Delegation: fix ICE with invalid MethodCall generation

Author: Bryanskiy

compiler/rustc_ast_lowering/src/delegation.rs

@@ -149,6 +149,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
+    fn is_assoc_fn(&self, sig_id: DefId) -> bool {
+        match sig_id.as_local() {
+            Some(local_sig_id) => match self.resolver.delegation_fn_sigs.get(&local_sig_id) {
+                Some(sig) => sig.is_assoc_item,
+                None => false,
+            },
+            None => self.tcx.def_kind(sig_id) == DefKind::AssocFn,
+        }
+    }
+
     fn lower_delegation_decl(
         &mut self,
         sig_id: DefId,
@@ -324,7 +334,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
         let call = if self
             .get_resolution_id(delegation.id, span)
-            .and_then(|def_id| Ok(self.has_self(def_id, span)))
+            .and_then(|def_id| Ok(self.has_self(def_id, span) && self.is_assoc_fn(def_id)))
             .unwrap_or_default()
             && delegation.qself.is_none()
             && !has_generic_args

compiler/rustc_middle/src/ty/mod.rs

@@ -224,6 +224,7 @@ pub struct DelegationFnSig {
     pub has_self: bool,
     pub c_variadic: bool,
     pub target_feature: bool,
+    pub is_assoc_item: bool,
 }
 
 #[derive(Clone, Copy, Debug)]

compiler/rustc_resolve/src/late.rs

@@ -5056,13 +5056,20 @@ struct ItemInfoCollector<'a, 'ra, 'tcx> {
 }
 
 impl ItemInfoCollector<'_, '_, '_> {
-    fn collect_fn_info(&mut self, sig: &FnSig, id: NodeId, attrs: &[Attribute]) {
+    fn collect_fn_info(
+        &mut self,
+        sig: &FnSig,
+        id: NodeId,
+        attrs: &[Attribute],
+        is_assoc_item: bool,
+    ) {
         let sig = DelegationFnSig {
             header: sig.header,
             param_count: sig.decl.inputs.len(),
             has_self: sig.decl.has_self(),
             c_variadic: sig.decl.c_variadic(),
             target_feature: attrs.iter().any(|attr| attr.has_name(sym::target_feature)),
+            is_assoc_item,
         };
         self.r.delegation_fn_sigs.insert(self.r.local_def_id(id), sig);
     }
@@ -5081,7 +5088,7 @@ impl<'ast> Visitor<'ast> for ItemInfoCollector<'_, '_, '_> {
             | ItemKind::Trait(box Trait { generics, .. })
             | ItemKind::TraitAlias(generics, _) => {
                 if let ItemKind::Fn(box Fn { sig, .. }) = &item.kind {
-                    self.collect_fn_info(sig, item.id, &item.attrs);
+                    self.collect_fn_info(sig, item.id, &item.attrs, false);
                 }
 
                 let def_id = self.r.local_def_id(item.id);
@@ -5114,7 +5121,7 @@ impl<'ast> Visitor<'ast> for ItemInfoCollector<'_, '_, '_> {
 
     fn visit_assoc_item(&mut self, item: &'ast AssocItem, ctxt: AssocCtxt) {
         if let AssocItemKind::Fn(box Fn { sig, .. }) = &item.kind {
-            self.collect_fn_info(sig, item.id, &item.attrs);
+            self.collect_fn_info(sig, item.id, &item.attrs, true);
         }
         visit::walk_assoc_item(self, item, ctxt);
     }

tests/crashes/127916.rs

@@ -0,0 +1,9 @@
+#![feature(fn_delegation)]
+#![allow(incomplete_features)]
+
+fn a(&self) {}
+//~^ ERROR `self` parameter is only allowed in associated functions
+
+reuse a as b;
+
+fn main() {}

tests/crashes/128119.rs

@@ -0,0 +1,10 @@
+error: `self` parameter is only allowed in associated functions
+  --> $DIR/ice-isssue-128190.rs:4:6
+   |
+LL | fn a(&self) {}
+   |      ^^^^^ not semantically valid as function parameter
+   |
+   = note: associated functions are those in `impl` or `trait` definitions
+
+error: aborting due to 1 previous error
+