is_copy_type(&param.ty)
+                {
                     self.diagnostics.push(
                         Diagnostic::error(
                             code::MISSING_PARAMETER_EFFECT,

src/diagnostic.rs

@@ -11,6 +11,7 @@ pub mod code {
     pub const MISSING_PARAMETER_EFFECT: &str = "RS0008";
     pub const INVALID_PURE_EFFECT: &str = "RS0009";
     pub const REMOVED_PROFILE_DECLARATION: &str = "RS0010";
+    pub const REMOVED_SHARE_EFFECT: &str = "RS0011";
     pub const FILE_MODE_VIOLATION: &str = "RS0101";
     pub const UNNAMED_ARGUMENT: &str = "RS0201";
     pub const MISSING_DATA_EFFECT: &str = "RS0202";
@@ -249,6 +250,11 @@ static DIAGNOSTIC_EXPLANATIONS: &[DiagnosticExplanation] = &[
         title: "removed profile declaration",
         explanation: "RSScript v0.4.1 removed `profile:` declarations. The only top-level semantic file declaration is `mode:`.",
     },
+    DiagnosticExplanation {
+        code: code::REMOVED_SHARE_EFFECT,
+        title: "removed share data effect",
+        explanation: "RSScript v0.4.1 removed `share` as a data effect. Retention must be declared with `effects(retains(param))`.",
+    },
     DiagnosticExplanation {
         code: code::FILE_MODE_VIOLATION,
         title: "file mode violation",

tests/fixtures/fail/removed-share-parameter-effect.rss

@@ -0,0 +1,10 @@
+// expect: RS0011
+mode: managed
+
+struct Image {
+    pixels: Buffer
+}
+
+fn cache_put(value: share Image) -> Unit {
+    return Unit
+}