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//===--- ExpectedTypes.cpp ---------------------------------------*- C++-*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "ExpectedTypes.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Type.h"
#include "clang/Index/USRGeneration.h"
#include "clang/Sema/CodeCompleteConsumer.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/STLExtras.h"
namespace clang {
namespace clangd {
namespace {
static const Type *toEquivClass(ASTContext &Ctx, QualType T) {
if (T.isNull() || T->isDependentType())
return nullptr;
// Drop references, we do not handle reference inits properly anyway.
T = T.getCanonicalType().getNonReferenceType();
// Numeric types are the simplest case.
if (T->isBooleanType())
return Ctx.BoolTy.getTypePtr();
if (T->isIntegerType() && !T->isEnumeralType())
return Ctx.IntTy.getTypePtr(); // All integers are equivalent.
if (T->isFloatingType() && !T->isComplexType())
return Ctx.FloatTy.getTypePtr(); // All floats are equivalent.
// Do some simple transformations.
if (T->isArrayType()) // Decay arrays to pointers.
return Ctx.getPointerType(QualType(T->getArrayElementTypeNoTypeQual(), 0))
// Drop the qualifiers and return the resulting type.
// FIXME: also drop qualifiers from pointer types, e.g. 'const T* => T*'
return T.getTypePtr();
static llvm::Optional<QualType>
typeOfCompletion(const CodeCompletionResult &R) {
const NamedDecl *D = R.Declaration;
// Templates do not have a type on their own, look at the templated decl.
if (auto *Template = dyn_cast_or_null<TemplateDecl>(D))
D = Template->getTemplatedDecl();
auto *VD = dyn_cast_or_null<ValueDecl>(D);
if (!VD)
return llvm::None; // We handle only variables and functions below.
auto T = VD->getType();
if (T.isNull())
return llvm::None;
if (auto FuncT = T->getAs<FunctionType>()) {
// Functions are a special case. They are completed as 'foo()' and we want
// to match their return type rather than the function type itself.
// FIXME(ibiryukov): in some cases, we might want to avoid completing `()`
// after the function name, e.g. `std::cout << std::endl`.
return FuncT->getReturnType();
return T;
} // namespace
llvm::Optional<OpaqueType> OpaqueType::encode(ASTContext &Ctx, QualType T) {
if (T.isNull())
return None;
const Type *C = toEquivClass(Ctx, T);
if (!C)
return None;
llvm::SmallString<128> Encoded;
if (index::generateUSRForType(QualType(C, 0), Ctx, Encoded))
return None;
return OpaqueType(std::string(Encoded.str()));
OpaqueType::OpaqueType(std::string Data) : Data(std::move(Data)) {}
llvm::Optional<OpaqueType> OpaqueType::fromType(ASTContext &Ctx,
QualType Type) {
return encode(Ctx, Type);
OpaqueType::fromCompletionResult(ASTContext &Ctx,
const CodeCompletionResult &R) {
auto T = typeOfCompletion(R);
if (!T)
return None;
return encode(Ctx, *T);
} // namespace clangd
} // namespace clang