Rollup merge of #145065 - petrochenkov:riblock, r=davidtwco

resolve: Introduce `RibKind::Block`
to avoid confusing module items, blocks with items, and blocks without items.
Addresses #143141 (comment) and #143141 (comment).
A couple of related cleanups are also added on top.

Author: Zalathar

compiler/rustc_resolve/src/ident.rs

@@ -318,7 +318,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 let normalized_ident = Ident{span: normalized_span, ..ident };
 
 // Walk backwards up the ribs in scope.
-letmut module = self.graph_root;
 for(i, rib)in ribs.iter().enumerate().rev(){
 debug!("walk rib\n{:?}", rib.bindings);
 // Use the rib kind to determine whether we are resolving parameters
@@ -334,51 +333,47 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 *original_rib_ident_def,
  ribs,
 )));
+}elseifletRibKind::Block(Some(module)) = rib.kind
+ && letOk(binding) = self.cm().resolve_ident_in_module_unadjusted(
+ModuleOrUniformRoot::Module(module),
+ ident,
+ ns,
+ parent_scope,
+Shadowing::Unrestricted,
+ finalize.map(|finalize| Finalize{used:Used::Scope, ..finalize }),
+ ignore_binding,
+None,
+)
+{
+// The ident resolves to an item in a block.
+returnSome(LexicalScopeBinding::Item(binding));
+}elseifletRibKind::Module(module) = rib.kind{
+// Encountered a module item, abandon ribs and look into that module and preludes.
+returnself
+.cm()
+.early_resolve_ident_in_lexical_scope(
+ orig_ident,
+ScopeSet::Late(ns, module, finalize.map(|finalize| finalize.node_id)),
+ parent_scope,
+ finalize,
+ finalize.is_some(),
+ ignore_binding,
+None,
+)
+.ok()
+.map(LexicalScopeBinding::Item);
 }
 
- module = match rib.kind{
-RibKind::Module(module) => module,
-RibKind::MacroDefinition(def)if def == self.macro_def(ident.span.ctxt()) => {
-// If an invocation of this macro created `ident`, give up on `ident`
-// and switch to `ident`'s source from the macro definition.
- ident.span.remove_mark();
-continue;
-}
- _ => continue,
-};
-
-match module.kind{
-ModuleKind::Block => {}// We can see through blocks
- _ => break,
-}
-
-let item = self.cm().resolve_ident_in_module_unadjusted(
-ModuleOrUniformRoot::Module(module),
- ident,
- ns,
- parent_scope,
-Shadowing::Unrestricted,
- finalize.map(|finalize| Finalize{used:Used::Scope, ..finalize }),
- ignore_binding,
-None,
-);
-ifletOk(binding) = item {
-// The ident resolves to an item.
-returnSome(LexicalScopeBinding::Item(binding));
+ifletRibKind::MacroDefinition(def) = rib.kind
+ && def == self.macro_def(ident.span.ctxt())
+{
+// If an invocation of this macro created `ident`, give up on `ident`
+// and switch to `ident`'s source from the macro definition.
+ ident.span.remove_mark();
 }
 }
-self.cm()
-.early_resolve_ident_in_lexical_scope(
- orig_ident,
-ScopeSet::Late(ns, module, finalize.map(|finalize| finalize.node_id)),
- parent_scope,
- finalize,
- finalize.is_some(),
- ignore_binding,
-None,
-)
-.ok()
-.map(LexicalScopeBinding::Item)
+
+unreachable!()
 }
 
 /// Resolve an identifier in lexical scope.
@@ -1171,6 +1166,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 for rib in ribs {
 match rib.kind{
 RibKind::Normal
+ | RibKind::Block(..)
  | RibKind::FnOrCoroutine
  | RibKind::Module(..)
  | RibKind::MacroDefinition(..)
@@ -1263,6 +1259,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 for rib in ribs {
 let(has_generic_params, def_kind) = match rib.kind{
 RibKind::Normal
+ | RibKind::Block(..)
  | RibKind::FnOrCoroutine
  | RibKind::Module(..)
  | RibKind::MacroDefinition(..)
@@ -1356,6 +1353,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 for rib in ribs {
 let(has_generic_params, def_kind) = match rib.kind{
 RibKind::Normal
+ | RibKind::Block(..)
  | RibKind::FnOrCoroutine
  | RibKind::Module(..)
  | RibKind::MacroDefinition(..)

compiler/rustc_resolve/src/late.rs

@@ -192,6 +192,13 @@ pub(crate) enum RibKind<'ra> {
 /// No restriction needs to be applied.
 Normal,
 
+/// We passed through an `ast::Block`.
+/// Behaves like `Normal`, but also partially like `Module` if the block contains items.
+/// `Block(None)` must be always processed in the same way as `Block(Some(module))`
+/// with empty `module`. The module can be `None` only because creation of some definitely
+/// empty modules is skipped as an optimization.
+Block(Option<Module<'ra>>),
+
 /// We passed through an impl or trait and are now in one of its
 /// methods or associated types. Allow references to ty params that impl or trait
 /// binds. Disallow any other upvars (including other ty params that are
@@ -210,7 +217,7 @@ pub(crate) enum RibKind<'ra> {
 /// All other constants aren't allowed to use generic params at all.
 ConstantItem(ConstantHasGenerics,Option<(Ident,ConstantItemKind)>),
 
-/// We passed through a module.
+/// We passed through a module item.
 Module(Module<'ra>),
 
 /// We passed through a `macro_rules!` statement
@@ -242,6 +249,7 @@ impl RibKind<'_> {
 pub(crate)fncontains_params(&self) -> bool{
 matchself{
 RibKind::Normal
+ | RibKind::Block(..)
  | RibKind::FnOrCoroutine
  | RibKind::ConstantItem(..)
  | RibKind::Module(_)
@@ -258,15 +266,8 @@ impl RibKind<'_> {
 fnis_label_barrier(self) -> bool{
 matchself{
 RibKind::Normal | RibKind::MacroDefinition(..) => false,
-
-RibKind::AssocItem
- | RibKind::FnOrCoroutine
- | RibKind::Item(..)
- | RibKind::ConstantItem(..)
- | RibKind::Module(..)
- | RibKind::ForwardGenericParamBan(_)
- | RibKind::ConstParamTy
- | RibKind::InlineAsmSym => true,
+RibKind::FnOrCoroutine | RibKind::ConstantItem(..) => true,
+ kind => bug!("unexpected rib kind: {kind:?}"),
 }
 }
 }
@@ -1527,19 +1528,6 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
  ret
 }
 
-fnwith_mod_rib<T>(&mutself,id:NodeId,f:implFnOnce(&mutSelf) -> T) -> T{
-let module = self.r.expect_module(self.r.local_def_id(id).to_def_id());
-// Move down in the graph.
-let orig_module = replace(&mutself.parent_scope.module, module);
-self.with_rib(ValueNS,RibKind::Module(module), |this| {
- this.with_rib(TypeNS,RibKind::Module(module), |this| {
-let ret = f(this);
- this.parent_scope.module = orig_module;
- ret
-})
-})
-}
-
 fnvisit_generic_params(&mutself,params:&'ast[GenericParam],add_self_upper:bool){
 // For type parameter defaults, we have to ban access
 // to following type parameters, as the GenericArgs can only
@@ -2677,20 +2665,25 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
 }
 
 ItemKind::Mod(..) => {
-self.with_mod_rib(item.id, |this| {
-if mod_inner_docs {
- this.resolve_doc_links(&item.attrs,MaybeExported::Ok(item.id));
-}
-let old_macro_rules = this.parent_scope.macro_rules;
- visit::walk_item(this, item);
-// Maintain macro_rules scopes in the same way as during early resolution
-// for diagnostics and doc links.
-if item.attrs.iter().all(|attr| {
- !attr.has_name(sym::macro_use) && !attr.has_name(sym::macro_escape)
-}){
- this.parent_scope.macro_rules = old_macro_rules;
-}
+let module = self.r.expect_module(self.r.local_def_id(item.id).to_def_id());
+let orig_module = replace(&mutself.parent_scope.module, module);
+self.with_rib(ValueNS,RibKind::Module(module), |this| {
+ this.with_rib(TypeNS,RibKind::Module(module), |this| {
+if mod_inner_docs {
+ this.resolve_doc_links(&item.attrs,MaybeExported::Ok(item.id));
+}
+let old_macro_rules = this.parent_scope.macro_rules;
+ visit::walk_item(this, item);
+// Maintain macro_rules scopes in the same way as during early resolution
+// for diagnostics and doc links.
+if item.attrs.iter().all(|attr| {
+ !attr.has_name(sym::macro_use) && !attr.has_name(sym::macro_escape)
+}){
+ this.parent_scope.macro_rules = old_macro_rules;
+}
+})
 });
+self.parent_scope.module = orig_module;
 }
 
 ItemKind::Static(box ast::StaticItem{
@@ -2821,9 +2814,9 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
 // We also can't shadow bindings from associated parent items.
 for ns in[ValueNS,TypeNS]{
 for parent_rib inself.ribs[ns].iter().rev(){
-// Break at mod level, to account for nested items which are
+// Break at module or block level, to account for nested items which are
 // allowed to shadow generic param names.
-ifmatches!(parent_rib.kind,RibKind::Module(..)){
+ifmatches!(parent_rib.kind,RibKind::Module(..) | RibKind::Block(..)){
 break;
 }
 
@@ -4652,16 +4645,16 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
 debug!("(resolving block) entering block");
 // Move down in the graph, if there's an anonymous module rooted here.
 let orig_module = self.parent_scope.module;
-let anonymous_module = self.r.block_map.get(&block.id).cloned();// clones a reference
+let anonymous_module = self.r.block_map.get(&block.id).copied();
 
 letmut num_macro_definition_ribs = 0;
 ifletSome(anonymous_module) = anonymous_module {
 debug!("(resolving block) found anonymous module, moving down");
-self.ribs[ValueNS].push(Rib::new(RibKind::Module(anonymous_module)));
-self.ribs[TypeNS].push(Rib::new(RibKind::Module(anonymous_module)));
+self.ribs[ValueNS].push(Rib::new(RibKind::Block(Some(anonymous_module))));
+self.ribs[TypeNS].push(Rib::new(RibKind::Block(Some(anonymous_module))));
 self.parent_scope.module = anonymous_module;
 }else{
-self.ribs[ValueNS].push(Rib::new(RibKind::Normal));
+self.ribs[ValueNS].push(Rib::new(RibKind::Block(None)));
 }
 
 // Descend into the block.

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -849,9 +849,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
 }
 
 // Try to find in last block rib
-ifletSome(rib) = &self.last_block_rib
- && letRibKind::Normal = rib.kind
-{
+ifletSome(rib) = &self.last_block_rib{
 for(ident,&res)in&rib.bindings{
 ifletRes::Local(_) = res
  && path.len() == 1
@@ -900,7 +898,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
 if path.len() == 1{
 for rib inself.ribs[ns].iter().rev(){
 let item = path[0].ident;
-ifletRibKind::Module(module) = rib.kind
+ifletRibKind::Module(module)| RibKind::Block(Some(module))= rib.kind
  && letSome(did) = find_doc_alias_name(self.r, module, item.name)
 {
 returnSome((did, item));
@@ -2458,9 +2456,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
 }
 }
 
-ifletRibKind::Module(module) = rib.kind
- && letModuleKind::Block = module.kind
-{
+ifletRibKind::Block(Some(module)) = rib.kind{
 self.r.add_module_candidates(module,&mut names,&filter_fn,Some(ctxt));
 }elseifletRibKind::Module(module) = rib.kind{
 // Encountered a module item, abandon ribs and look into that module and preludes.

tests/ui/resolve/issue-104700-inner_scope.rs

@@ -7,5 +7,12 @@ fn main() {
 if bar == 2{//~ ERROR cannot find value
 println!("yes");
 }
+{
+let baz = 3;
+structS;
+}
+if baz == 3{//~ ERROR cannot find value
+println!("yes");
+}
 test_func(1);//~ ERROR cannot find function
 }

tests/ui/resolve/issue-104700-inner_scope.stderr

@@ -10,12 +10,24 @@ help: the binding `bar` is available in a different scope in the same function
 LL | let bar = 2;
  | ^^^
 
+error[E0425]: cannot find value `baz` in this scope
+ --> $DIR/issue-104700-inner_scope.rs:14:8
+ |
+LL | if baz == 3 {
+ | ^^^
+ |
+help: the binding `baz` is available in a different scope in the same function
+ --> $DIR/issue-104700-inner_scope.rs:11:13
+ |
+LL | let baz = 3;
+ | ^^^
+
 error[E0425]: cannot find function `test_func` in this scope
- --> $DIR/issue-104700-inner_scope.rs:10:5
+ --> $DIR/issue-104700-inner_scope.rs:17:5
  |
 LL | test_func(1);
  | ^^^^^^^^^ not found in this scope
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0425`.