Unverified Commit a31a61da authored by Kadir Cetinkaya's avatar Kadir Cetinkaya
Browse files

[clangd][Hover] Handle uninstantiated templates 

Summary: Fixes https://github.com/clangd/clangd/issues/263

Reviewers: hokein, sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D73344
parent f4871ead

clang-tools-extra/clangd/Hover.cpp

+18 −9
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include "clang/AST/ExprCXX.h"

#include "clang/AST/PrettyPrinter.h"

#include "clang/AST/Type.h"

#include "clang/Basic/Specifiers.h"

#include "clang/Index/IndexSymbol.h"

#include "llvm/ADT/None.h"

#include "llvm/ADT/Optional.h"
@@ -205,15 +206,23 @@ const FunctionDecl *getUnderlyingFunction(const Decl *D) { 
// Returns the decl that should be used for querying comments, either from index

// or AST.

const NamedDecl *getDeclForComment(const NamedDecl *D) {

  if (auto *CTSD = llvm::dyn_cast<ClassTemplateSpecializationDecl>(D))

    if (!CTSD->isExplicitInstantiationOrSpecialization())

      return CTSD->getTemplateInstantiationPattern();

  if (auto *VTSD = llvm::dyn_cast<VarTemplateSpecializationDecl>(D))

    if (!VTSD->isExplicitInstantiationOrSpecialization())

      return VTSD->getTemplateInstantiationPattern();

  if (auto *FD = D->getAsFunction())

    if (FD->isTemplateInstantiation())

      return FD->getTemplateInstantiationPattern();

  if (const auto *TSD = llvm::dyn_cast<ClassTemplateSpecializationDecl>(D)) {

    // Template may not be instantiated e.g. if the type didn't need to be

    // complete; fallback to primary template.

    if (TSD->getTemplateSpecializationKind() == TSK_Undeclared)

      return TSD->getSpecializedTemplate();

    if (const auto *TIP = TSD->getTemplateInstantiationPattern())

      return TIP;

  }

  if (const auto *TSD = llvm::dyn_cast<VarTemplateSpecializationDecl>(D)) {

    if (TSD->getTemplateSpecializationKind() == TSK_Undeclared)

      return TSD->getSpecializedTemplate();

    if (const auto *TIP = TSD->getTemplateInstantiationPattern())

      return TIP;

  }

  if (const auto *FD = D->getAsFunction())

    if (const auto *TIP = FD->getTemplateInstantiationPattern())

      return TIP;

  return D;

}

clang-tools-extra/clangd/unittests/HoverTests.cpp

+19 −0
Original line number Diff line number Diff line
@@ -554,6 +554,25 @@ class Foo {})cpp"; 
            HI.Name = "Foo<X>";

            HI.Kind = index::SymbolKind::Class;

          }},

      {// Falls back to primary template, when the type is not instantiated.

       R"cpp(

          // comment from primary

          template <typename T> class Foo {};

          // comment from specialization

          template <typename T> class Foo<T*> {};

          void foo() {

            [[Fo^o]]<int*> *x = nullptr;

          }

          )cpp",

       [](HoverInfo &HI) {

         HI.Name = "Foo<int *>";

         HI.Kind = index::SymbolKind::Class;

         HI.NamespaceScope = "";

         HI.Definition = "template <> class Foo<int *>";

         // FIXME: Maybe force instantiation to make use of real template

         // pattern.

         HI.Documentation = "comment from primary";

       }},

  };

  for (const auto &Case : Cases) {

    SCOPED_TRACE(Case.Code);