[clang] [clang][ExtractAPI] emit correct spelling for type aliases (PR #134007)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Erick Velez (evelez7)

<details>
<summary>Changes</summary>

Previously, C++11 type aliases were serialized using "typedef" regardless of the source spelling.
This checks if the TypedefNameDecl is actually a TypeAliasDecl and corrects the spelling.

---
Full diff: https://github.com/llvm/llvm-project/pull/134007.diff


2 Files Affected:

- (modified) clang/lib/ExtractAPI/DeclarationFragments.cpp (+19-7) 
- (added) clang/test/ExtractAPI/type-alias.cpp (+56) 


``````````diff
diff --git a/clang/lib/ExtractAPI/DeclarationFragments.cpp b/clang/lib/ExtractAPI/DeclarationFragments.cpp
index d7eebcbc3c2f9..80174e30ffd1a 100644
--- a/clang/lib/ExtractAPI/DeclarationFragments.cpp
+++ b/clang/lib/ExtractAPI/DeclarationFragments.cpp
@@ -1584,13 +1584,25 @@ DeclarationFragments DeclarationFragmentsBuilder::getFragmentsForObjCProtocol(
 DeclarationFragments DeclarationFragmentsBuilder::getFragmentsForTypedef(
     const TypedefNameDecl *Decl) {
   DeclarationFragments Fragments, After;
-  Fragments.append("typedef", DeclarationFragments::FragmentKind::Keyword)
-      .appendSpace()
-      .append(getFragmentsForType(Decl->getUnderlyingType(),
-                                  Decl->getASTContext(), After))
-      .append(std::move(After))
-      .appendSpace()
-      .append(Decl->getName(), DeclarationFragments::FragmentKind::Identifier);
+  if (!isa<TypeAliasDecl>(Decl))
+    Fragments.append("typedef", DeclarationFragments::FragmentKind::Keyword)
+        .appendSpace()
+        .append(getFragmentsForType(Decl->getUnderlyingType(),
+                                    Decl->getASTContext(), After))
+        .append(std::move(After))
+        .appendSpace()
+        .append(Decl->getName(),
+                DeclarationFragments::FragmentKind::Identifier);
+  else
+    Fragments.append("using", DeclarationFragments::FragmentKind::Keyword)
+        .appendSpace()
+        .append(Decl->getName(), DeclarationFragments::FragmentKind::Identifier)
+        .appendSpace()
+        .append("=", DeclarationFragments::FragmentKind::Text)
+        .appendSpace()
+        .append(getFragmentsForType(Decl->getUnderlyingType(),
+                                    Decl->getASTContext(), After))
+        .append(std::move(After));
 
   return Fragments.appendSemicolon();
 }
diff --git a/clang/test/ExtractAPI/type-alias.cpp b/clang/test/ExtractAPI/type-alias.cpp
new file mode 100644
index 0000000000000..246e8fbb92156
--- /dev/null
+++ b/clang/test/ExtractAPI/type-alias.cpp
@@ -0,0 +1,56 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -extract-api --pretty-sgf --emit-sgf-symbol-labels-for-testing \
+// RUN:   --product-name=TypeAlias -triple arm64-apple-macosx -x c++-header %s -o %t/type-alias.symbols.json -verify
+
+// RUN: FileCheck %s --input-file %t/type-alias.symbols.json --check-prefix MYALIAS
+using MyAlias = int;
+//MYALIAS-LABEL "!testLabel": "c:@MYALIAS"
+//MYALIAS:       "accessLevel": "public",
+//MYALIAS:       "declarationFragments": [
+//MYALIAS-NEXT:    {
+//MYALIAS-NEXT:      "kind": "keyword",
+//MYALIAS-NEXT:      "spelling": "using"
+//MYALIAS-NEXT:    },
+//MYALIAS-NEXT:    {
+//MYALIAS-NEXT:      "kind": "text",
+//MYALIAS-NEXT:      "spelling": " "
+//MYALIAS-NEXT:    },
+//MYALIAS-NEXT:    {
+//MYALIAS-NEXT:      "kind": "identifier",
+//MYALIAS-NEXT:      "spelling": "MyAlias"
+//MYALIAS-NEXT:    },
+//MYALIAS-NEXT:    {
+//MYALIAS-NEXT:      "kind": "text",
+//MYALIAS-NEXT:      "spelling": " = "
+//MYALIAS-NEXT:    },
+//MYALIAS-NEXT:    {
+//MYALIAS-NEXT:      "kind": "typeIdentifier",
+//MYALIAS-NEXT:      "preciseIdentifier": "c:I",
+//MYALIAS-NEXT:      "spelling": "int"
+//MYALIAS-NEXT:    },
+//MYALIAS-NEXT:    {
+//MYALIAS-NEXT:      "kind": "text",
+//MYALIAS-NEXT:      "spelling": ";"
+//MYALIAS-NEXT:    }
+//MYALIAS:       "kind": {
+//MYALIAS-NEXT:      "displayName": "Type Alias",
+//MYALIAS-NEXT:      "identifier": "c++.typealias"
+//MYALIAS:       names": {
+//MYALIAS-NEXT:    "navigator": [
+//MYALIAS-NEXT:      {
+//MYALIAS-NEXT:        "kind": "identifier",
+//MYALIAS-NEXT:        "spelling": "MyAlias"
+//MYALIAS-NEXT:      }
+//MYALIAS-NEXT:    ],
+//MYALIAS-NEXT:      "subHeading": [
+//MYALIAS-NEXT:        {
+//MYALIAS-NEXT:          "kind": "identifier",
+//MYALIAS-NEXT:          "spelling": "MyAlias"
+//MYALIAS-NEXT:        }
+//MYALIAS-NEXT:    ],
+//MYALIAS-NEXT:    "title": "MyAlias"
+//MYALIAS:       "pathComponents": [
+//MYALIAS-NEXT:    "MyAlias"
+//MYALIAS-NEXT:  ]
+
+// expected-no-diagnostics
\ No newline at end of file

``````````

</details>


https://github.com/llvm/llvm-project/pull/134007