From 882ae7105dc9a29dca14c5dc7a0c39c34d33ef0d Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Sun, 30 Jun 2024 13:26:13 +0200
Subject: [PATCH] Simplify unresolved proc-macro handling

---
 crates/hir-def/src/data.rs                |  4 --
 crates/hir-def/src/nameres/collector.rs   | 14 ++----
 crates/hir-def/src/nameres/diagnostics.rs | 55 +++++++++++++++++------
 3 files changed, 44 insertions(+), 29 deletions(-)

diff --git a/crates/hir-def/src/data.rs b/crates/hir-def/src/data.rs
index 8cf1e15f31..55043fdc4b 100644
--- a/crates/hir-def/src/data.rs
+++ b/crates/hir-def/src/data.rs
@@ -637,10 +637,6 @@ impl<'a> AssocItemCollector<'a> {
                     attr,
                 ) {
                     Ok(ResolvedAttr::Macro(call_id)) => {
-                        // If proc attribute macro expansion is disabled, skip expanding it here
-                        if !self.db.expand_proc_attr_macros() {
-                            continue 'attrs;
-                        }
                         let loc = self.db.lookup_intern_macro_call(call_id);
                         if let MacroDefKind::ProcMacro(_, exp, _) = loc.def.kind {
                             // If there's no expander for the proc macro (e.g. the
diff --git a/crates/hir-def/src/nameres/collector.rs b/crates/hir-def/src/nameres/collector.rs
index 6d2eb71549..b5045efb62 100644
--- a/crates/hir-def/src/nameres/collector.rs
+++ b/crates/hir-def/src/nameres/collector.rs
@@ -83,7 +83,9 @@ pub(super) fn collect_defs(db: &dyn DefDatabase, def_map: DefMap, tree_id: TreeI
                     let name = Name::new_text_dont_use(it.name.clone());
                     (
                         name,
-                        if it.disabled {
+                        if !db.expand_proc_attr_macros() {
+                            CustomProcMacroExpander::dummy()
+                        } else if it.disabled {
                             CustomProcMacroExpander::disabled()
                         } else {
                             CustomProcMacroExpander::new(hir_expand::proc_macro::ProcMacroId::new(
@@ -1331,16 +1333,6 @@ impl DefCollector<'_> {
 
                     let call_id = call_id();
                     if let MacroDefKind::ProcMacro(_, exp, _) = def.kind {
-                        // If proc attribute macro expansion is disabled, skip expanding it here
-                        if !self.db.expand_proc_attr_macros() {
-                            self.def_map.diagnostics.push(DefDiagnostic::unresolved_proc_macro(
-                                directive.module_id,
-                                self.db.lookup_intern_macro_call(call_id).kind,
-                                def.krate,
-                            ));
-                            return recollect_without(self);
-                        }
-
                         // If there's no expander for the proc macro (e.g.
                         // because proc macros are disabled, or building the
                         // proc macro crate failed), report this and skip
diff --git a/crates/hir-def/src/nameres/diagnostics.rs b/crates/hir-def/src/nameres/diagnostics.rs
index 523a4c107b..4ab53d20b5 100644
--- a/crates/hir-def/src/nameres/diagnostics.rs
+++ b/crates/hir-def/src/nameres/diagnostics.rs
@@ -17,16 +17,47 @@ use crate::{
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum DefDiagnosticKind {
-    UnresolvedModule { ast: AstId<ast::Module>, candidates: Box<[String]> },
-    UnresolvedExternCrate { ast: AstId<ast::ExternCrate> },
-    UnresolvedImport { id: ItemTreeId<item_tree::Use>, index: Idx<ast::UseTree> },
-    UnconfiguredCode { ast: ErasedAstId, cfg: CfgExpr, opts: CfgOptions },
-    UnresolvedProcMacro { ast: MacroCallKind, krate: CrateId },
-    UnresolvedMacroCall { ast: MacroCallKind, path: ModPath },
-    UnimplementedBuiltinMacro { ast: AstId<ast::Macro> },
-    InvalidDeriveTarget { ast: AstId<ast::Item>, id: usize },
-    MalformedDerive { ast: AstId<ast::Adt>, id: usize },
-    MacroDefError { ast: AstId<ast::Macro>, message: String },
+    UnresolvedModule {
+        ast: AstId<ast::Module>,
+        candidates: Box<[String]>,
+    },
+    UnresolvedExternCrate {
+        ast: AstId<ast::ExternCrate>,
+    },
+    UnresolvedImport {
+        id: ItemTreeId<item_tree::Use>,
+        index: Idx<ast::UseTree>,
+    },
+    UnconfiguredCode {
+        ast: ErasedAstId,
+        cfg: CfgExpr,
+        opts: CfgOptions,
+    },
+    /// A proc-macro that is lacking an expander, this might be due to build scripts not yet having
+    /// run or proc-macro expansion being disabled.
+    UnresolvedProcMacro {
+        ast: MacroCallKind,
+        krate: CrateId,
+    },
+    UnresolvedMacroCall {
+        ast: MacroCallKind,
+        path: ModPath,
+    },
+    UnimplementedBuiltinMacro {
+        ast: AstId<ast::Macro>,
+    },
+    InvalidDeriveTarget {
+        ast: AstId<ast::Item>,
+        id: usize,
+    },
+    MalformedDerive {
+        ast: AstId<ast::Adt>,
+        id: usize,
+    },
+    MacroDefError {
+        ast: AstId<ast::Macro>,
+        message: String,
+    },
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -92,10 +123,6 @@ impl DefDiagnostic {
         Self { in_module: container, kind: DefDiagnosticKind::UnconfiguredCode { ast, cfg, opts } }
     }
 
-    // FIXME: Whats the difference between this and unresolved_macro_call
-    // FIXME: This is used for a lot of things, unresolved proc macros, disabled proc macros, etc
-    // yet the diagnostic handler in ide-diagnostics has to figure out what happened because this
-    // struct loses all that information!
     pub fn unresolved_proc_macro(
         container: LocalModuleId,
         ast: MacroCallKind,