Fix IDE layer not correctly resolving opt-in extern crates

Author: Veykril

src/tools/rust-analyzer/crates/hir-def/src/data.rs

@@ -506,14 +506,17 @@ impl ExternCrateDeclData {
         let crate_id = if name == sym::self_.clone() {
             Some(krate)
         } else {
-            db.crate_def_map(krate)
-                .extern_prelude()
-                .find(|&(prelude_name, ..)| *prelude_name == name)
-                .map(|(_, (root, _))| root.krate())
+            db.crate_graph()[krate].dependencies.iter().find_map(|dep| {
+                if dep.name.symbol() == name.symbol() {
+                    Some(dep.crate_id)
+                } else {
+                    None
+                }
+            })
         };
 
         Arc::new(Self {
-            name: extern_crate.name.clone(),
+            name,
             visibility: item_tree[extern_crate.visibility].clone(),
             alias: extern_crate.alias.clone(),
             crate_id,

src/tools/rust-analyzer/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html

@@ -49,5 +49,8 @@
 <span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">std</span><span class="semicolon">;</span>
 <span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">alloc</span> <span class="keyword">as</span> <span class="module crate_root declaration">abc</span><span class="semicolon">;</span>
 <span class="keyword">extern</span> <span class="keyword">crate</span> <span class="unresolved_reference">unresolved</span> <span class="keyword">as</span> <span class="module crate_root declaration">definitely_unresolved</span><span class="semicolon">;</span>
-<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="unresolved_reference">test</span> <span class="keyword">as</span> <span class="module crate_root declaration">opt_in_crate</span><span class="semicolon">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="unresolved_reference">unresolved</span> <span class="keyword">as</span> <span class="punctuation">_</span><span class="semicolon">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">test</span> <span class="keyword">as</span> <span class="module crate_root declaration">opt_in_crate</span><span class="semicolon">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">test</span> <span class="keyword">as</span> <span class="punctuation">_</span><span class="semicolon">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">proc_macro</span><span class="semicolon">;</span>
 </code></pre>

src/tools/rust-analyzer/crates/ide/src/syntax_highlighting/tests.rs

@@ -874,18 +874,23 @@ pub fn block_comments2() {}
 fn test_extern_crate() {
     check_highlighting(
         r#"
-//- /main.rs crate:main deps:std,alloc,test extern-prelude:std,alloc
+//- /main.rs crate:main deps:std,alloc,test,proc_macro extern-prelude:std,alloc
 extern crate self as this;
 extern crate std;
 extern crate alloc as abc;
 extern crate unresolved as definitely_unresolved;
+extern crate unresolved as _;
 extern crate test as opt_in_crate;
+extern crate test as _;
+extern crate proc_macro;
 //- /std/lib.rs crate:std
 pub struct S;
 //- /alloc/lib.rs crate:alloc
 pub struct A;
 //- /test/lib.rs crate:test
 pub struct T;
+//- /proc_macro/lib.rs crate:proc_macro
+pub struct ProcMacro;
 "#,
         expect_file!["./test_data/highlight_extern_crate.html"],
         false,