Fix "unsafe narrowing" warnings in absl, 3/n.

Addresses failures with the following, in some files:
-Wshorten-64-to-32
-Wimplicit-int-conversion
-Wsign-compare
-Wsign-conversion
-Wtautological-unsigned-zero-compare

(This specific CL focuses on .cc files in dirs n-t, except string.)

Bug: chromium:1292951
PiperOrigin-RevId: 465287204
Change-Id: I0fe98ff78bf3c08d86992019eb626755f8b6803e

9 files changed, 114 insertions, 89 deletions

diff --git a/absl/numeric/int128.cc b/absl/numeric/int128.cc
index 8cdcbf05..e5526c6f 100644
--- a/absl/numeric/int128.cc
+++ b/absl/numeric/int128.cc
@@ -209,15 +209,16 @@ std::ostream& operator<<(std::ostream& os, uint128 v) {
   // Add the requisite padding.
   std::streamsize width = os.width(0);
   if (static_cast<size_t>(width) > rep.size()) {
+    const size_t count = static_cast<size_t>(width) - rep.size();
     std::ios::fmtflags adjustfield = flags & std::ios::adjustfield;
     if (adjustfield == std::ios::left) {
-      rep.append(width - rep.size(), os.fill());
+      rep.append(count, os.fill());
     } else if (adjustfield == std::ios::internal &&
                (flags & std::ios::showbase) &&
                (flags & std::ios::basefield) == std::ios::hex && v != 0) {
-      rep.insert(2, width - rep.size(), os.fill());
+      rep.insert(2, count, os.fill());
     } else {
-      rep.insert(0, width - rep.size(), os.fill());
+      rep.insert(0, count, os.fill());
     }
   }
 
@@ -306,22 +307,23 @@ std::ostream& operator<<(std::ostream& os, int128 v) {
   // Add the requisite padding.
   std::streamsize width = os.width(0);
   if (static_cast<size_t>(width) > rep.size()) {
+    const size_t count = static_cast<size_t>(width) - rep.size();
     switch (flags & std::ios::adjustfield) {
       case std::ios::left:
-        rep.append(width - rep.size(), os.fill());
+        rep.append(count, os.fill());
         break;
       case std::ios::internal:
         if (print_as_decimal && (rep[0] == '+' || rep[0] == '-')) {
-          rep.insert(1, width - rep.size(), os.fill());
+          rep.insert(1, count, os.fill());
         } else if ((flags & std::ios::basefield) == std::ios::hex &&
                    (flags & std::ios::showbase) && v != 0) {
-          rep.insert(2, width - rep.size(), os.fill());
+          rep.insert(2, count, os.fill());
         } else {
-          rep.insert(0, width - rep.size(), os.fill());
+          rep.insert(0, count, os.fill());
         }
         break;
       default:  // std::ios::right
-        rep.insert(0, width - rep.size(), os.fill());
+        rep.insert(0, count, os.fill());
         break;
     }
   }
diff --git a/absl/random/internal/pool_urbg.cc b/absl/random/internal/pool_urbg.cc
index 725100a4..5aefa7d9 100644
--- a/absl/random/internal/pool_urbg.cc
+++ b/absl/random/internal/pool_urbg.cc
@@ -131,7 +131,7 @@ void RandenPoolEntry::Fill(uint8_t* out, size_t bytes) {
 }
 
 // Number of pooled urbg entries.
-static constexpr int kPoolSize = 8;
+static constexpr size_t kPoolSize = 8;
 
 // Shared pool entries.
 static absl::once_flag pool_once;
@@ -147,15 +147,15 @@ ABSL_CACHELINE_ALIGNED static RandenPoolEntry* shared_pools[kPoolSize];
 // on subsequent runs the order within the same program may be significantly
 // different. However, as other thread IDs are not assigned sequentially,
 // this is not expected to matter.
-int GetPoolID() {
+size_t GetPoolID() {
   static_assert(kPoolSize >= 1,
                 "At least one urbg instance is required for PoolURBG");
 
-  ABSL_CONST_INIT static std::atomic<int64_t> sequence{0};
+  ABSL_CONST_INIT static std::atomic<uint64_t> sequence{0};
 
 #ifdef ABSL_HAVE_THREAD_LOCAL
-  static thread_local int my_pool_id = -1;
-  if (ABSL_PREDICT_FALSE(my_pool_id < 0)) {
+  static thread_local size_t my_pool_id = kPoolSize;
+  if (ABSL_PREDICT_FALSE(my_pool_id == kPoolSize)) {
     my_pool_id = (sequence++ % kPoolSize);
   }
   return my_pool_id;
@@ -171,8 +171,8 @@ int GetPoolID() {
 
   // Store the value in the pthread_{get/set}specific. However an uninitialized
   // value is 0, so add +1 to distinguish from the null value.
-  intptr_t my_pool_id =
-      reinterpret_cast<intptr_t>(pthread_getspecific(tid_key));
+  uintptr_t my_pool_id =
+      reinterpret_cast<uintptr_t>(pthread_getspecific(tid_key));
   if (ABSL_PREDICT_FALSE(my_pool_id == 0)) {
     // No allocated ID, allocate the next value, cache it, and return.
     my_pool_id = (sequence++ % kPoolSize) + 1;
@@ -194,7 +194,7 @@ RandenPoolEntry* PoolAlignedAlloc() {
   // Not all the platforms that we build for have std::aligned_alloc, however
   // since we never free these objects, we can over allocate and munge the
   // pointers to the correct alignment.
-  intptr_t x = reinterpret_cast<intptr_t>(
+  uintptr_t x = reinterpret_cast<uintptr_t>(
       new char[sizeof(RandenPoolEntry) + kAlignment]);
   auto y = x % kAlignment;
   void* aligned = reinterpret_cast<void*>(y == 0 ? x : (x + kAlignment - y));
@@ -215,7 +215,7 @@ void InitPoolURBG() {
           absl::MakeSpan(seed_material))) {
     random_internal::ThrowSeedGenException();
   }
-  for (int i = 0; i < kPoolSize; i++) {
+  for (size_t i = 0; i < kPoolSize; i++) {
     shared_pools[i] = PoolAlignedAlloc();
     shared_pools[i]->Init(
         absl::MakeSpan(&seed_material[i * kSeedSize], kSeedSize));
diff --git a/absl/status/status.cc b/absl/status/status.cc
index 88e8eda9..bbf2335d 100644
--- a/absl/status/status.cc
+++ b/absl/status/status.cc
@@ -16,6 +16,7 @@
 #include <errno.h>
 
 #include <cassert>
+#include <utility>
 
 #include "absl/base/internal/raw_logging.h"
 #include "absl/base/internal/strerror.h"
@@ -77,15 +78,17 @@ std::ostream& operator<<(std::ostream& os, StatusCode code) {
 
 namespace status_internal {
 
-static int FindPayloadIndexByUrl(const Payloads* payloads,
-                                 absl::string_view type_url) {
-  if (payloads == nullptr) return -1;
+static absl::optional<size_t> FindPayloadIndexByUrl(
+    const Payloads* payloads,
+    absl::string_view type_url) {
+  if (payloads == nullptr)
+    return absl::nullopt;
 
   for (size_t i = 0; i < payloads->size(); ++i) {
     if ((*payloads)[i].type_url == type_url) return i;
   }
 
-  return -1;
+  return absl::nullopt;
 }
 
 // Convert canonical code to a value known to this binary.
@@ -119,8 +122,10 @@ absl::StatusCode MapToLocalCode(int value) {
 absl::optional<absl::Cord> Status::GetPayload(
     absl::string_view type_url) const {
   const auto* payloads = GetPayloads();
-  int index = status_internal::FindPayloadIndexByUrl(payloads, type_url);
-  if (index != -1) return (*payloads)[index].payload;
+  absl::optional<size_t> index =
+      status_internal::FindPayloadIndexByUrl(payloads, type_url);
+  if (index.has_value())
+    return (*payloads)[index.value()].payload;
 
   return absl::nullopt;
 }
@@ -135,10 +140,10 @@ void Status::SetPayload(absl::string_view type_url, absl::Cord payload) {
     rep->payloads = absl::make_unique<status_internal::Payloads>();
   }
 
-  int index =
+  absl::optional<size_t> index =
       status_internal::FindPayloadIndexByUrl(rep->payloads.get(), type_url);
-  if (index != -1) {
-    (*rep->payloads)[index].payload = std::move(payload);
+  if (index.has_value()) {
+    (*rep->payloads)[index.value()].payload = std::move(payload);
     return;
   }
 
@@ -146,10 +151,11 @@ void Status::SetPayload(absl::string_view type_url, absl::Cord payload) {
 }
 
 bool Status::ErasePayload(absl::string_view type_url) {
-  int index = status_internal::FindPayloadIndexByUrl(GetPayloads(), type_url);
-  if (index != -1) {
+  absl::optional<size_t> index =
+      status_internal::FindPayloadIndexByUrl(GetPayloads(), type_url);
+  if (index.has_value()) {
     PrepareToModify();
-    GetPayloads()->erase(GetPayloads()->begin() + index);
+    GetPayloads()->erase(GetPayloads()->begin() + index.value());
     if (GetPayloads()->empty() && message().empty()) {
       // Special case: If this can be represented inlined, it MUST be
       // inlined (EqualsSlow depends on this behavior).
diff --git a/absl/synchronization/internal/graphcycles.cc b/absl/synchronization/internal/graphcycles.cc
index 27fec216..feec4581 100644
--- a/absl/synchronization/internal/graphcycles.cc
+++ b/absl/synchronization/internal/graphcycles.cc
@@ -181,9 +181,9 @@ class NodeSet {
     return true;
   }
 
-  void erase(uint32_t v) {
+  void erase(int32_t v) {
     uint32_t i = FindIndex(v);
-    if (static_cast<uint32_t>(table_[i]) == v) {
+    if (table_[i] == v) {
       table_[i] = kDel;
     }
   }
@@ -195,7 +195,7 @@ class NodeSet {
   for (int32_t elem, _cursor = 0; (eset).Next(&_cursor, &elem); )
   bool Next(int32_t* cursor, int32_t* elem) {
     while (static_cast<uint32_t>(*cursor) < table_.size()) {
-      int32_t v = table_[*cursor];
+      int32_t v = table_[static_cast<uint32_t>(*cursor)];
       (*cursor)++;
       if (v >= 0) {
         *elem = v;
@@ -210,24 +210,26 @@ class NodeSet {
   Vec<int32_t> table_;
   uint32_t occupied_;     // Count of non-empty slots (includes deleted slots)
 
-  static uint32_t Hash(uint32_t a) { return a * 41; }
+  static uint32_t Hash(int32_t a) { return static_cast<uint32_t>(a * 41); }
 
   // Return index for storing v.  May return an empty index or deleted index
-  int FindIndex(int32_t v) const {
+  uint32_t FindIndex(int32_t v) const {
     // Search starting at hash index.
     const uint32_t mask = table_.size() - 1;
     uint32_t i = Hash(v) & mask;
-    int deleted_index = -1;  // If >= 0, index of first deleted element we see
+    uint32_t deleted_index = 0;  // index of first deleted element we see
+    bool seen_deleted_element = false;
     while (true) {
       int32_t e = table_[i];
       if (v == e) {
         return i;
       } else if (e == kEmpty) {
         // Return any previously encountered deleted slot.
-        return (deleted_index >= 0) ? deleted_index : i;
-      } else if (e == kDel && deleted_index < 0) {
+        return seen_deleted_element ? deleted_index : i;
+      } else if (e == kDel && !seen_deleted_element) {
         // Keep searching since v might be present later.
         deleted_index = i;
+        seen_deleted_element = true;
       }
       i = (i + 1) & mask;  // Linear probing; quadratic is slightly slower.
     }
@@ -268,7 +270,7 @@ inline GraphId MakeId(int32_t index, uint32_t version) {
 }
 
 inline int32_t NodeIndex(GraphId id) {
-  return static_cast<uint32_t>(id.handle & 0xfffffffful);
+  return static_cast<int32_t>(id.handle);
 }
 
 inline uint32_t NodeVersion(GraphId id) {
@@ -298,7 +300,7 @@ class PointerMap {
   int32_t Find(void* ptr) {
     auto masked = base_internal::HidePtr(ptr);
     for (int32_t i = table_[Hash(ptr)]; i != -1;) {
-      Node* n = (*nodes_)[i];
+      Node* n = (*nodes_)[static_cast<uint32_t>(i)];
       if (n->masked_ptr == masked) return i;
       i = n->next_hash;
     }
@@ -307,7 +309,7 @@ class PointerMap {
 
   void Add(void* ptr, int32_t i) {
     int32_t* head = &table_[Hash(ptr)];
-    (*nodes_)[i]->next_hash = *head;
+    (*nodes_)[static_cast<uint32_t>(i)]->next_hash = *head;
     *head = i;
   }
 
@@ -317,7 +319,7 @@ class PointerMap {
     auto masked = base_internal::HidePtr(ptr);
     for (int32_t* slot = &table_[Hash(ptr)]; *slot != -1; ) {
       int32_t index = *slot;
-      Node* n = (*nodes_)[index];
+      Node* n = (*nodes_)[static_cast<uint32_t>(index)];
       if (n->masked_ptr == masked) {
         *slot = n->next_hash;  // Remove n from linked list
         n->next_hash = -1;
@@ -358,7 +360,7 @@ struct GraphCycles::Rep {
 };
 
 static Node* FindNode(GraphCycles::Rep* rep, GraphId id) {
-  Node* n = rep->nodes_[NodeIndex(id)];
+  Node* n = rep->nodes_[static_cast<uint32_t>(NodeIndex(id))];
   return (n->version == NodeVersion(id)) ? n : nullptr;
 }
 
@@ -393,7 +395,7 @@ bool GraphCycles::CheckInvariants() const {
       ABSL_RAW_LOG(FATAL, "Duplicate occurrence of rank %d", nx->rank);
     }
     HASH_FOR_EACH(y, nx->out) {
-      Node* ny = r->nodes_[y];
+      Node* ny = r->nodes_[static_cast<uint32_t>(y)];
       if (nx->rank >= ny->rank) {
         ABSL_RAW_LOG(FATAL, "Edge %u->%d has bad rank assignment %d->%d", x, y,
                      nx->rank, ny->rank);
@@ -406,14 +408,14 @@ bool GraphCycles::CheckInvariants() const {
 GraphId GraphCycles::GetId(void* ptr) {
   int32_t i = rep_->ptrmap_.Find(ptr);
   if (i != -1) {
-    return MakeId(i, rep_->nodes_[i]->version);
+    return MakeId(i, rep_->nodes_[static_cast<uint32_t>(i)]->version);
   } else if (rep_->free_nodes_.empty()) {
     Node* n =
         new (base_internal::LowLevelAlloc::AllocWithArena(sizeof(Node), arena))
             Node;
     n->version = 1;  // Avoid 0 since it is used by InvalidGraphId()
     n->visited = false;
-    n->rank = rep_->nodes_.size();
+    n->rank = static_cast<int32_t>(rep_->nodes_.size());
     n->masked_ptr = base_internal::HidePtr(ptr);
     n->nstack = 0;
     n->priority = 0;
@@ -425,7 +427,7 @@ GraphId GraphCycles::GetId(void* ptr) {
     // a permutation of [0,rep_->nodes_.size()-1].
     int32_t r = rep_->free_nodes_.back();
     rep_->free_nodes_.pop_back();
-    Node* n = rep_->nodes_[r];
+    Node* n = rep_->nodes_[static_cast<uint32_t>(r)];
     n->masked_ptr = base_internal::HidePtr(ptr);
     n->nstack = 0;
     n->priority = 0;
@@ -439,12 +441,12 @@ void GraphCycles::RemoveNode(void* ptr) {
   if (i == -1) {
     return;
   }
-  Node* x = rep_->nodes_[i];
+  Node* x = rep_->nodes_[static_cast<uint32_t>(i)];
   HASH_FOR_EACH(y, x->out) {
-    rep_->nodes_[y]->in.erase(i);
+    rep_->nodes_[static_cast<uint32_t>(y)]->in.erase(i);
   }
   HASH_FOR_EACH(y, x->in) {
-    rep_->nodes_[y]->out.erase(i);
+    rep_->nodes_[static_cast<uint32_t>(y)]->out.erase(i);
   }
   x->in.clear();
   x->out.clear();
@@ -520,7 +522,7 @@ bool GraphCycles::InsertEdge(GraphId idx, GraphId idy) {
     // Since we do not call Reorder() on this path, clear any visited
     // markers left by ForwardDFS.
     for (const auto& d : r->deltaf_) {
-      r->nodes_[d]->visited = false;
+      r->nodes_[static_cast<uint32_t>(d)]->visited = false;
     }
     return false;
   }
@@ -538,14 +540,14 @@ static bool ForwardDFS(GraphCycles::Rep* r, int32_t n, int32_t upper_bound) {
   while (!r->stack_.empty()) {
     n = r->stack_.back();
     r->stack_.pop_back();
-    Node* nn = r->nodes_[n];
+    Node* nn = r->nodes_[static_cast<uint32_t>(n)];
     if (nn->visited) continue;
 
     nn->visited = true;
     r->deltaf_.push_back(n);
 
     HASH_FOR_EACH(w, nn->out) {
-      Node* nw = r->nodes_[w];
+      Node* nw = r->nodes_[static_cast<uint32_t>(w)];
       if (nw->rank == upper_bound) {
         return false;  // Cycle
       }
@@ -564,14 +566,14 @@ static void BackwardDFS(GraphCycles::Rep* r, int32_t n, int32_t lower_bound) {
   while (!r->stack_.empty()) {
     n = r->stack_.back();
     r->stack_.pop_back();
-    Node* nn = r->nodes_[n];
+    Node* nn = r->nodes_[static_cast<uint32_t>(n)];
     if (nn->visited) continue;
 
     nn->visited = true;
     r->deltab_.push_back(n);
 
     HASH_FOR_EACH(w, nn->in) {
-      Node* nw = r->nodes_[w];
+      Node* nw = r->nodes_[static_cast<uint32_t>(w)];
       if (!nw->visited && lower_bound < nw->rank) {
         r->stack_.push_back(w);
       }
@@ -596,7 +598,7 @@ static void Reorder(GraphCycles::Rep* r) {
 
   // Assign the ranks in order to the collected list.
   for (uint32_t i = 0; i < r->list_.size(); i++) {
-    r->nodes_[r->list_[i]]->rank = r->merged_[i];
+    r->nodes_[static_cast<uint32_t>(r->list_[i])]->rank = r->merged_[i];
   }
 }
 
@@ -604,7 +606,8 @@ static void Sort(const Vec<Node*>& nodes, Vec<int32_t>* delta) {
   struct ByRank {
     const Vec<Node*>* nodes;
     bool operator()(int32_t a, int32_t b) const {
-      return (*nodes)[a]->rank < (*nodes)[b]->rank;
+      return (*nodes)[static_cast<uint32_t>(a)]->rank <
+             (*nodes)[static_cast<uint32_t>(b)]->rank;
     }
   };
   ByRank cmp;
@@ -616,8 +619,10 @@ static void MoveToList(
     GraphCycles::Rep* r, Vec<int32_t>* src, Vec<int32_t>* dst) {
   for (auto& v : *src) {
     int32_t w = v;
-    v = r->nodes_[w]->rank;         // Replace v entry with its rank
-    r->nodes_[w]->visited = false;  // Prepare for future DFS calls
+    // Replace v entry with its rank
+    v = r->nodes_[static_cast<uint32_t>(w)]->rank;
+    // Prepare for future DFS calls
+    r->nodes_[static_cast<uint32_t>(w)]->visited = false;
     dst->push_back(w);
   }
 }
@@ -647,7 +652,8 @@ int GraphCycles::FindPath(GraphId idx, GraphId idy, int max_path_len,
     }
 
     if (path_len < max_path_len) {
-      path[path_len] = MakeId(n, rep_->nodes_[n]->version);
+      path[path_len] =
+          MakeId(n, rep_->nodes_[static_cast<uint32_t>(n)]->version);
     }
     path_len++;
     r->stack_.push_back(-1);  // Will remove tentative path entry
@@ -656,7 +662,7 @@ int GraphCycles::FindPath(GraphId idx, GraphId idy, int max_path_len,
       return path_len;
     }
 
-    HASH_FOR_EACH(w, r->nodes_[n]->out) {
+    HASH_FOR_EACH(w, r->nodes_[static_cast<uint32_t>(n)]->out) {
       if (seen.insert(w)) {
         r->stack_.push_back(w);
       }
diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc
index 64177360..2662c071 100644
--- a/absl/synchronization/mutex.cc
+++ b/absl/synchronization/mutex.cc
@@ -326,7 +326,7 @@ static struct SynchEvent {     // this is a trivial hash table for the events
 static SynchEvent *EnsureSynchEvent(std::atomic<intptr_t> *addr,
                                     const char *name, intptr_t bits,
                                     intptr_t lockbit) {
-  uint32_t h = reinterpret_cast<intptr_t>(addr) % kNSynchEvent;
+  uint32_t h = reinterpret_cast<uintptr_t>(addr) % kNSynchEvent;
   SynchEvent *e;
   // first look for existing SynchEvent struct..
   synch_event_mu.Lock();
@@ -379,7 +379,7 @@ static void UnrefSynchEvent(SynchEvent *e) {
 // is clear before doing so).
 static void ForgetSynchEvent(std::atomic<intptr_t> *addr, intptr_t bits,
                              intptr_t lockbit) {
-  uint32_t h = reinterpret_cast<intptr_t>(addr) % kNSynchEvent;
+  uint32_t h = reinterpret_cast<uintptr_t>(addr) % kNSynchEvent;
   SynchEvent **pe;
   SynchEvent *e;
   synch_event_mu.Lock();
@@ -403,7 +403,7 @@ static void ForgetSynchEvent(std::atomic<intptr_t> *addr, intptr_t bits,
 // "addr", if any.  The pointer returned is valid until the UnrefSynchEvent() is
 // called.
 static SynchEvent *GetSynchEvent(const void *addr) {
-  uint32_t h = reinterpret_cast<intptr_t>(addr) % kNSynchEvent;
+  uint32_t h = reinterpret_cast<uintptr_t>(addr) % kNSynchEvent;
   SynchEvent *e;
   synch_event_mu.Lock();
   for (e = synch_event[h];
@@ -431,8 +431,10 @@ static void PostSynchEvent(void *obj, int ev) {
     char buffer[ABSL_ARRAYSIZE(pcs) * 24];
     int pos = snprintf(buffer, sizeof (buffer), " @");
     for (int i = 0; i != n; i++) {
-      int b = snprintf(&buffer[pos], sizeof(buffer) - pos, " %p", pcs[i]);
-      if (b < 0 || static_cast<size_t>(b) >= sizeof(buffer) - pos) {
+      int b = snprintf(&buffer[pos], sizeof(buffer) - static_cast<size_t>(pos),
+                       " %p", pcs[i]);
+      if (b < 0 ||
+          static_cast<size_t>(b) >= sizeof(buffer) - static_cast<size_t>(pos)) {
         break;
       }
       pos += b;
@@ -1278,15 +1280,17 @@ static char *StackString(void **pcs, int n, char *buf, int maxlen,
   char sym[kSymLen];
   int len = 0;
   for (int i = 0; i != n; i++) {
+    if (len >= maxlen)
+      return buf;
+    size_t count = static_cast<size_t>(maxlen - len);
     if (symbolize) {
       if (!symbolizer(pcs[i], sym, kSymLen)) {
         sym[0] = '\0';
       }
-      snprintf(buf + len, maxlen - len, "%s\t@ %p %s\n",
-               (i == 0 ? "\n" : ""),
-               pcs[i], sym);
+      snprintf(buf + len, count, "%s\t@ %p %s\n", (i == 0 ? "\n" : ""), pcs[i],
+               sym);
     } else {
-      snprintf(buf + len, maxlen - len, " %p", pcs[i]);
+      snprintf(buf + len, count, " %p", pcs[i]);
     }
     len += strlen(&buf[len]);
   }
@@ -1371,12 +1375,12 @@ static GraphId DeadlockCheck(Mutex *mu) {
       bool symbolize = number_of_reported_deadlocks <= 2;
       ABSL_RAW_LOG(ERROR, "Potential Mutex deadlock: %s",
                    CurrentStackString(b->buf, sizeof (b->buf), symbolize));
-      int len = 0;
+      size_t len = 0;
       for (int j = 0; j != all_locks->n; j++) {
         void* pr = deadlock_graph->Ptr(all_locks->locks[j].id);
         if (pr != nullptr) {
           snprintf(b->buf + len, sizeof (b->buf) - len, " %p", pr);
-          len += static_cast<int>(strlen(&b->buf[len]));
+          len += strlen(&b->buf[len]);
         }
       }
       ABSL_RAW_LOG(ERROR,
@@ -1909,7 +1913,7 @@ static void CheckForMutexCorruption(intptr_t v, const char* label) {
   // Test for either of two situations that should not occur in v:
   //   kMuWriter and kMuReader
   //   kMuWrWait and !kMuWait
-  const uintptr_t w = v ^ kMuWait;
+  const uintptr_t w = static_cast<uintptr_t>(v ^ kMuWait);
   // By flipping that bit, we can now test for:
   //   kMuWriter and kMuReader in w
   //   kMuWrWait and kMuWait in w
diff --git a/absl/time/clock.cc b/absl/time/clock.cc
index 7b204c4e..dba31611 100644
--- a/absl/time/clock.cc
+++ b/absl/time/clock.cc
@@ -217,9 +217,11 @@ static int64_t GetCurrentTimeNanosFromKernel(uint64_t last_cycleclock,
   uint64_t elapsed_cycles;
   int loops = 0;
   do {
-    before_cycles = GET_CURRENT_TIME_NANOS_CYCLECLOCK_NOW();
+    before_cycles =
+        static_cast<uint64_t>(GET_CURRENT_TIME_NANOS_CYCLECLOCK_NOW());
     current_time_nanos_from_system = GET_CURRENT_TIME_NANOS_FROM_SYSTEM();
-    after_cycles = GET_CURRENT_TIME_NANOS_CYCLECLOCK_NOW();
+    after_cycles =
+        static_cast<uint64_t>(GET_CURRENT_TIME_NANOS_CYCLECLOCK_NOW());
     // elapsed_cycles is unsigned, so is large on overflow
     elapsed_cycles = after_cycles - before_cycles;
     if (elapsed_cycles >= local_approx_syscall_time_in_cycles &&
@@ -316,7 +318,8 @@ int64_t GetCurrentTimeNanos() {
   // contribute to register pressure - reading it early before initializing
   // the other pieces of the calculation minimizes spill/restore instructions,
   // minimizing icache cost.
-  uint64_t now_cycles = GET_CURRENT_TIME_NANOS_CYCLECLOCK_NOW();
+  uint64_t now_cycles =
+      static_cast<uint64_t>(GET_CURRENT_TIME_NANOS_CYCLECLOCK_NOW());
 
   // Acquire pairs with the barrier in SeqRelease - if this load sees that
   // store, the shared-data reads necessarily see that SeqRelease's updates
@@ -356,7 +359,8 @@ int64_t GetCurrentTimeNanos() {
   uint64_t delta_cycles;
   if (seq_read0 == seq_read1 && (seq_read0 & 1) == 0 &&
       (delta_cycles = now_cycles - base_cycles) < min_cycles_per_sample) {
-    return base_ns + ((delta_cycles * nsscaled_per_cycle) >> kScale);
+    return static_cast<int64_t>(
+        base_ns + ((delta_cycles * nsscaled_per_cycle) >> kScale));
   }
   return GetCurrentTimeNanosSlowPath();
 }
@@ -404,8 +408,8 @@ static int64_t GetCurrentTimeNanosSlowPath()
   // Sample the kernel time base.  This is the definition of
   // "now" if we take the slow path.
   uint64_t now_cycles;
-  uint64_t now_ns =
-      GetCurrentTimeNanosFromKernel(time_state.last_now_cycles, &now_cycles);
+  uint64_t now_ns = static_cast<uint64_t>(
+      GetCurrentTimeNanosFromKernel(time_state.last_now_cycles, &now_cycles));
   time_state.last_now_cycles = now_cycles;
 
   uint64_t estimated_base_ns;
@@ -432,7 +436,7 @@ static int64_t GetCurrentTimeNanosSlowPath()
 
   time_state.lock.Unlock();
 
-  return estimated_base_ns;
+  return static_cast<int64_t>(estimated_base_ns);
 }
 
 // Main part of the algorithm.  Locks out readers, updates the approximation
@@ -489,7 +493,8 @@ static uint64_t UpdateLastSample(uint64_t now_cycles, uint64_t now_ns,
     uint64_t assumed_next_sample_delta_cycles =
         SafeDivideAndScale(kMinNSBetweenSamples, measured_nsscaled_per_cycle);
 
-    int64_t diff_ns = now_ns - estimated_base_ns;  // estimate low by this much
+    // Estimate low by this much.
+    int64_t diff_ns = static_cast<int64_t>(now_ns - estimated_base_ns);
 
     // We want to set nsscaled_per_cycle so that our estimate of the ns time
     // at the assumed cycle time is the assumed ns time.
@@ -500,7 +505,8 @@ static uint64_t UpdateLastSample(uint64_t now_cycles, uint64_t now_ns,
     // of our current error, by solving:
     //  kMinNSBetweenSamples + diff_ns - (diff_ns / 16) ==
     //  (assumed_next_sample_delta_cycles * nsscaled_per_cycle) >> kScale
-    ns = kMinNSBetweenSamples + diff_ns - (diff_ns / 16);
+    ns = static_cast<uint64_t>(static_cast<int64_t>(kMinNSBetweenSamples) +
+                               diff_ns - (diff_ns / 16));
     uint64_t new_nsscaled_per_cycle =
         SafeDivideAndScale(ns, assumed_next_sample_delta_cycles);
     if (new_nsscaled_per_cycle != 0 &&
@@ -558,7 +564,7 @@ constexpr absl::Duration MaxSleep() {
 // REQUIRES: to_sleep <= MaxSleep().
 void SleepOnce(absl::Duration to_sleep) {
 #ifdef _WIN32
-  Sleep(to_sleep / absl::Milliseconds(1));
+  Sleep(static_cast<DWORD>(to_sleep / absl::Milliseconds(1)));
 #else
   struct timespec sleep_time = absl::ToTimespec(to_sleep);
   while (nanosleep(&sleep_time, &sleep_time) != 0 && errno == EINTR) {
diff --git a/absl/time/duration.cc b/absl/time/duration.cc
index 2bba62da..1f4cf382 100644
--- a/absl/time/duration.cc
+++ b/absl/time/duration.cc
@@ -645,7 +645,7 @@ timeval ToTimeval(Duration d) {
       ts.tv_nsec -= 1000 * 1000 * 1000;
     }
   }
-  tv.tv_sec = ts.tv_sec;
+  tv.tv_sec = static_cast<decltype(tv.tv_sec)>(ts.tv_sec);
   if (tv.tv_sec != ts.tv_sec) {  // narrowing
     if (ts.tv_sec < 0) {
       tv.tv_sec = std::numeric_limits<decltype(tv.tv_sec)>::min();
@@ -728,7 +728,7 @@ void AppendNumberUnit(std::string* out, int64_t n, DisplayUnit unit) {
   char* const ep = buf + sizeof(buf);
   char* bp = Format64(ep, 0, n);
   if (*bp != '0' || bp + 1 != ep) {
-    out->append(bp, ep - bp);
+    out->append(bp, static_cast<size_t>(ep - bp));
     out->append(unit.abbr.data(), unit.abbr.size());
   }
 }
@@ -745,12 +745,12 @@ void AppendNumberUnit(std::string* out, double n, DisplayUnit unit) {
   int64_t int_part = d;
   if (int_part != 0 || frac_part != 0) {
     char* bp = Format64(ep, 0, int_part);  // always < 1000
-    out->append(bp, ep - bp);
+    out->append(bp, static_cast<size_t>(ep - bp));
     if (frac_part != 0) {
       out->push_back('.');
       bp = Format64(ep, prec, frac_part);
       while (ep[-1] == '0') --ep;
-      out->append(bp, ep - bp);
+      out->append(bp, static_cast<size_t>(ep - bp));
     }
     out->append(unit.abbr.data(), unit.abbr.size());
   }
@@ -841,7 +841,7 @@ bool ConsumeDurationNumber(const char** dpp, const char* ep, int64_t* int_part,
 // in "*unit".  The given string pointer is modified to point to the first
 // unconsumed char.
 bool ConsumeDurationUnit(const char** start, const char* end, Duration* unit) {
-  size_t size = end - *start;
+  size_t size = static_cast<size_t>(end - *start);
   switch (size) {
     case 0:
       return false;
diff --git a/absl/time/format.cc b/absl/time/format.cc
index 4005fb70..15a26b14 100644
--- a/absl/time/format.cc
+++ b/absl/time/format.cc
@@ -64,7 +64,8 @@ cctz_parts Split(absl::Time t) {
 // details about rep_hi and rep_lo.
 absl::Time Join(const cctz_parts& parts) {
   const int64_t rep_hi = (parts.sec - unix_epoch()).count();
-  const uint32_t rep_lo = parts.fem.count() / (1000 * 1000 / 4);
+  const uint32_t rep_lo =
+      static_cast<uint32_t>(parts.fem.count() / (1000 * 1000 / 4));
   const auto d = time_internal::MakeDuration(rep_hi, rep_lo);
   return time_internal::FromUnixDuration(d);
 }
diff --git a/absl/time/time.cc b/absl/time/time.cc
index 1ec2026e..718b88c8 100644
--- a/absl/time/time.cc
+++ b/absl/time/time.cc
@@ -316,7 +316,7 @@ timespec ToTimespec(Time t) {
 timeval ToTimeval(Time t) {
   timeval tv;
   timespec ts = absl::ToTimespec(t);
-  tv.tv_sec = ts.tv_sec;
+  tv.tv_sec = static_cast<decltype(tv.tv_sec)>(ts.tv_sec);
   if (tv.tv_sec != ts.tv_sec) {  // narrowing
     if (ts.tv_sec < 0) {
       tv.tv_sec = std::numeric_limits<decltype(tv.tv_sec)>::min();