[clang] [Clang][Sema] Check the number of lambda non-concept tempate parameters (PR #74885)

[via cfe-commits]

https://github.com/knightXun updated https://github.com/llvm/llvm-project/pull/74885

>From 12cc1fe332fbab94c1368ea95374d5a1289a22f8 Mon Sep 17 00:00:00 2001
From: knightXun <badgangkiller at gmail.com>
Date: Sat, 9 Dec 2023 04:57:15 +0800
Subject: [PATCH] [Clang][Sema] Check the number of lambda non-concept tempate
 parameters Check that the number of non-concept template parameters is
 greater than zero during lambda template instantiation to aviod panic Fix
 issue: https://github.com/llvm/llvm-project/issues/70601

---
 .../include/clang/Basic/DiagnosticParseKinds.td  |  2 ++
 clang/lib/Sema/TreeTransform.h                   | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 6150fc36430ab1..e46fa69d013b61 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -851,6 +851,8 @@ def err_friend_explicit_instantiation : Error<
 def err_explicit_instantiation_enum : Error<
   "enumerations cannot be explicitly instantiated">;
 def err_expected_template_parameter : Error<"expected template parameter">;
+def err_expected_non_concept_template_parameter : Error<
+  "expected non-concept template parameter">;
 def err_empty_requires_expr : Error<
   "a requires expression must contain at least one requirement">;
 def err_requires_expr_parameter_list_ellipsis : Error<
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 1ad843d0bf4e0c..a140bbbc0c43d5 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -13662,6 +13662,22 @@ TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
     return ExprError();
   }
 
+  // Check the number of the Concept template parameters
+  size_t conceptParams = 0;
+  for (auto P : *E->getTemplateParameterList()) {
+    const TemplateTypeParmDecl *CD = dyn_cast<TemplateTypeParmDecl>(P);
+    if (CD && CD->hasTypeConstraint()) {
+      conceptParams++;
+    }
+  }
+
+  if (conceptParams > 0 &&
+      conceptParams == E->getTemplateParameterList()->size()) {
+    getSema().Diag(E->getTemplateParameterList()->getLAngleLoc(),
+                   diag::err_expected_non_concept_template_parameter);
+    return ExprError();
+  }
+
   // Copy the LSI before ActOnFinishFunctionBody removes it.
   // FIXME: This is dumb. Store the lambda information somewhere that outlives
   // the call operator.