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      1 //===- unittests/ErrorOrTest.cpp - ErrorOr.h tests ------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "llvm/Support/ErrorOr.h"
     11 #include "llvm/Support/Errc.h"
     12 #include "gtest/gtest.h"
     13 #include <memory>
     14 
     15 using namespace llvm;
     16 
     17 namespace {
     18 
     19 ErrorOr<int> t1() { return 1; }
     20 ErrorOr<int> t2() { return errc::invalid_argument; }
     21 
     22 TEST(ErrorOr, SimpleValue) {
     23   ErrorOr<int> a = t1();
     24   // FIXME: This is probably a bug in gtest. EXPECT_TRUE should expand to
     25   // include the !! to make it friendly to explicit bool operators.
     26   EXPECT_TRUE(!!a);
     27   EXPECT_EQ(1, *a);
     28 
     29   ErrorOr<int> b = a;
     30   EXPECT_EQ(1, *b);
     31 
     32   a = t2();
     33   EXPECT_FALSE(a);
     34   EXPECT_EQ(a.getError(), errc::invalid_argument);
     35 #ifdef EXPECT_DEBUG_DEATH
     36   EXPECT_DEBUG_DEATH(*a, "Cannot get value when an error exists");
     37 #endif
     38 }
     39 
     40 ErrorOr<std::unique_ptr<int> > t3() {
     41   return std::unique_ptr<int>(new int(3));
     42 }
     43 
     44 TEST(ErrorOr, Types) {
     45   int x;
     46   ErrorOr<int&> a(x);
     47   *a = 42;
     48   EXPECT_EQ(42, x);
     49 
     50   // Move only types.
     51   EXPECT_EQ(3, **t3());
     52 }
     53 
     54 struct B {};
     55 struct D : B {};
     56 
     57 TEST(ErrorOr, Covariant) {
     58   ErrorOr<B*> b(ErrorOr<D*>(nullptr));
     59   b = ErrorOr<D*>(nullptr);
     60 
     61   ErrorOr<std::unique_ptr<B> > b1(ErrorOr<std::unique_ptr<D> >(nullptr));
     62   b1 = ErrorOr<std::unique_ptr<D> >(nullptr);
     63 
     64   ErrorOr<std::unique_ptr<int>> b2(ErrorOr<int *>(nullptr));
     65   ErrorOr<int *> b3(nullptr);
     66   ErrorOr<std::unique_ptr<int>> b4(b3);
     67 }
     68 
     69 TEST(ErrorOr, Comparison) {
     70   ErrorOr<int> x(errc::no_such_file_or_directory);
     71   EXPECT_EQ(x, errc::no_such_file_or_directory);
     72 }
     73 
     74 TEST(ErrorOr, ImplicitConversion) {
     75   ErrorOr<std::string> x("string literal");
     76   EXPECT_TRUE(!!x);
     77 }
     78 
     79 TEST(ErrorOr, ImplicitConversionCausesMove) {
     80   struct Source {};
     81   struct Destination {
     82     Destination(const Source&) {}
     83     Destination(Source&&) = delete;
     84   };
     85   Source s;
     86   ErrorOr<Destination> x = s;
     87   EXPECT_TRUE(!!x);
     88 }
     89 
     90 TEST(ErrorOr, ImplicitConversionNoAmbiguity) {
     91   struct CastsToErrorCode {
     92     CastsToErrorCode() = default;
     93     CastsToErrorCode(std::error_code) {}
     94     operator std::error_code() { return errc::invalid_argument; }
     95   } casts_to_error_code;
     96   ErrorOr<CastsToErrorCode> x1(casts_to_error_code);
     97   ErrorOr<CastsToErrorCode> x2 = casts_to_error_code;
     98   ErrorOr<CastsToErrorCode> x3 = {casts_to_error_code};
     99   ErrorOr<CastsToErrorCode> x4{casts_to_error_code};
    100   ErrorOr<CastsToErrorCode> x5(errc::no_such_file_or_directory);
    101   ErrorOr<CastsToErrorCode> x6 = errc::no_such_file_or_directory;
    102   ErrorOr<CastsToErrorCode> x7 = {errc::no_such_file_or_directory};
    103   ErrorOr<CastsToErrorCode> x8{errc::no_such_file_or_directory};
    104   EXPECT_TRUE(!!x1);
    105   EXPECT_TRUE(!!x2);
    106   EXPECT_TRUE(!!x3);
    107   EXPECT_TRUE(!!x4);
    108   EXPECT_FALSE(x5);
    109   EXPECT_FALSE(x6);
    110   EXPECT_FALSE(x7);
    111   EXPECT_FALSE(x8);
    112 }
    113 
    114 // ErrorOr<int*> x(nullptr);
    115 // ErrorOr<std::unique_ptr<int>> y = x; // invalid conversion
    116 static_assert(
    117     !std::is_convertible<const ErrorOr<int *> &,
    118                          ErrorOr<std::unique_ptr<int>>>::value,
    119     "do not invoke explicit ctors in implicit conversion from lvalue");
    120 
    121 // ErrorOr<std::unique_ptr<int>> y = ErrorOr<int*>(nullptr); // invalid
    122 //                                                           // conversion
    123 static_assert(
    124     !std::is_convertible<ErrorOr<int *> &&,
    125                          ErrorOr<std::unique_ptr<int>>>::value,
    126     "do not invoke explicit ctors in implicit conversion from rvalue");
    127 
    128 // ErrorOr<int*> x(nullptr);
    129 // ErrorOr<std::unique_ptr<int>> y;
    130 // y = x; // invalid conversion
    131 static_assert(!std::is_assignable<ErrorOr<std::unique_ptr<int>>,
    132                                   const ErrorOr<int *> &>::value,
    133               "do not invoke explicit ctors in assignment");
    134 
    135 // ErrorOr<std::unique_ptr<int>> x;
    136 // x = ErrorOr<int*>(nullptr); // invalid conversion
    137 static_assert(!std::is_assignable<ErrorOr<std::unique_ptr<int>>,
    138                                   ErrorOr<int *> &&>::value,
    139               "do not invoke explicit ctors in assignment");
    140 } // end anon namespace
    141