[clang] [C++26] [Contracts] Initial parser support (PR #221139)

[Chuanqi Xu via cfe-commits]

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@@ -2591,21 +2592,30 @@ bool Parser::ParseCXXMemberDeclaratorBeforeInitializer(
     BitfieldSize = ParseConstantExpression();
     if (BitfieldSize.isInvalid())
       SkipUntil(tok::comma, StopAtSemi | StopBeforeMatch);
-  } else if (Tok.is(tok::kw_requires)) {
-    TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
-    // With abbreviated function templates - we need to explicitly add depth to
-    // account for the implicit template parameter list induced by the template.
-    if (DeclaratorInfo.getTemplateParameterLists().empty() &&
-        DeclaratorInfo.getInventedTemplateParameterList())
-      ++CurTemplateDepthTracker;
-    ParseTrailingRequiresClauseWithScope(DeclaratorInfo);
   } else {
-    ParseOptionalCXX11VirtSpecifierSeq(
-        VS, getCurrentClass().IsInterface,
-        DeclaratorInfo.getDeclSpec().getFriendSpecLoc());
-    if (!VS.isUnset())
-      MaybeParseAndDiagnoseDeclSpecAfterCXX11VirtSpecifierSeq(DeclaratorInfo,
-                                                              VS);
+    // Requires clause can't follow 'override' but contracts can follow
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ChuanqiXu9 wrote:

Done by adding tests for `then`  and `requires `. For `override`, I didn't add as I plan to support it (emit the diagnostic) later.

https://github.com/llvm/llvm-project/pull/221139