[clang] [clang][ASTImporter] fix variable inline of CXX17 (PR #87314)

[Qizhi Hu via cfe-commits]

https://github.com/jcsxky created https://github.com/llvm/llvm-project/pull/87314

Fix crash int the testcase from https://github.com/llvm/llvm-project/issues/75114#issuecomment-1872595956
Forget to set inline of variable declaration would make `isThisDeclarationADefinition` get incorrect result and didn't get imported variable. This will lead to a new `VarTemplateDecl` being created and call `setDescribedVarTemplate` again which produce the crash.

>From 2f579346d6955e06d8e16bb29467ed5da332451d Mon Sep 17 00:00:00 2001
From: huqizhi <huqizhi at feysh.com>
Date: Tue, 2 Apr 2024 13:18:14 +0800
Subject: [PATCH] [clang][ASTImporter] fix variable inline of CXX17

---
 clang/lib/AST/ASTImporter.cpp           |  9 ++++++--
 clang/unittests/AST/ASTImporterTest.cpp | 28 +++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 94a47a8f619018..cfdb2cb5c778e3 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -4579,7 +4579,12 @@ ExpectedDecl ASTNodeImporter::VisitVarDecl(VarDecl *D) {
     if (!RedeclOrErr)
       return RedeclOrErr.takeError();
   }
-
+  if (D->isInlineSpecified()) {
+    ToVar->setInlineSpecified();
+  }
+  if (D->isInline()) {
+    ToVar->setImplicitlyInline();
+  }
   return ToVar;
 }
 
@@ -6410,7 +6415,7 @@ ExpectedDecl ASTNodeImporter::VisitVarTemplateDecl(VarTemplateDecl *D) {
     }
     ToVarTD->setPreviousDecl(Recent);
   }
-
+  // Importer.MapImported(D, ToVarTD);
   return ToVarTD;
 }
 
diff --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 35ab7e3b7fe314..d57736830f0223 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -5317,6 +5317,34 @@ TEST_P(ASTImporterOptionSpecificTestBase,
   EXPECT_FALSE(ToX);
 }
 
+TEST_P(ASTImporterOptionSpecificTestBase, VarTemplateDeclInlineWithCXX17) {
+  Decl *FromTU = getTuDecl(
+      R"(
+      struct S {
+        template <unsigned> static constexpr bool X = true;
+      };
+      )",
+      Lang_CXX17, "input1.cc");
+  Decl *FromTU2 = getTuDecl(
+      R"(
+      struct S {
+        template <unsigned> static constexpr bool X = true;
+        template <typename T> void get() { X<sizeof(T)>; }
+      };
+      template <typename T> T qvariant_cast(const S &v) { return v.get; }
+      )",
+      Lang_CXX17, "input2.cc");
+  auto *FromX = FirstDeclMatcher<VarTemplateDecl>().match(
+      FromTU, varTemplateDecl(hasName("X")));
+  auto *ToX = Import(FromX, Lang_CXX17);
+  EXPECT_TRUE(ToX);
+  auto *FromX2 = FirstDeclMatcher<VarTemplateDecl>().match(
+      FromTU2, varTemplateDecl(hasName("X")));
+  auto *ToX2 = Import(FromX2, Lang_CXX17);
+  EXPECT_TRUE(ToX2);
+  EXPECT_TRUE(ToX == ToX2);
+}
+
 TEST_P(ASTImporterOptionSpecificTestBase, VarTemplateParameterDeclContext) {
   constexpr auto Code =
       R"(