[clang] da2b415 - [clang] Add tracking source deduction guide for the explicitly-written

[Haojian Wu via cfe-commits]

Author: Haojian Wu
Date: 2025-02-02T23:06:25+01:00
New Revision: da2b415b19d178d6b250bb6468ed4a207860adf7

URL: https://github.com/llvm/llvm-project/commit/da2b415b19d178d6b250bb6468ed4a207860adf7
DIFF: https://github.com/llvm/llvm-project/commit/da2b415b19d178d6b250bb6468ed4a207860adf7.diff

LOG: [clang] Add tracking source deduction guide for the explicitly-written
deduction guide.

We miss this case in the original f94c481543bdd3b11a668ad78d46593cf974788f commit.

Added: 
    

Modified: 
    clang/lib/Sema/SemaTemplateDeductionGuide.cpp
    clang/unittests/AST/ASTImporterTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp
index 63592c335d211be..0d079677eecc568 100644
--- a/clang/lib/Sema/SemaTemplateDeductionGuide.cpp
+++ b/clang/lib/Sema/SemaTemplateDeductionGuide.cpp
@@ -1227,11 +1227,14 @@ void DeclareImplicitDeductionGuidesForTypeAlias(
         NewParam->setScopeInfo(0, I);
         FPTL.setParam(I, NewParam);
       }
-      auto *Transformed = cast<FunctionDecl>(buildDeductionGuide(
+      auto *Transformed = cast<CXXDeductionGuideDecl>(buildDeductionGuide(
           SemaRef, AliasTemplate, /*TemplateParams=*/nullptr,
           /*Constructor=*/nullptr, DG->getExplicitSpecifier(), FunctionType,
           AliasTemplate->getBeginLoc(), AliasTemplate->getLocation(),
           AliasTemplate->getEndLoc(), DG->isImplicit()));
+      Transformed->setSourceDeductionGuide(DG);
+      Transformed->setSourceDeductionGuideKind(
+          CXXDeductionGuideDecl::SourceDeductionGuideKind::Alias);
 
       // FIXME: Here the synthesized deduction guide is not a templated
       // function. Per [dcl.decl]p4, the requires-clause shall be present only

diff  --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 114d0b461dae880..0bac95eb40b2096 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -8193,6 +8193,29 @@ TEST_P(ImportFunctions, CTADAliasTemplate) {
   EXPECT_TRUE(ToD->getSourceDeductionGuide());
 }
 
+TEST_P(ImportFunctions, CTADAliasTemplateWithExplicitSourceDeductionGuide) {
+  Decl *TU = getTuDecl(
+      R"(
+      template <typename T> struct A {
+        A(T);
+      };
+      template<typename T>
+      using B = A<T>;
+      A(int) -> A<double>; // explicit
+      B b{(int)0};
+      )",
+      Lang_CXX20, "input.cc");
+  auto *FromD = FirstDeclMatcher<CXXDeductionGuideDecl>().match(
+      TU, cxxDeductionGuideDecl(hasParameter(0, hasType(asString("int"))),
+                                hasName("<deduction guide for B>"),
+                                hasReturnTypeLoc(loc(asString("A<double>")))));
+  auto *ToD = Import(FromD, Lang_CXX20);
+  ASSERT_TRUE(ToD);
+  EXPECT_TRUE(ToD->getSourceDeductionGuideKind() ==
+              CXXDeductionGuideDecl::SourceDeductionGuideKind::Alias);
+  EXPECT_TRUE(ToD->getSourceDeductionGuide());
+}
+
 TEST_P(ImportFunctions, ParmVarDeclDeclContext) {
   constexpr auto FromTUCode = R"(
       void f(int P);