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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <array>
#include <cstdint>
#include <vector>
#include "base/containers/span.h"
#include "base/numerics/safe_conversions.h"
int UnsafeIndex();
unsigned int UnsafeUnsignedIndex();
// Expected rewrite:
// void UnsafelyModifyIntSlice(base::span<int> slice) {
void UnsafelyModifyIntSlice(base::span<int> slice) {
slice[UnsafeIndex()] = 0;
}
void SubspanIntoCStyleArrayIsUnsigned() {
// Expected rewrite:
// static auto ints = std::to_array<int>({0, 1, 2});
static auto ints = std::to_array<int>({0, 1, 2});
// Unsigned integer literal -> propagate it as written.
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(1u));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(1u));
// Expression that evaluates unsigned -> propagate it as written.
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(UnsafeUnsignedIndex()));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(UnsafeUnsignedIndex()));
// Signed integer literal -> postfix `u`.
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u));
// 1. Different signedness
// 2. `3` is promoted to unsigned
// 3. We can see that the expression is unsigned
// 4. Propagate it as written.
//
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u - 1));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u - 1));
// Indexing expression is not integer literal and is signed
// -> wrap the expression in `checked_cast`.
//
// Incidentally, this triggers arrayification of `ints`.
//
// Expected rewrite:
// UnsafelyModifyIntSlice(
// base::span<int>(ints).subspan(base::checked_cast<size_t>(UnsafeIndex())));
UnsafelyModifyIntSlice(
base::span<int>(ints).subspan(base::checked_cast<size_t>(UnsafeIndex())));
// Compound version of the preceding
// -> wrap the expression in `checked_cast`.
//
// Expected rewrite:
// UnsafelyModifyIntSlice(
// base::span<int>(ints).subspan(base::checked_cast<size_t>(UnsafeIndex()
// + 1)));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(
base::checked_cast<size_t>(UnsafeIndex() + 1)));
}
// The same test cases as `SubspanIntoCStyleArrayIsUnsigned`.
void SubspanIntoContainerishArrayIsUnsigned() {
static std::vector<int> ints = {0, 1, 2};
// Unsigned integer literal -> propagate it as written.
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(1u));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(1u));
// Expression that evaluates unsigned -> propagate it as written.
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(UnsafeUnsignedIndex()));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(UnsafeUnsignedIndex()));
// Signed integer literal -> postfix `u`.
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u));
// 1. Different signedness
// 2. `3` is promoted to unsigned
// 3. We can see that the expression is unsigned
// 4. Propagate it as written.
//
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u - 1));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(2u - 1));
// Indexing expression is not integer literal and is signed
// -> wrap the expression in `checked_cast`.
//
// Expected rewrite:
// UnsafelyModifyIntSlice(
// base::span<int>(ints).subspan(base::checked_cast<size_t>(UnsafeIndex())));
UnsafelyModifyIntSlice(
base::span<int>(ints).subspan(base::checked_cast<size_t>(UnsafeIndex())));
// Compound version of the preceding
// -> wrap the expression in `checked_cast`.
//
// Expected rewrite:
// UnsafelyModifyIntSlice(base::span<int>(ints).subspan(
// base::checked_cast<size_t>(UnsafeIndex() + 1)));
UnsafelyModifyIntSlice(base::span<int>(ints).subspan(
base::checked_cast<size_t>(UnsafeIndex() + 1)));
}
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