llvm-project/clang/unittests/Tooling/CastExprTest.cpp

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//===- unittest/Tooling/CastExprTest.cpp ----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "TestVisitor.h"
using namespace clang;
namespace {
struct CastExprVisitor : TestVisitor<CastExprVisitor> {
std::function<void(ExplicitCastExpr *)> OnExplicitCast;
std::function<void(CastExpr *)> OnCast;
bool VisitExplicitCastExpr(ExplicitCastExpr *Expr) {
if (OnExplicitCast)
OnExplicitCast(Expr);
return true;
}
bool VisitCastExpr(CastExpr *Expr) {
if (OnCast)
OnCast(Expr);
return true;
}
};
TEST(CastExprTest, GetSubExprAsWrittenThroughMaterializedTemporary) {
CastExprVisitor Visitor;
Visitor.OnExplicitCast = [](ExplicitCastExpr *Expr) {
auto Sub = Expr->getSubExprAsWritten();
EXPECT_TRUE(isa<DeclRefExpr>(Sub))
<< "Expected DeclRefExpr, but saw " << Sub->getStmtClassName();
};
Visitor.runOver("struct S1 {};\n"
"struct S2 { operator S1(); };\n"
"S1 f(S2 s) { return static_cast<S1>(s); }\n");
}
// Verify that getSubExprAsWritten looks through a ConstantExpr in a scenario
// like
//
// CXXFunctionalCastExpr functional cast to struct S <ConstructorConversion>
// `-ConstantExpr 'S'
// |-value: Struct
// `-CXXConstructExpr 'S' 'void (int)'
// `-IntegerLiteral 'int' 0
TEST(CastExprTest, GetSubExprAsWrittenThroughConstantExpr) {
CastExprVisitor Visitor;
Visitor.OnExplicitCast = [](ExplicitCastExpr *Expr) {
auto *Sub = Expr->getSubExprAsWritten();
EXPECT_TRUE(isa<IntegerLiteral>(Sub))
<< "Expected IntegerLiteral, but saw " << Sub->getStmtClassName();
};
Visitor.runOver("struct S { consteval S(int) {} };\n"
"S f() { return S(0); }\n",
CastExprVisitor::Lang_CXX2a);
}
// Verify that getConversionFunction looks through a ConstantExpr for implicit
// constructor conversions (https://github.com/llvm/llvm-project/issues/53044):
//
// `-ImplicitCastExpr 'X' <ConstructorConversion>
// `-ConstantExpr 'X'
// |-value: Struct
// `-CXXConstructExpr 'X' 'void (const char *)'
// `-ImplicitCastExpr 'const char *' <ArrayToPointerDecay>
// `-StringLiteral 'const char [7]' lvalue "foobar"
TEST(CastExprTest, GetCtorConversionFunctionThroughConstantExpr) {
CastExprVisitor Visitor;
Visitor.OnCast = [](CastExpr *Expr) {
if (Expr->getCastKind() == CK_ConstructorConversion) {
auto *Conv = Expr->getConversionFunction();
EXPECT_TRUE(isa<CXXConstructorDecl>(Conv))
<< "Expected CXXConstructorDecl, but saw " << Conv->getDeclKindName();
}
};
Visitor.runOver("struct X { consteval X(const char *) {} };\n"
"void f() { X x = \"foobar\"; }\n",
CastExprVisitor::Lang_CXX2a);
}
// Verify that getConversionFunction looks through a ConstantExpr for implicit
// user-defined conversions.
//
// `-ImplicitCastExpr 'const char *' <UserDefinedConversion>
// `-ConstantExpr 'const char *'
// |-value: LValue
// `-CXXMemberCallExpr 'const char *'
// `-MemberExpr '<bound member function type>' .operator const char *
// `-DeclRefExpr 'const X' lvalue Var 'x' 'const X'
TEST(CastExprTest, GetUserDefinedConversionFunctionThroughConstantExpr) {
CastExprVisitor Visitor;
Visitor.OnCast = [](CastExpr *Expr) {
if (Expr->getCastKind() == CK_UserDefinedConversion) {
auto *Conv = Expr->getConversionFunction();
EXPECT_TRUE(isa<CXXMethodDecl>(Conv))
<< "Expected CXXMethodDecl, but saw " << Conv->getDeclKindName();
}
};
Visitor.runOver("struct X {\n"
" consteval operator const char *() const {\n"
" return nullptr;\n"
" }\n"
"};\n"
"const char *f() {\n"
" constexpr X x;\n"
" return x;\n"
"}\n",
CastExprVisitor::Lang_CXX2a);
}
} // namespace