Fix "unsafe narrowing" warnings in absl, 10/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 tests.)

Bug: chromium:1292951
PiperOrigin-RevId: 473055916
Change-Id: I40cdd6c87ba9d0a5fb2db5746cff04f14ee829c2

9 files changed, 472 insertions, 465 deletions

diff --git a/absl/algorithm/container_test.cc b/absl/algorithm/container_test.cc
index 605afc80..0fbc7773 100644
--- a/absl/algorithm/container_test.cc
+++ b/absl/algorithm/container_test.cc
@@ -67,13 +67,16 @@ bool Equals(int v1, int v2) { return v1 == v2; }
 bool IsOdd(int x) { return x % 2 != 0; }
 
 TEST_F(NonMutatingTest, Distance) {
-  EXPECT_EQ(container_.size(), absl::c_distance(container_));
-  EXPECT_EQ(sequence_.size(), absl::c_distance(sequence_));
-  EXPECT_EQ(vector_.size(), absl::c_distance(vector_));
-  EXPECT_EQ(ABSL_ARRAYSIZE(array_), absl::c_distance(array_));
+  EXPECT_EQ(container_.size(),
+            static_cast<size_t>(absl::c_distance(container_)));
+  EXPECT_EQ(sequence_.size(), static_cast<size_t>(absl::c_distance(sequence_)));
+  EXPECT_EQ(vector_.size(), static_cast<size_t>(absl::c_distance(vector_)));
+  EXPECT_EQ(ABSL_ARRAYSIZE(array_),
+            static_cast<size_t>(absl::c_distance(array_)));
 
   // Works with a temporary argument.
-  EXPECT_EQ(vector_.size(), absl::c_distance(std::vector<int>(vector_)));
+  EXPECT_EQ(vector_.size(),
+            static_cast<size_t>(absl::c_distance(std::vector<int>(vector_))));
 }
 
 TEST_F(NonMutatingTest, Distance_OverloadedBeginEnd) {
diff --git a/absl/base/spinlock_test_common.cc b/absl/base/spinlock_test_common.cc
index 7b6e4b35..52ecf580 100644
--- a/absl/base/spinlock_test_common.cc
+++ b/absl/base/spinlock_test_common.cc
@@ -34,7 +34,7 @@
 #include "absl/synchronization/blocking_counter.h"
 #include "absl/synchronization/notification.h"
 
-constexpr int32_t kNumThreads = 10;
+constexpr uint32_t kNumThreads = 10;
 constexpr int32_t kIters = 1000;
 
 namespace absl {
@@ -55,7 +55,7 @@ struct SpinLockTest {
 
 namespace {
 
-static constexpr int kArrayLength = 10;
+static constexpr size_t kArrayLength = 10;
 static uint32_t values[kArrayLength];
 
 ABSL_CONST_INIT static SpinLock static_cooperative_spinlock(
@@ -79,11 +79,11 @@ static uint32_t Hash32(uint32_t a, uint32_t c) {
   return c;
 }
 
-static void TestFunction(int thread_salt, SpinLock* spinlock) {
+static void TestFunction(uint32_t thread_salt, SpinLock* spinlock) {
   for (int i = 0; i < kIters; i++) {
     SpinLockHolder h(spinlock);
-    for (int j = 0; j < kArrayLength; j++) {
-      const int index = (j + thread_salt) % kArrayLength;
+    for (size_t j = 0; j < kArrayLength; j++) {
+      const size_t index = (j + thread_salt) % kArrayLength;
       values[index] = Hash32(values[index], thread_salt);
       std::this_thread::yield();
     }
@@ -93,7 +93,7 @@ static void TestFunction(int thread_salt, SpinLock* spinlock) {
 static void ThreadedTest(SpinLock* spinlock) {
   std::vector<std::thread> threads;
   threads.reserve(kNumThreads);
-  for (int i = 0; i < kNumThreads; ++i) {
+  for (uint32_t i = 0; i < kNumThreads; ++i) {
     threads.push_back(std::thread(TestFunction, i, spinlock));
   }
   for (auto& thread : threads) {
@@ -101,7 +101,7 @@ static void ThreadedTest(SpinLock* spinlock) {
   }
 
   SpinLockHolder h(spinlock);
-  for (int i = 1; i < kArrayLength; i++) {
+  for (size_t i = 1; i < kArrayLength; i++) {
     EXPECT_EQ(values[0], values[i]);
   }
 }
@@ -153,7 +153,7 @@ TEST(SpinLock, WaitCyclesEncoding) {
     int64_t cycles = cycle_distribution(generator);
     int64_t end_time = start_time + cycles;
     uint32_t lock_value = SpinLockTest::EncodeWaitCycles(start_time, end_time);
-    EXPECT_EQ(0, lock_value & kLockwordReservedMask);
+    EXPECT_EQ(0u, lock_value & kLockwordReservedMask);
     int64_t decoded = SpinLockTest::DecodeWaitCycles(lock_value);
     EXPECT_EQ(0, decoded & kProfileTimestampMask);
     EXPECT_EQ(cycles & ~kProfileTimestampMask, decoded);
diff --git a/absl/container/inlined_vector_test.cc b/absl/container/inlined_vector_test.cc
index 0e528113..b872eb45 100644
--- a/absl/container/inlined_vector_test.cc
+++ b/absl/container/inlined_vector_test.cc
@@ -126,20 +126,20 @@ using DynamicVec = absl::InlinedVector<Dynamic, 8>;
 
 // Append 0..len-1 to *v
 template <typename Container>
-static void Fill(Container* v, int len, int offset = 0) {
-  for (int i = 0; i < len; i++) {
-    v->push_back(i + offset);
+static void Fill(Container* v, size_t len, int offset = 0) {
+  for (size_t i = 0; i < len; i++) {
+    v->push_back(static_cast<int>(i) + offset);
   }
 }
 
-static IntVec Fill(int len, int offset = 0) {
+static IntVec Fill(size_t len, int offset = 0) {
   IntVec v;
   Fill(&v, len, offset);
   return v;
 }
 
 TEST(IntVec, SimpleOps) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     IntVec v;
     const IntVec& cv = v;  // const alias
 
@@ -147,42 +147,42 @@ TEST(IntVec, SimpleOps) {
     EXPECT_EQ(len, v.size());
     EXPECT_LE(len, v.capacity());
 
-    for (int i = 0; i < len; i++) {
-      EXPECT_EQ(i, v[i]);
-      EXPECT_EQ(i, v.at(i));
+    for (size_t i = 0; i < len; i++) {
+      EXPECT_EQ(static_cast<int>(i), v[i]);
+      EXPECT_EQ(static_cast<int>(i), v.at(i));
     }
     EXPECT_EQ(v.begin(), v.data());
     EXPECT_EQ(cv.begin(), cv.data());
 
-    int counter = 0;
+    size_t counter = 0;
     for (IntVec::iterator iter = v.begin(); iter != v.end(); ++iter) {
-      EXPECT_EQ(counter, *iter);
+      EXPECT_EQ(static_cast<int>(counter), *iter);
       counter++;
     }
     EXPECT_EQ(counter, len);
 
     counter = 0;
     for (IntVec::const_iterator iter = v.begin(); iter != v.end(); ++iter) {
-      EXPECT_EQ(counter, *iter);
+      EXPECT_EQ(static_cast<int>(counter), *iter);
       counter++;
     }
     EXPECT_EQ(counter, len);
 
     counter = 0;
     for (IntVec::const_iterator iter = v.cbegin(); iter != v.cend(); ++iter) {
-      EXPECT_EQ(counter, *iter);
+      EXPECT_EQ(static_cast<int>(counter), *iter);
       counter++;
     }
     EXPECT_EQ(counter, len);
 
     if (len > 0) {
       EXPECT_EQ(0, v.front());
-      EXPECT_EQ(len - 1, v.back());
+      EXPECT_EQ(static_cast<int>(len - 1), v.back());
       v.pop_back();
       EXPECT_EQ(len - 1, v.size());
-      for (int i = 0; i < v.size(); ++i) {
-        EXPECT_EQ(i, v[i]);
-        EXPECT_EQ(i, v.at(i));
+      for (size_t i = 0; i < v.size(); ++i) {
+        EXPECT_EQ(static_cast<int>(i), v[i]);
+        EXPECT_EQ(static_cast<int>(i), v.at(i));
       }
     }
   }
@@ -191,7 +191,7 @@ TEST(IntVec, SimpleOps) {
 TEST(IntVec, PopBackNoOverflow) {
   IntVec v = {1};
   v.pop_back();
-  EXPECT_EQ(v.size(), 0);
+  EXPECT_EQ(v.size(), 0u);
 }
 
 TEST(IntVec, AtThrows) {
@@ -202,47 +202,47 @@ TEST(IntVec, AtThrows) {
 }
 
 TEST(IntVec, ReverseIterator) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     IntVec v;
     Fill(&v, len);
 
-    int counter = len;
+    size_t counter = len;
     for (IntVec::reverse_iterator iter = v.rbegin(); iter != v.rend(); ++iter) {
       counter--;
-      EXPECT_EQ(counter, *iter);
+      EXPECT_EQ(static_cast<int>(counter), *iter);
     }
-    EXPECT_EQ(counter, 0);
+    EXPECT_EQ(counter, 0u);
 
     counter = len;
     for (IntVec::const_reverse_iterator iter = v.rbegin(); iter != v.rend();
          ++iter) {
       counter--;
-      EXPECT_EQ(counter, *iter);
+      EXPECT_EQ(static_cast<int>(counter), *iter);
     }
-    EXPECT_EQ(counter, 0);
+    EXPECT_EQ(counter, 0u);
 
     counter = len;
     for (IntVec::const_reverse_iterator iter = v.crbegin(); iter != v.crend();
          ++iter) {
       counter--;
-      EXPECT_EQ(counter, *iter);
+      EXPECT_EQ(static_cast<int>(counter), *iter);
     }
-    EXPECT_EQ(counter, 0);
+    EXPECT_EQ(counter, 0u);
   }
 }
 
 TEST(IntVec, Erase) {
-  for (int len = 1; len < 20; len++) {
-    for (int i = 0; i < len; ++i) {
+  for (size_t len = 1; len < 20; len++) {
+    for (size_t i = 0; i < len; ++i) {
       IntVec v;
       Fill(&v, len);
       v.erase(v.begin() + i);
       EXPECT_EQ(len - 1, v.size());
-      for (int j = 0; j < i; ++j) {
-        EXPECT_EQ(j, v[j]);
+      for (size_t j = 0; j < i; ++j) {
+        EXPECT_EQ(static_cast<int>(j), v[j]);
       }
-      for (int j = i; j < len - 1; ++j) {
-        EXPECT_EQ(j + 1, v[j]);
+      for (size_t j = i; j < len - 1; ++j) {
+        EXPECT_EQ(static_cast<int>(j + 1), v[j]);
       }
     }
   }
@@ -254,7 +254,7 @@ TEST(IntVec, Hardened) {
   EXPECT_EQ(v[9], 9);
 #if !defined(NDEBUG) || ABSL_OPTION_HARDENED
   EXPECT_DEATH_IF_SUPPORTED(v[10], "");
-  EXPECT_DEATH_IF_SUPPORTED(v[-1], "");
+  EXPECT_DEATH_IF_SUPPORTED(v[static_cast<size_t>(-1)], "");
   EXPECT_DEATH_IF_SUPPORTED(v.resize(v.max_size() + 1), "");
 #endif
 }
@@ -263,43 +263,43 @@ TEST(IntVec, Hardened) {
 // should have reference counts == 0, and all others elements should have
 // reference counts == 1.
 TEST(RefCountedVec, EraseBeginEnd) {
-  for (int len = 1; len < 20; ++len) {
-    for (int erase_begin = 0; erase_begin < len; ++erase_begin) {
-      for (int erase_end = erase_begin; erase_end <= len; ++erase_end) {
+  for (size_t len = 1; len < 20; ++len) {
+    for (size_t erase_begin = 0; erase_begin < len; ++erase_begin) {
+      for (size_t erase_end = erase_begin; erase_end <= len; ++erase_end) {
         std::vector<int> counts(len, 0);
         RefCountedVec v;
-        for (int i = 0; i < len; ++i) {
-          v.push_back(RefCounted(i, &counts[i]));
+        for (size_t i = 0; i < len; ++i) {
+          v.push_back(RefCounted(static_cast<int>(i), &counts[i]));
         }
 
-        int erase_len = erase_end - erase_begin;
+        size_t erase_len = erase_end - erase_begin;
 
         v.erase(v.begin() + erase_begin, v.begin() + erase_end);
 
         EXPECT_EQ(len - erase_len, v.size());
 
         // Check the elements before the first element erased.
-        for (int i = 0; i < erase_begin; ++i) {
-          EXPECT_EQ(i, v[i].value_);
+        for (size_t i = 0; i < erase_begin; ++i) {
+          EXPECT_EQ(static_cast<int>(i), v[i].value_);
         }
 
         // Check the elements after the first element erased.
-        for (int i = erase_begin; i < v.size(); ++i) {
-          EXPECT_EQ(i + erase_len, v[i].value_);
+        for (size_t i = erase_begin; i < v.size(); ++i) {
+          EXPECT_EQ(static_cast<int>(i + erase_len), v[i].value_);
         }
 
         // Check that the elements at the beginning are preserved.
-        for (int i = 0; i < erase_begin; ++i) {
+        for (size_t i = 0; i < erase_begin; ++i) {
           EXPECT_EQ(1, counts[i]);
         }
 
         // Check that the erased elements are destroyed
-        for (int i = erase_begin; i < erase_end; ++i) {
+        for (size_t i = erase_begin; i < erase_end; ++i) {
           EXPECT_EQ(0, counts[i]);
         }
 
         // Check that the elements at the end are preserved.
-        for (int i = erase_end; i < len; ++i) {
+        for (size_t i = erase_end; i < len; ++i) {
           EXPECT_EQ(1, counts[i]);
         }
       }
@@ -378,21 +378,21 @@ TEST(InlinedVectorTest, ShrinkToFitGrowingVector) {
   absl::InlinedVector<std::pair<std::string, int>, 1> v;
 
   v.shrink_to_fit();
-  EXPECT_EQ(v.capacity(), 1);
+  EXPECT_EQ(v.capacity(), 1u);
 
   v.emplace_back("answer", 42);
   v.shrink_to_fit();
-  EXPECT_EQ(v.capacity(), 1);
+  EXPECT_EQ(v.capacity(), 1u);
 
   v.emplace_back("taxicab", 1729);
-  EXPECT_GE(v.capacity(), 2);
+  EXPECT_GE(v.capacity(), 2u);
   v.shrink_to_fit();
-  EXPECT_EQ(v.capacity(), 2);
+  EXPECT_EQ(v.capacity(), 2u);
 
   v.reserve(100);
-  EXPECT_GE(v.capacity(), 100);
+  EXPECT_GE(v.capacity(), 100u);
   v.shrink_to_fit();
-  EXPECT_EQ(v.capacity(), 2);
+  EXPECT_EQ(v.capacity(), 2u);
 }
 
 TEST(InlinedVectorTest, ShrinkToFitEdgeCases) {
@@ -400,10 +400,10 @@ TEST(InlinedVectorTest, ShrinkToFitEdgeCases) {
     absl::InlinedVector<std::pair<std::string, int>, 1> v;
     v.emplace_back("answer", 42);
     v.emplace_back("taxicab", 1729);
-    EXPECT_GE(v.capacity(), 2);
+    EXPECT_GE(v.capacity(), 2u);
     v.pop_back();
     v.shrink_to_fit();
-    EXPECT_EQ(v.capacity(), 1);
+    EXPECT_EQ(v.capacity(), 1u);
     EXPECT_EQ(v[0].first, "answer");
     EXPECT_EQ(v[0].second, 42);
   }
@@ -412,34 +412,34 @@ TEST(InlinedVectorTest, ShrinkToFitEdgeCases) {
     absl::InlinedVector<std::string, 2> v(100);
     v.resize(0);
     v.shrink_to_fit();
-    EXPECT_EQ(v.capacity(), 2);  // inlined capacity
+    EXPECT_EQ(v.capacity(), 2u);  // inlined capacity
   }
 
   {
     absl::InlinedVector<std::string, 2> v(100);
     v.resize(1);
     v.shrink_to_fit();
-    EXPECT_EQ(v.capacity(), 2);  // inlined capacity
+    EXPECT_EQ(v.capacity(), 2u);  // inlined capacity
   }
 
   {
     absl::InlinedVector<std::string, 2> v(100);
     v.resize(2);
     v.shrink_to_fit();
-    EXPECT_EQ(v.capacity(), 2);
+    EXPECT_EQ(v.capacity(), 2u);
   }
 
   {
     absl::InlinedVector<std::string, 2> v(100);
     v.resize(3);
     v.shrink_to_fit();
-    EXPECT_EQ(v.capacity(), 3);
+    EXPECT_EQ(v.capacity(), 3u);
   }
 }
 
 TEST(IntVec, Insert) {
-  for (int len = 0; len < 20; len++) {
-    for (int pos = 0; pos <= len; pos++) {
+  for (size_t len = 0; len < 20; len++) {
+    for (ptrdiff_t pos = 0; pos <= static_cast<ptrdiff_t>(len); pos++) {
       {
         // Single element
         std::vector<int> std_v;
@@ -527,16 +527,16 @@ TEST(IntVec, Insert) {
 TEST(RefCountedVec, InsertConstructorDestructor) {
   // Make sure the proper construction/destruction happen during insert
   // operations.
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     SCOPED_TRACE(len);
-    for (int pos = 0; pos <= len; pos++) {
+    for (size_t pos = 0; pos <= len; pos++) {
       SCOPED_TRACE(pos);
       std::vector<int> counts(len, 0);
       int inserted_count = 0;
       RefCountedVec v;
-      for (int i = 0; i < len; ++i) {
+      for (size_t i = 0; i < len; ++i) {
         SCOPED_TRACE(i);
-        v.push_back(RefCounted(i, &counts[i]));
+        v.push_back(RefCounted(static_cast<int>(i), &counts[i]));
       }
 
       EXPECT_THAT(counts, Each(Eq(1)));
@@ -553,20 +553,20 @@ TEST(RefCountedVec, InsertConstructorDestructor) {
 }
 
 TEST(IntVec, Resize) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     IntVec v;
     Fill(&v, len);
 
     // Try resizing up and down by k elements
     static const int kResizeElem = 1000000;
-    for (int k = 0; k < 10; k++) {
+    for (size_t k = 0; k < 10; k++) {
       // Enlarging resize
       v.resize(len + k, kResizeElem);
       EXPECT_EQ(len + k, v.size());
       EXPECT_LE(len + k, v.capacity());
-      for (int i = 0; i < len + k; i++) {
+      for (size_t i = 0; i < len + k; i++) {
         if (i < len) {
-          EXPECT_EQ(i, v[i]);
+          EXPECT_EQ(static_cast<int>(i), v[i]);
         } else {
           EXPECT_EQ(kResizeElem, v[i]);
         }
@@ -576,26 +576,26 @@ TEST(IntVec, Resize) {
       v.resize(len, kResizeElem);
       EXPECT_EQ(len, v.size());
       EXPECT_LE(len, v.capacity());
-      for (int i = 0; i < len; i++) {
-        EXPECT_EQ(i, v[i]);
+      for (size_t i = 0; i < len; i++) {
+        EXPECT_EQ(static_cast<int>(i), v[i]);
       }
     }
   }
 }
 
 TEST(IntVec, InitWithLength) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     IntVec v(len, 7);
     EXPECT_EQ(len, v.size());
     EXPECT_LE(len, v.capacity());
-    for (int i = 0; i < len; i++) {
+    for (size_t i = 0; i < len; i++) {
       EXPECT_EQ(7, v[i]);
     }
   }
 }
 
 TEST(IntVec, CopyConstructorAndAssignment) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     IntVec v;
     Fill(&v, len);
     EXPECT_EQ(len, v.size());
@@ -604,7 +604,7 @@ TEST(IntVec, CopyConstructorAndAssignment) {
     IntVec v2(v);
     EXPECT_TRUE(v == v2) << PrintToString(v) << PrintToString(v2);
 
-    for (int start_len = 0; start_len < 20; start_len++) {
+    for (size_t start_len = 0; start_len < 20; start_len++) {
       IntVec v3;
       Fill(&v3, start_len, 99);  // Add dummy elements that should go away
       v3 = v;
@@ -614,7 +614,7 @@ TEST(IntVec, CopyConstructorAndAssignment) {
 }
 
 TEST(IntVec, AliasingCopyAssignment) {
-  for (int len = 0; len < 20; ++len) {
+  for (size_t len = 0; len < 20; ++len) {
     IntVec original;
     Fill(&original, len);
     IntVec dup = original;
@@ -624,9 +624,9 @@ TEST(IntVec, AliasingCopyAssignment) {
 }
 
 TEST(IntVec, MoveConstructorAndAssignment) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     IntVec v_in;
-    const int inlined_capacity = v_in.capacity();
+    const size_t inlined_capacity = v_in.capacity();
     Fill(&v_in, len);
     EXPECT_EQ(len, v_in.size());
     EXPECT_LE(len, v_in.capacity());
@@ -643,7 +643,7 @@ TEST(IntVec, MoveConstructorAndAssignment) {
         EXPECT_FALSE(v_out.data() == old_data);
       }
     }
-    for (int start_len = 0; start_len < 20; start_len++) {
+    for (size_t start_len = 0; start_len < 20; start_len++) {
       IntVec v_out;
       Fill(&v_out, start_len, 99);  // Add dummy elements that should go away
       IntVec v_temp(v_in);
@@ -682,10 +682,10 @@ class NotTriviallyDestructible {
 };
 
 TEST(AliasingTest, Emplace) {
-  for (int i = 2; i < 20; ++i) {
+  for (size_t i = 2; i < 20; ++i) {
     absl::InlinedVector<NotTriviallyDestructible, 10> vec;
-    for (int j = 0; j < i; ++j) {
-      vec.push_back(NotTriviallyDestructible(j));
+    for (size_t j = 0; j < i; ++j) {
+      vec.push_back(NotTriviallyDestructible(static_cast<int>(j)));
     }
     vec.emplace(vec.begin(), vec[0]);
     EXPECT_EQ(vec[0], vec[1]);
@@ -697,12 +697,12 @@ TEST(AliasingTest, Emplace) {
 }
 
 TEST(AliasingTest, InsertWithCount) {
-  for (int i = 1; i < 20; ++i) {
+  for (size_t i = 1; i < 20; ++i) {
     absl::InlinedVector<NotTriviallyDestructible, 10> vec;
-    for (int j = 0; j < i; ++j) {
-      vec.push_back(NotTriviallyDestructible(j));
+    for (size_t j = 0; j < i; ++j) {
+      vec.push_back(NotTriviallyDestructible(static_cast<int>(j)));
     }
-    for (int n = 0; n < 5; ++n) {
+    for (size_t n = 0; n < 5; ++n) {
       // We use back where we can because it's guaranteed to become invalidated
       vec.insert(vec.begin(), n, vec.back());
       auto b = vec.begin();
@@ -760,22 +760,22 @@ TEST(OverheadTest, Storage) {
 }
 
 TEST(IntVec, Clear) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     SCOPED_TRACE(len);
     IntVec v;
     Fill(&v, len);
     v.clear();
-    EXPECT_EQ(0, v.size());
+    EXPECT_EQ(0u, v.size());
     EXPECT_EQ(v.begin(), v.end());
   }
 }
 
 TEST(IntVec, Reserve) {
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     IntVec v;
     Fill(&v, len);
 
-    for (int newlen = 0; newlen < 100; newlen++) {
+    for (size_t newlen = 0; newlen < 100; newlen++) {
       const int* start_rep = v.data();
       v.reserve(newlen);
       const int* final_rep = v.data();
@@ -842,9 +842,9 @@ TEST(StringVec, SelfMove) {
 }
 
 TEST(IntVec, Swap) {
-  for (int l1 = 0; l1 < 20; l1++) {
+  for (size_t l1 = 0; l1 < 20; l1++) {
     SCOPED_TRACE(l1);
-    for (int l2 = 0; l2 < 20; l2++) {
+    for (size_t l2 = 0; l2 < 20; l2++) {
       SCOPED_TRACE(l2);
       IntVec a = Fill(l1, 0);
       IntVec b = Fill(l2, 100);
@@ -854,13 +854,13 @@ TEST(IntVec, Swap) {
       }
       EXPECT_EQ(l1, b.size());
       EXPECT_EQ(l2, a.size());
-      for (int i = 0; i < l1; i++) {
+      for (size_t i = 0; i < l1; i++) {
         SCOPED_TRACE(i);
-        EXPECT_EQ(i, b[i]);
+        EXPECT_EQ(static_cast<int>(i), b[i]);
       }
-      for (int i = 0; i < l2; i++) {
+      for (size_t i = 0; i < l2; i++) {
         SCOPED_TRACE(i);
-        EXPECT_EQ(100 + i, a[i]);
+        EXPECT_EQ(100 + static_cast<int>(i), a[i]);
       }
     }
   }
@@ -869,46 +869,48 @@ TEST(IntVec, Swap) {
 TYPED_TEST_P(InstanceTest, Swap) {
   using Instance = TypeParam;
   using InstanceVec = absl::InlinedVector<Instance, 8>;
-  for (int l1 = 0; l1 < 20; l1++) {
+  for (size_t l1 = 0; l1 < 20; l1++) {
     SCOPED_TRACE(l1);
-    for (int l2 = 0; l2 < 20; l2++) {
+    for (size_t l2 = 0; l2 < 20; l2++) {
       SCOPED_TRACE(l2);
       InstanceTracker tracker;
       InstanceVec a, b;
       const size_t inlined_capacity = a.capacity();
       auto min_len = std::min(l1, l2);
       auto max_len = std::max(l1, l2);
-      for (int i = 0; i < l1; i++) a.push_back(Instance(i));
-      for (int i = 0; i < l2; i++) b.push_back(Instance(100 + i));
-      EXPECT_EQ(tracker.instances(), l1 + l2);
+      for (size_t i = 0; i < l1; i++)
+        a.push_back(Instance(static_cast<int>(i)));
+      for (size_t i = 0; i < l2; i++)
+        b.push_back(Instance(100 + static_cast<int>(i)));
+      EXPECT_EQ(tracker.instances(), static_cast<int>(l1 + l2));
       tracker.ResetCopiesMovesSwaps();
       {
         using std::swap;
         swap(a, b);
       }
-      EXPECT_EQ(tracker.instances(), l1 + l2);
+      EXPECT_EQ(tracker.instances(), static_cast<int>(l1 + l2));
       if (a.size() > inlined_capacity && b.size() > inlined_capacity) {
         EXPECT_EQ(tracker.swaps(), 0);  // Allocations are swapped.
         EXPECT_EQ(tracker.moves(), 0);
       } else if (a.size() <= inlined_capacity && b.size() <= inlined_capacity) {
-        EXPECT_EQ(tracker.swaps(), min_len);
+        EXPECT_EQ(tracker.swaps(), static_cast<int>(min_len));
         EXPECT_EQ((tracker.moves() ? tracker.moves() : tracker.copies()),
-                  max_len - min_len);
+                  static_cast<int>(max_len - min_len));
       } else {
         // One is allocated and the other isn't. The allocation is transferred
         // without copying elements, and the inlined instances are copied/moved.
         EXPECT_EQ(tracker.swaps(), 0);
         EXPECT_EQ((tracker.moves() ? tracker.moves() : tracker.copies()),
-                  min_len);
+                  static_cast<int>(min_len));
       }
 
       EXPECT_EQ(l1, b.size());
       EXPECT_EQ(l2, a.size());
-      for (int i = 0; i < l1; i++) {
-        EXPECT_EQ(i, b[i].value());
+      for (size_t i = 0; i < l1; i++) {
+        EXPECT_EQ(static_cast<int>(i), b[i].value());
       }
-      for (int i = 0; i < l2; i++) {
-        EXPECT_EQ(100 + i, a[i].value());
+      for (size_t i = 0; i < l2; i++) {
+        EXPECT_EQ(100 + static_cast<int>(i), a[i].value());
       }
     }
   }
@@ -937,9 +939,9 @@ TEST(IntVec, EqualAndNotEqual) {
 
   a.clear();
   b.clear();
-  for (int i = 0; i < 100; i++) {
-    a.push_back(i);
-    b.push_back(i);
+  for (size_t i = 0; i < 100; i++) {
+    a.push_back(static_cast<int>(i));
+    b.push_back(static_cast<int>(i));
     EXPECT_TRUE(a == b);
     EXPECT_FALSE(a != b);
 
@@ -978,26 +980,26 @@ TYPED_TEST_P(InstanceTest, CountConstructorsDestructors) {
   using Instance = TypeParam;
   using InstanceVec = absl::InlinedVector<Instance, 8>;
   InstanceTracker tracker;
-  for (int len = 0; len < 20; len++) {
+  for (size_t len = 0; len < 20; len++) {
     SCOPED_TRACE(len);
     tracker.ResetCopiesMovesSwaps();
 
     InstanceVec v;
     const size_t inlined_capacity = v.capacity();
-    for (int i = 0; i < len; i++) {
-      v.push_back(Instance(i));
+    for (size_t i = 0; i < len; i++) {
+      v.push_back(Instance(static_cast<int>(i)));
     }
-    EXPECT_EQ(tracker.instances(), len);
+    EXPECT_EQ(tracker.instances(), static_cast<int>(len));
     EXPECT_GE(tracker.copies() + tracker.moves(),
-              len);  // More due to reallocation.
+              static_cast<int>(len));  // More due to reallocation.
     tracker.ResetCopiesMovesSwaps();
 
     // Enlarging resize() must construct some objects
     tracker.ResetCopiesMovesSwaps();
     v.resize(len + 10, Instance(100));
-    EXPECT_EQ(tracker.instances(), len + 10);
+    EXPECT_EQ(tracker.instances(), static_cast<int>(len) + 10);
     if (len <= inlined_capacity && len + 10 > inlined_capacity) {
-      EXPECT_EQ(tracker.copies() + tracker.moves(), 10 + len);
+      EXPECT_EQ(tracker.copies() + tracker.moves(), 10 + static_cast<int>(len));
     } else {
       // Only specify a minimum number of copies + moves. We don't want to
       // depend on the reallocation policy here.
@@ -1008,29 +1010,30 @@ TYPED_TEST_P(InstanceTest, CountConstructorsDestructors) {
     // Shrinking resize() must destroy some objects
     tracker.ResetCopiesMovesSwaps();
     v.resize(len, Instance(100));
-    EXPECT_EQ(tracker.instances(), len);
+    EXPECT_EQ(tracker.instances(), static_cast<int>(len));
     EXPECT_EQ(tracker.copies(), 0);
     EXPECT_EQ(tracker.moves(), 0);
 
     // reserve() must not increase the number of initialized objects
     SCOPED_TRACE("reserve");
     v.reserve(len + 1000);
-    EXPECT_EQ(tracker.instances(), len);
-    EXPECT_EQ(tracker.copies() + tracker.moves(), len);
+    EXPECT_EQ(tracker.instances(), static_cast<int>(len));
+    EXPECT_EQ(tracker.copies() + tracker.moves(), static_cast<int>(len));
 
     // pop_back() and erase() must destroy one object
     if (len > 0) {
       tracker.ResetCopiesMovesSwaps();
       v.pop_back();
-      EXPECT_EQ(tracker.instances(), len - 1);
+      EXPECT_EQ(tracker.instances(), static_cast<int>(len) - 1);
       EXPECT_EQ(tracker.copies(), 0);
       EXPECT_EQ(tracker.moves(), 0);
 
       if (!v.empty()) {
         tracker.ResetCopiesMovesSwaps();
         v.erase(v.begin());
-        EXPECT_EQ(tracker.instances(), len - 2);
-        EXPECT_EQ(tracker.copies() + tracker.moves(), len - 2);
+        EXPECT_EQ(tracker.instances(), static_cast<int>(len) - 2);
+        EXPECT_EQ(tracker.copies() + tracker.moves(),
+                  static_cast<int>(len) - 2);
       }
     }
 
@@ -1087,12 +1090,12 @@ TYPED_TEST_P(InstanceTest, CountConstructorsDestructorsOnMoveConstruction) {
     tracker.ResetCopiesMovesSwaps();
     {
       InstanceVec v_copy(std::move(v));
-      if (len > inlined_capacity) {
+      if (static_cast<size_t>(len) > inlined_capacity) {
         // Allocation is moved as a whole.
         EXPECT_EQ(tracker.instances(), len);
         EXPECT_EQ(tracker.live_instances(), len);
         // Tests an implementation detail, don't rely on this in your code.
-        EXPECT_EQ(v.size(), 0);  // NOLINT misc-use-after-move
+        EXPECT_EQ(v.size(), 0u);  // NOLINT misc-use-after-move
         EXPECT_EQ(tracker.copies(), 0);
         EXPECT_EQ(tracker.moves(), 0);
       } else {
@@ -1158,7 +1161,7 @@ TYPED_TEST_P(InstanceTest, CountConstructorsDestructorsOnMoveAssignment) {
       tracker.ResetCopiesMovesSwaps();
 
       InstanceVec longer, shorter;
-      const int inlined_capacity = longer.capacity();
+      const size_t inlined_capacity = longer.capacity();
       for (int i = 0; i < len; i++) {
         longer.push_back(Instance(i));
         shorter.push_back(Instance(i));
@@ -1177,7 +1180,7 @@ TYPED_TEST_P(InstanceTest, CountConstructorsDestructorsOnMoveAssignment) {
         src_len = len;
         longer = std::move(shorter);
       }
-      if (src_len > inlined_capacity) {
+      if (static_cast<size_t>(src_len) > inlined_capacity) {
         // Allocation moved as a whole.
         EXPECT_EQ(tracker.instances(), src_len);
         EXPECT_EQ(tracker.live_instances(), src_len);
@@ -1210,10 +1213,10 @@ TEST(CountElemAssign, SimpleTypeWithInlineBacking) {
     absl::InlinedVector<int, 2> v(original_contents.begin(),
                                   original_contents.end());
     v.assign(2, 123);
-    EXPECT_THAT(v, AllOf(SizeIs(2), ElementsAre(123, 123)));
+    EXPECT_THAT(v, AllOf(SizeIs(2u), ElementsAre(123, 123)));
     if (original_size <= 2) {
       // If the original had inline backing, it should stay inline.
-      EXPECT_EQ(2, v.capacity());
+      EXPECT_EQ(2u, v.capacity());
     }
   }
 }
@@ -1227,7 +1230,7 @@ TEST(CountElemAssign, SimpleTypeWithAllocation) {
     absl::InlinedVector<int, 2> v(original_contents.begin(),
                                   original_contents.end());
     v.assign(3, 123);
-    EXPECT_THAT(v, AllOf(SizeIs(3), ElementsAre(123, 123, 123)));
+    EXPECT_THAT(v, AllOf(SizeIs(3u), ElementsAre(123, 123, 123)));
     EXPECT_LE(v.size(), v.capacity());
   }
 }
@@ -1242,10 +1245,10 @@ TYPED_TEST_P(InstanceTest, CountElemAssignInlineBacking) {
     absl::InlinedVector<Instance, 2> v(original_contents.begin(),
                                        original_contents.end());
     v.assign(2, Instance(123));
-    EXPECT_THAT(v, AllOf(SizeIs(2), ElementsAre(ValueIs(123), ValueIs(123))));
+    EXPECT_THAT(v, AllOf(SizeIs(2u), ElementsAre(ValueIs(123), ValueIs(123))));
     if (original_size <= 2) {
       // If the original had inline backing, it should stay inline.
-      EXPECT_EQ(2, v.capacity());
+      EXPECT_EQ(2u, v.capacity());
     }
   }
 }
@@ -1260,8 +1263,8 @@ void InstanceCountElemAssignWithAllocationTest() {
     absl::InlinedVector<Instance, 2> v(original_contents.begin(),
                                        original_contents.end());
     v.assign(3, Instance(123));
-    EXPECT_THAT(v, AllOf(SizeIs(3), ElementsAre(ValueIs(123), ValueIs(123),
-                                                ValueIs(123))));
+    EXPECT_THAT(v, AllOf(SizeIs(3u), ElementsAre(ValueIs(123), ValueIs(123),
+                                                 ValueIs(123))));
     EXPECT_LE(v.size(), v.capacity());
   }
 }
@@ -1276,16 +1279,17 @@ TEST(RangedConstructor, SimpleType) {
   std::vector<int> source_v = {4, 5, 6};
   // First try to fit in inline backing
   absl::InlinedVector<int, 4> v(source_v.begin(), source_v.end());
-  EXPECT_EQ(3, v.size());
-  EXPECT_EQ(4, v.capacity());  // Indication that we're still on inlined storage
+  EXPECT_EQ(3u, v.size());
+  EXPECT_EQ(4u,
+            v.capacity());  // Indication that we're still on inlined storage
   EXPECT_EQ(4, v[0]);
   EXPECT_EQ(5, v[1]);
   EXPECT_EQ(6, v[2]);
 
   // Now, force a re-allocate
   absl::InlinedVector<int, 2> realloc_v(source_v.begin(), source_v.end());
-  EXPECT_EQ(3, realloc_v.size());
-  EXPECT_LT(2, realloc_v.capacity());
+  EXPECT_EQ(3u, realloc_v.size());
+  EXPECT_LT(2u, realloc_v.capacity());
   EXPECT_EQ(4, realloc_v[0]);
   EXPECT_EQ(5, realloc_v[1]);
   EXPECT_EQ(6, realloc_v[2]);
@@ -1300,8 +1304,8 @@ void InstanceRangedConstructorTestForContainer() {
   tracker.ResetCopiesMovesSwaps();
   absl::InlinedVector<Instance, inlined_capacity> v(source_v.begin(),
                                                     source_v.end());
-  EXPECT_EQ(2, v.size());
-  EXPECT_LT(1, v.capacity());
+  EXPECT_EQ(2u, v.size());
+  EXPECT_LT(1u, v.capacity());
   EXPECT_EQ(0, v[0].value());
   EXPECT_EQ(1, v[1].value());
   EXPECT_EQ(tracker.copies(), 2);
@@ -1360,12 +1364,12 @@ TEST(RangedAssign, SimpleType) {
     // Original contents are [12345, 12345, ...]
     std::vector<int> original_contents(original_size, 12345);
 
-    for (size_t target_size = 0; target_size <= 5; ++target_size) {
+    for (int target_size = 0; target_size <= 5; ++target_size) {
       SCOPED_TRACE(target_size);
 
       // New contents are [3, 4, ...]
       std::vector<int> new_contents;
-      for (size_t i = 0; i < target_size; ++i) {
+      for (int i = 0; i < target_size; ++i) {
         new_contents.push_back(i + 3);
       }
 
@@ -1377,7 +1381,7 @@ TEST(RangedAssign, SimpleType) {
       EXPECT_LE(new_contents.size(), v.capacity());
       if (target_size <= 3 && original_size <= 3) {
         // Storage should stay inline when target size is small.
-        EXPECT_EQ(3, v.capacity());
+        EXPECT_EQ(3u, v.capacity());
       }
       EXPECT_THAT(v, ElementsAreArray(new_contents));
     }
@@ -1410,7 +1414,7 @@ void InstanceRangedAssignTestForContainer() {
       // TODO(bsamwel): Test with an input iterator.
       std::vector<Instance> new_contents_in;
       for (size_t i = 0; i < target_size; ++i) {
-        new_contents_in.push_back(Instance(i + 3));
+        new_contents_in.push_back(Instance(static_cast<int>(i) + 3));
       }
       SourceContainer new_contents(new_contents_in.begin(),
                                    new_contents_in.end());
@@ -1423,7 +1427,7 @@ void InstanceRangedAssignTestForContainer() {
       EXPECT_LE(new_contents.size(), v.capacity());
       if (target_size <= 3 && original_size <= 3) {
         // Storage should stay inline when target size is small.
-        EXPECT_EQ(3, v.capacity());
+        EXPECT_EQ(3u, v.capacity());
       }
       EXPECT_TRUE(std::equal(v.begin(), v.end(), new_contents.begin(),
                              InstanceValuesEqual<Instance>));
@@ -1447,12 +1451,12 @@ TYPED_TEST_P(InstanceTest, RangedAssign) {
 
 TEST(InitializerListConstructor, SimpleTypeWithInlineBacking) {
   EXPECT_THAT((absl::InlinedVector<int, 4>{4, 5, 6}),
-              AllOf(SizeIs(3), CapacityIs(4), ElementsAre(4, 5, 6)));
+              AllOf(SizeIs(3u), CapacityIs(4u), ElementsAre(4, 5, 6)));
 }
 
 TEST(InitializerListConstructor, SimpleTypeWithReallocationRequired) {
   EXPECT_THAT((absl::InlinedVector<int, 2>{4, 5, 6}),
-              AllOf(SizeIs(3), CapacityIs(Gt(2)), ElementsAre(4, 5, 6)));
+              AllOf(SizeIs(3u), CapacityIs(Gt(2u)), ElementsAre(4, 5, 6)));
 }
 
 TEST(InitializerListConstructor, DisparateTypesInList) {
@@ -1465,14 +1469,14 @@ TEST(InitializerListConstructor, DisparateTypesInList) {
 TEST(InitializerListConstructor, ComplexTypeWithInlineBacking) {
   EXPECT_THAT((absl::InlinedVector<CopyableMovableInstance, 1>{
                   CopyableMovableInstance(0)}),
-              AllOf(SizeIs(1), CapacityIs(1), ElementsAre(ValueIs(0))));
+              AllOf(SizeIs(1u), CapacityIs(1u), ElementsAre(ValueIs(0))));
 }
 
 TEST(InitializerListConstructor, ComplexTypeWithReallocationRequired) {
-  EXPECT_THAT(
-      (absl::InlinedVector<CopyableMovableInstance, 1>{
-          CopyableMovableInstance(0), CopyableMovableInstance(1)}),
-      AllOf(SizeIs(2), CapacityIs(Gt(1)), ElementsAre(ValueIs(0), ValueIs(1))));
+  EXPECT_THAT((absl::InlinedVector<CopyableMovableInstance, 1>{
+                  CopyableMovableInstance(0), CopyableMovableInstance(1)}),
+              AllOf(SizeIs(2u), CapacityIs(Gt(1u)),
+                    ElementsAre(ValueIs(0), ValueIs(1))));
 }
 
 TEST(InitializerListAssign, SimpleTypeFitsInlineBacking) {
@@ -1482,14 +1486,14 @@ TEST(InitializerListAssign, SimpleTypeFitsInlineBacking) {
     absl::InlinedVector<int, 2> v1(original_size, 12345);
     const size_t original_capacity_v1 = v1.capacity();
     v1.assign({3});
-    EXPECT_THAT(
-        v1, AllOf(SizeIs(1), CapacityIs(original_capacity_v1), ElementsAre(3)));
+    EXPECT_THAT(v1, AllOf(SizeIs(1u), CapacityIs(original_capacity_v1),
+                          ElementsAre(3)));
 
     absl::InlinedVector<int, 2> v2(original_size, 12345);
     const size_t original_capacity_v2 = v2.capacity();
     v2 = {3};
-    EXPECT_THAT(
-        v2, AllOf(SizeIs(1), CapacityIs(original_capacity_v2), ElementsAre(3)));
+    EXPECT_THAT(v2, AllOf(SizeIs(1u), CapacityIs(original_capacity_v2),
+                          ElementsAre(3)));
   }
 }
 
@@ -1498,13 +1502,13 @@ TEST(InitializerListAssign, SimpleTypeDoesNotFitInlineBacking) {
     SCOPED_TRACE(original_size);
     absl::InlinedVector<int, 2> v1(original_size, 12345);
     v1.assign({3, 4, 5});
-    EXPECT_THAT(v1, AllOf(SizeIs(3), ElementsAre(3, 4, 5)));
-    EXPECT_LE(3, v1.capacity());
+    EXPECT_THAT(v1, AllOf(SizeIs(3u), ElementsAre(3, 4, 5)));
+    EXPECT_LE(3u, v1.capacity());
 
     absl::InlinedVector<int, 2> v2(original_size, 12345);
     v2 = {3, 4, 5};
-    EXPECT_THAT(v2, AllOf(SizeIs(3), ElementsAre(3, 4, 5)));
-    EXPECT_LE(3, v2.capacity());
+    EXPECT_THAT(v2, AllOf(SizeIs(3u), ElementsAre(3, 4, 5)));
+    EXPECT_LE(3u, v2.capacity());
   }
 }
 
@@ -1533,7 +1537,7 @@ TYPED_TEST_P(InstanceTest, InitializerListAssign) {
     absl::InlinedVector<Instance, 2> v(original_size, Instance(12345));
     const size_t original_capacity = v.capacity();
     v.assign({Instance(3)});
-    EXPECT_THAT(v, AllOf(SizeIs(1), CapacityIs(original_capacity),
+    EXPECT_THAT(v, AllOf(SizeIs(1u), CapacityIs(original_capacity),
                          ElementsAre(ValueIs(3))));
   }
   for (size_t original_size = 0; original_size <= 4; ++original_size) {
@@ -1541,8 +1545,8 @@ TYPED_TEST_P(InstanceTest, InitializerListAssign) {
     absl::InlinedVector<Instance, 2> v(original_size, Instance(12345));
     v.assign({Instance(3), Instance(4), Instance(5)});
     EXPECT_THAT(
-        v, AllOf(SizeIs(3), ElementsAre(ValueIs(3), ValueIs(4), ValueIs(5))));
-    EXPECT_LE(3, v.capacity());
+        v, AllOf(SizeIs(3u), ElementsAre(ValueIs(3), ValueIs(4), ValueIs(5))));
+    EXPECT_LE(3u, v.capacity());
   }
 }
 
@@ -1588,54 +1592,54 @@ TEST(AllocatorSupportTest, CountAllocations) {
   MyAlloc alloc(&allocated);
   {
     AllocVec ABSL_ATTRIBUTE_UNUSED v(ia, ia + 4, alloc);
-    EXPECT_THAT(allocated, 0);
+    EXPECT_THAT(allocated, Eq(0));
   }
-  EXPECT_THAT(allocated, 0);
+  EXPECT_THAT(allocated, Eq(0));
   {
     AllocVec ABSL_ATTRIBUTE_UNUSED v(ia, ia + ABSL_ARRAYSIZE(ia), alloc);
-    EXPECT_THAT(allocated, v.size() * sizeof(int));
+    EXPECT_THAT(allocated, Eq(static_cast<int64_t>(v.size() * sizeof(int))));
   }
-  EXPECT_THAT(allocated, 0);
+  EXPECT_THAT(allocated, Eq(0));
   {
     AllocVec v(4, 1, alloc);
-    EXPECT_THAT(allocated, 0);
+    EXPECT_THAT(allocated, Eq(0));
 
     int64_t allocated2 = 0;
     MyAlloc alloc2(&allocated2);
     AllocVec v2(v, alloc2);
-    EXPECT_THAT(allocated2, 0);
+    EXPECT_THAT(allocated2, Eq(0));
 
     int64_t allocated3 = 0;
     MyAlloc alloc3(&allocated3);
     AllocVec v3(std::move(v), alloc3);
-    EXPECT_THAT(allocated3, 0);
+    EXPECT_THAT(allocated3, Eq(0));
   }
   EXPECT_THAT(allocated, 0);
   {
     AllocVec v(8, 2, alloc);
-    EXPECT_THAT(allocated, v.size() * sizeof(int));
+    EXPECT_THAT(allocated, Eq(static_cast<int64_t>(v.size() * sizeof(int))));
 
     int64_t allocated2 = 0;
     MyAlloc alloc2(&allocated2);
     AllocVec v2(v, alloc2);
-    EXPECT_THAT(allocated2, v2.size() * sizeof(int));
+    EXPECT_THAT(allocated2, Eq(static_cast<int64_t>(v2.size() * sizeof(int))));
 
     int64_t allocated3 = 0;
     MyAlloc alloc3(&allocated3);
     AllocVec v3(std::move(v), alloc3);
-    EXPECT_THAT(allocated3, v3.size() * sizeof(int));
+    EXPECT_THAT(allocated3, Eq(static_cast<int64_t>(v3.size() * sizeof(int))));
   }
   EXPECT_EQ(allocated, 0);
   {
     // Test shrink_to_fit deallocations.
     AllocVec v(8, 2, alloc);
-    EXPECT_EQ(allocated, 8 * sizeof(int));
+    EXPECT_EQ(allocated, static_cast<int64_t>(8 * sizeof(int)));
     v.resize(5);
-    EXPECT_EQ(allocated, 8 * sizeof(int));
+    EXPECT_EQ(allocated, static_cast<int64_t>(8 * sizeof(int)));
     v.shrink_to_fit();
-    EXPECT_EQ(allocated, 5 * sizeof(int));
+    EXPECT_EQ(allocated, static_cast<int64_t>(5 * sizeof(int)));
     v.resize(4);
-    EXPECT_EQ(allocated, 5 * sizeof(int));
+    EXPECT_EQ(allocated, static_cast<int64_t>(5 * sizeof(int)));
     v.shrink_to_fit();
     EXPECT_EQ(allocated, 0);
   }
@@ -1654,13 +1658,17 @@ TEST(AllocatorSupportTest, SwapBothAllocated) {
     AllocVec v1(ia1, ia1 + ABSL_ARRAYSIZE(ia1), a1);
     AllocVec v2(ia2, ia2 + ABSL_ARRAYSIZE(ia2), a2);
     EXPECT_LT(v1.capacity(), v2.capacity());
-    EXPECT_THAT(allocated1, v1.capacity() * sizeof(int));
-    EXPECT_THAT(allocated2, v2.capacity() * sizeof(int));
+    EXPECT_THAT(allocated1,
+                Eq(static_cast<int64_t>(v1.capacity() * sizeof(int))));
+    EXPECT_THAT(allocated2,
+                Eq(static_cast<int64_t>(v2.capacity() * sizeof(int))));
     v1.swap(v2);
     EXPECT_THAT(v1, ElementsAreArray(ia2));
     EXPECT_THAT(v2, ElementsAreArray(ia1));
-    EXPECT_THAT(allocated1, v2.capacity() * sizeof(int));
-    EXPECT_THAT(allocated2, v1.capacity() * sizeof(int));
+    EXPECT_THAT(allocated1,
+                Eq(static_cast<int64_t>(v2.capacity() * sizeof(int))));
+    EXPECT_THAT(allocated2,
+                Eq(static_cast<int64_t>(v1.capacity() * sizeof(int))));
   }
   EXPECT_THAT(allocated1, 0);
   EXPECT_THAT(allocated2, 0);
@@ -1678,13 +1686,15 @@ TEST(AllocatorSupportTest, SwapOneAllocated) {
     MyAlloc a2(&allocated2);
     AllocVec v1(ia1, ia1 + ABSL_ARRAYSIZE(ia1), a1);
     AllocVec v2(ia2, ia2 + ABSL_ARRAYSIZE(ia2), a2);
-    EXPECT_THAT(allocated1, v1.capacity() * sizeof(int));
-    EXPECT_THAT(allocated2, 0);
+    EXPECT_THAT(allocated1,
+                Eq(static_cast<int64_t>(v1.capacity() * sizeof(int))));
+    EXPECT_THAT(allocated2, Eq(0));
     v1.swap(v2);
     EXPECT_THAT(v1, ElementsAreArray(ia2));
     EXPECT_THAT(v2, ElementsAreArray(ia1));
-    EXPECT_THAT(allocated1, v2.capacity() * sizeof(int));
-    EXPECT_THAT(allocated2, 0);
+    EXPECT_THAT(allocated1,
+                Eq(static_cast<int64_t>(v2.capacity() * sizeof(int))));
+    EXPECT_THAT(allocated2, Eq(0));
     EXPECT_TRUE(v2.get_allocator() == a1);
     EXPECT_TRUE(v1.get_allocator() == a2);
   }
@@ -1746,7 +1756,7 @@ TEST(AllocatorSupportTest, ScopedAllocatorWorksAllocated) {
 }
 
 TEST(AllocatorSupportTest, SizeAllocConstructor) {
-  constexpr int inlined_size = 4;
+  constexpr size_t inlined_size = 4;
   using Alloc = CountingAllocator<int>;
   using AllocVec = absl::InlinedVector<int, inlined_size, Alloc>;
 
@@ -1756,7 +1766,7 @@ TEST(AllocatorSupportTest, SizeAllocConstructor) {
     auto v = AllocVec(len, Alloc(&allocated));
 
     // Inline storage used; allocator should not be invoked
-    EXPECT_THAT(allocated, 0);
+    EXPECT_THAT(allocated, Eq(0));
     EXPECT_THAT(v, AllOf(SizeIs(len), Each(0)));
   }
 
@@ -1766,7 +1776,7 @@ TEST(AllocatorSupportTest, SizeAllocConstructor) {
     auto v = AllocVec(len, Alloc(&allocated));
 
     // Out of line storage used; allocation of 8 elements expected
-    EXPECT_THAT(allocated, len * sizeof(int));
+    EXPECT_THAT(allocated, Eq(static_cast<int64_t>(len * sizeof(int))));
     EXPECT_THAT(v, AllOf(SizeIs(len), Each(0)));
   }
 }
@@ -1801,9 +1811,9 @@ TEST(InlinedVectorTest, AbslHashValueWorks) {
 
   // Generate a variety of vectors some of these are small enough for the inline
   // space but are stored out of line.
-  for (int i = 0; i < 10; ++i) {
+  for (size_t i = 0; i < 10; ++i) {
     V v;
-    for (int j = 0; j < i; ++j) {
+    for (int j = 0; j < static_cast<int>(i); ++j) {
       v.push_back(j);
     }
     cases.push_back(v);
diff --git a/absl/hash/hash_test.cc b/absl/hash/hash_test.cc
index ffa45e6e..744a2e54 100644
--- a/absl/hash/hash_test.cc
+++ b/absl/hash/hash_test.cc
@@ -222,7 +222,7 @@ TEST(HashValueTest, PointerAlignment) {
     // Limit the scope to the bits we would be using for Swisstable.
     constexpr size_t kMask = (1 << (kLog2NumValues + 7)) - 1;
     size_t stuck_bits = (~bits_or | bits_and) & kMask;
-    EXPECT_EQ(stuck_bits, 0) << "0x" << std::hex << stuck_bits;
+    EXPECT_EQ(stuck_bits, 0u) << "0x" << std::hex << stuck_bits;
   }
 }
 
@@ -737,10 +737,10 @@ TEST(HashValueTest, CombinePiecewiseBuffer) {
   //
   // This test is run on a buffer that is a multiple of the stride size, and one
   // that isn't.
-  for (size_t big_buffer_size : {1024 * 2 + 512, 1024 * 3}) {
+  for (size_t big_buffer_size : {1024u * 2 + 512u, 1024u * 3}) {
     SCOPED_TRACE(big_buffer_size);
     std::string big_buffer;
-    for (int i = 0; i < big_buffer_size; ++i) {
+    for (size_t i = 0; i < big_buffer_size; ++i) {
       // Arbitrary string
       big_buffer.push_back(32 + (i * (i / 3)) % 64);
     }
@@ -1135,10 +1135,10 @@ TEST(HashTest, HashNonUniquelyRepresentedType) {
   unsigned char buffer2[kNumStructs * sizeof(StructWithPadding)];
   std::memset(buffer2, 255, sizeof(buffer2));
   auto* s2 = reinterpret_cast<StructWithPadding*>(buffer2);
-  for (int i = 0; i < kNumStructs; ++i) {
+  for (size_t i = 0; i < kNumStructs; ++i) {
     SCOPED_TRACE(i);
-    s1[i].c = s2[i].c = '0' + i;
-    s1[i].i = s2[i].i = i;
+    s1[i].c = s2[i].c = static_cast<char>('0' + i);
+    s1[i].i = s2[i].i = static_cast<int>(i);
     ASSERT_FALSE(memcmp(buffer1 + i * sizeof(StructWithPadding),
                         buffer2 + i * sizeof(StructWithPadding),
                         sizeof(StructWithPadding)) == 0)
@@ -1226,7 +1226,9 @@ struct ValueWithBoolConversion {
 namespace std {
 template <>
 struct hash<ValueWithBoolConversion> {
-  size_t operator()(ValueWithBoolConversion v) { return v.i; }
+  size_t operator()(ValueWithBoolConversion v) {
+    return static_cast<size_t>(v.i);
+  }
 };
 }  // namespace std
 
diff --git a/absl/status/statusor_test.cc b/absl/status/statusor_test.cc
index 7cae90e1..29021543 100644
--- a/absl/status/statusor_test.cc
+++ b/absl/status/statusor_test.cc
@@ -1521,7 +1521,7 @@ static absl::StatusOr<int> MakeStatus() { return 100; }
 TEST(StatusOr, TestIgnoreError) { MakeStatus().IgnoreError(); }
 
 TEST(StatusOr, EqualityOperator) {
-  constexpr int kNumCases = 4;
+  constexpr size_t kNumCases = 4;
   std::array<absl::StatusOr<int>, kNumCases> group1 = {
       absl::StatusOr<int>(1), absl::StatusOr<int>(2),
       absl::StatusOr<int>(absl::InvalidArgumentError("msg")),
@@ -1530,8 +1530,8 @@ TEST(StatusOr, EqualityOperator) {
       absl::StatusOr<int>(1), absl::StatusOr<int>(2),
       absl::StatusOr<int>(absl::InvalidArgumentError("msg")),
       absl::StatusOr<int>(absl::InternalError("msg"))};
-  for (int i = 0; i < kNumCases; ++i) {
-    for (int j = 0; j < kNumCases; ++j) {
+  for (size_t i = 0; i < kNumCases; ++i) {
+    for (size_t j = 0; j < kNumCases; ++j) {
       if (i == j) {
         EXPECT_TRUE(group1[i] == group2[j]);
         EXPECT_FALSE(group1[i] != group2[j]);
diff --git a/absl/strings/ascii_test.cc b/absl/strings/ascii_test.cc
index 83af7825..dfed114c 100644
--- a/absl/strings/ascii_test.cc
+++ b/absl/strings/ascii_test.cc
@@ -27,103 +27,99 @@ namespace {
 
 TEST(AsciiIsFoo, All) {
   for (int i = 0; i < 256; i++) {
-    if ((i >= 'a' && i <= 'z') || (i >= 'A' && i <= 'Z'))
-      EXPECT_TRUE(absl::ascii_isalpha(i)) << ": failed on " << i;
+    const auto c = static_cast<unsigned char>(i);
+    if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
+      EXPECT_TRUE(absl::ascii_isalpha(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isalpha(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isalpha(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
-    if ((i >= '0' && i <= '9'))
-      EXPECT_TRUE(absl::ascii_isdigit(i)) << ": failed on " << i;
+    const auto c = static_cast<unsigned char>(i);
+    if ((c >= '0' && c <= '9'))
+      EXPECT_TRUE(absl::ascii_isdigit(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isdigit(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isdigit(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
-    if (absl::ascii_isalpha(i) || absl::ascii_isdigit(i))
-      EXPECT_TRUE(absl::ascii_isalnum(i)) << ": failed on " << i;
+    const auto c = static_cast<unsigned char>(i);
+    if (absl::ascii_isalpha(c) || absl::ascii_isdigit(c))
+      EXPECT_TRUE(absl::ascii_isalnum(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isalnum(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isalnum(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
+    const auto c = static_cast<unsigned char>(i);
     if (i != '\0' && strchr(" \r\n\t\v\f", i))
-      EXPECT_TRUE(absl::ascii_isspace(i)) << ": failed on " << i;
+      EXPECT_TRUE(absl::ascii_isspace(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isspace(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isspace(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
+    const auto c = static_cast<unsigned char>(i);
     if (i >= 32 && i < 127)
-      EXPECT_TRUE(absl::ascii_isprint(i)) << ": failed on " << i;
+      EXPECT_TRUE(absl::ascii_isprint(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isprint(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isprint(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
-    if (absl::ascii_isprint(i) && !absl::ascii_isspace(i) &&
-        !absl::ascii_isalnum(i))
-      EXPECT_TRUE(absl::ascii_ispunct(i)) << ": failed on " << i;
-    else
-      EXPECT_TRUE(!absl::ascii_ispunct(i)) << ": failed on " << i;
+    const auto c = static_cast<unsigned char>(i);
+    if (absl::ascii_isprint(c) && !absl::ascii_isspace(c) &&
+        !absl::ascii_isalnum(c)) {
+      EXPECT_TRUE(absl::ascii_ispunct(c)) << ": failed on " << c;
+    } else {
+      EXPECT_TRUE(!absl::ascii_ispunct(c)) << ": failed on " << c;
+    }
   }
   for (int i = 0; i < 256; i++) {
+    const auto c = static_cast<unsigned char>(i);
     if (i == ' ' || i == '\t')
-      EXPECT_TRUE(absl::ascii_isblank(i)) << ": failed on " << i;
+      EXPECT_TRUE(absl::ascii_isblank(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isblank(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isblank(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
+    const auto c = static_cast<unsigned char>(i);
     if (i < 32 || i == 127)
-      EXPECT_TRUE(absl::ascii_iscntrl(i)) << ": failed on " << i;
+      EXPECT_TRUE(absl::ascii_iscntrl(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_iscntrl(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_iscntrl(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
-    if (absl::ascii_isdigit(i) || (i >= 'A' && i <= 'F') ||
-        (i >= 'a' && i <= 'f'))
-      EXPECT_TRUE(absl::ascii_isxdigit(i)) << ": failed on " << i;
-    else
-      EXPECT_TRUE(!absl::ascii_isxdigit(i)) << ": failed on " << i;
+    const auto c = static_cast<unsigned char>(i);
+    if (absl::ascii_isdigit(c) || (i >= 'A' && i <= 'F') ||
+        (i >= 'a' && i <= 'f')) {
+      EXPECT_TRUE(absl::ascii_isxdigit(c)) << ": failed on " << c;
+    } else {
+      EXPECT_TRUE(!absl::ascii_isxdigit(c)) << ": failed on " << c;
+    }
   }
   for (int i = 0; i < 256; i++) {
+    const auto c = static_cast<unsigned char>(i);
     if (i > 32 && i < 127)
-      EXPECT_TRUE(absl::ascii_isgraph(i)) << ": failed on " << i;
+      EXPECT_TRUE(absl::ascii_isgraph(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isgraph(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isgraph(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
+    const auto c = static_cast<unsigned char>(i);
     if (i >= 'A' && i <= 'Z')
-      EXPECT_TRUE(absl::ascii_isupper(i)) << ": failed on " << i;
+      EXPECT_TRUE(absl::ascii_isupper(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_isupper(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_isupper(c)) << ": failed on " << c;
   }
   for (int i = 0; i < 256; i++) {
+    const auto c = static_cast<unsigned char>(i);
     if (i >= 'a' && i <= 'z')
-      EXPECT_TRUE(absl::ascii_islower(i)) << ": failed on " << i;
+      EXPECT_TRUE(absl::ascii_islower(c)) << ": failed on " << c;
     else
-      EXPECT_TRUE(!absl::ascii_islower(i)) << ": failed on " << i;
+      EXPECT_TRUE(!absl::ascii_islower(c)) << ": failed on " << c;
   }
-  for (int i = 0; i < 128; i++) {
-    EXPECT_TRUE(absl::ascii_isascii(i)) << ": failed on " << i;
+  for (unsigned char c = 0; c < 128; c++) {
+    EXPECT_TRUE(absl::ascii_isascii(c)) << ": failed on " << c;
   }
   for (int i = 128; i < 256; i++) {
-    EXPECT_TRUE(!absl::ascii_isascii(i)) << ": failed on " << i;
-  }
-
-  // The official is* functions don't accept negative signed chars, but
-  // our absl::ascii_is* functions do.
-  for (int i = 0; i < 256; i++) {
-    signed char sc = static_cast<signed char>(static_cast<unsigned char>(i));
-    EXPECT_EQ(absl::ascii_isalpha(i), absl::ascii_isalpha(sc)) << i;
-    EXPECT_EQ(absl::ascii_isdigit(i), absl::ascii_isdigit(sc)) << i;
-    EXPECT_EQ(absl::ascii_isalnum(i), absl::ascii_isalnum(sc)) << i;
-    EXPECT_EQ(absl::ascii_isspace(i), absl::ascii_isspace(sc)) << i;
-    EXPECT_EQ(absl::ascii_ispunct(i), absl::ascii_ispunct(sc)) << i;
-    EXPECT_EQ(absl::ascii_isblank(i), absl::ascii_isblank(sc)) << i;
-    EXPECT_EQ(absl::ascii_iscntrl(i), absl::ascii_iscntrl(sc)) << i;
-    EXPECT_EQ(absl::ascii_isxdigit(i), absl::ascii_isxdigit(sc)) << i;
-    EXPECT_EQ(absl::ascii_isprint(i), absl::ascii_isprint(sc)) << i;
-    EXPECT_EQ(absl::ascii_isgraph(i), absl::ascii_isgraph(sc)) << i;
-    EXPECT_EQ(absl::ascii_isupper(i), absl::ascii_isupper(sc)) << i;
-    EXPECT_EQ(absl::ascii_islower(i), absl::ascii_islower(sc)) << i;
-    EXPECT_EQ(absl::ascii_isascii(i), absl::ascii_isascii(sc)) << i;
+    const auto c = static_cast<unsigned char>(i);
+    EXPECT_TRUE(!absl::ascii_isascii(c)) << ": failed on " << c;
   }
 }
 
@@ -137,19 +133,20 @@ TEST(AsciiIsFoo, SameAsIsFoo) {
 #endif
 
   for (int i = 0; i < 256; i++) {
-    EXPECT_EQ(isalpha(i) != 0, absl::ascii_isalpha(i)) << i;
-    EXPECT_EQ(isdigit(i) != 0, absl::ascii_isdigit(i)) << i;
-    EXPECT_EQ(isalnum(i) != 0, absl::ascii_isalnum(i)) << i;
-    EXPECT_EQ(isspace(i) != 0, absl::ascii_isspace(i)) << i;
-    EXPECT_EQ(ispunct(i) != 0, absl::ascii_ispunct(i)) << i;
-    EXPECT_EQ(isblank(i) != 0, absl::ascii_isblank(i)) << i;
-    EXPECT_EQ(iscntrl(i) != 0, absl::ascii_iscntrl(i)) << i;
-    EXPECT_EQ(isxdigit(i) != 0, absl::ascii_isxdigit(i)) << i;
-    EXPECT_EQ(isprint(i) != 0, absl::ascii_isprint(i)) << i;
-    EXPECT_EQ(isgraph(i) != 0, absl::ascii_isgraph(i)) << i;
-    EXPECT_EQ(isupper(i) != 0, absl::ascii_isupper(i)) << i;
-    EXPECT_EQ(islower(i) != 0, absl::ascii_islower(i)) << i;
-    EXPECT_EQ(isascii(i) != 0, absl::ascii_isascii(i)) << i;
+    const auto c = static_cast<unsigned char>(i);
+    EXPECT_EQ(isalpha(c) != 0, absl::ascii_isalpha(c)) << c;
+    EXPECT_EQ(isdigit(c) != 0, absl::ascii_isdigit(c)) << c;
+    EXPECT_EQ(isalnum(c) != 0, absl::ascii_isalnum(c)) << c;
+    EXPECT_EQ(isspace(c) != 0, absl::ascii_isspace(c)) << c;
+    EXPECT_EQ(ispunct(c) != 0, absl::ascii_ispunct(c)) << c;
+    EXPECT_EQ(isblank(c) != 0, absl::ascii_isblank(c)) << c;
+    EXPECT_EQ(iscntrl(c) != 0, absl::ascii_iscntrl(c)) << c;
+    EXPECT_EQ(isxdigit(c) != 0, absl::ascii_isxdigit(c)) << c;
+    EXPECT_EQ(isprint(c) != 0, absl::ascii_isprint(c)) << c;
+    EXPECT_EQ(isgraph(c) != 0, absl::ascii_isgraph(c)) << c;
+    EXPECT_EQ(isupper(c) != 0, absl::ascii_isupper(c)) << c;
+    EXPECT_EQ(islower(c) != 0, absl::ascii_islower(c)) << c;
+    EXPECT_EQ(isascii(c) != 0, absl::ascii_isascii(c)) << c;
   }
 
 #ifndef __ANDROID__
@@ -166,25 +163,20 @@ TEST(AsciiToFoo, All) {
 #endif
 
   for (int i = 0; i < 256; i++) {
-    if (absl::ascii_islower(i))
-      EXPECT_EQ(absl::ascii_toupper(i), 'A' + (i - 'a')) << i;
+    const auto c = static_cast<unsigned char>(i);
+    if (absl::ascii_islower(c))
+      EXPECT_EQ(absl::ascii_toupper(c), 'A' + (i - 'a')) << c;
     else
-      EXPECT_EQ(absl::ascii_toupper(i), static_cast<char>(i)) << i;
+      EXPECT_EQ(absl::ascii_toupper(c), static_cast<char>(i)) << c;
 
-    if (absl::ascii_isupper(i))
-      EXPECT_EQ(absl::ascii_tolower(i), 'a' + (i - 'A')) << i;
+    if (absl::ascii_isupper(c))
+      EXPECT_EQ(absl::ascii_tolower(c), 'a' + (i - 'A')) << c;
     else
-      EXPECT_EQ(absl::ascii_tolower(i), static_cast<char>(i)) << i;
+      EXPECT_EQ(absl::ascii_tolower(c), static_cast<char>(i)) << c;
 
     // These CHECKs only hold in a C locale.
-    EXPECT_EQ(static_cast<char>(tolower(i)), absl::ascii_tolower(i)) << i;
-    EXPECT_EQ(static_cast<char>(toupper(i)), absl::ascii_toupper(i)) << i;
-
-    // The official to* functions don't accept negative signed chars, but
-    // our absl::ascii_to* functions do.
-    signed char sc = static_cast<signed char>(static_cast<unsigned char>(i));
-    EXPECT_EQ(absl::ascii_tolower(i), absl::ascii_tolower(sc)) << i;
-    EXPECT_EQ(absl::ascii_toupper(i), absl::ascii_toupper(sc)) << i;
+    EXPECT_EQ(static_cast<char>(tolower(i)), absl::ascii_tolower(c)) << c;
+    EXPECT_EQ(static_cast<char>(toupper(i)), absl::ascii_toupper(c)) << c;
   }
 #ifndef __ANDROID__
   // restore the old locale.
diff --git a/absl/strings/string_view_test.cc b/absl/strings/string_view_test.cc
index 9d5463a1..990c211a 100644
--- a/absl/strings/string_view_test.cc
+++ b/absl/strings/string_view_test.cc
@@ -82,7 +82,7 @@ TEST(StringViewTest, Ctor) {
     // Null.
     absl::string_view s10;
     EXPECT_TRUE(s10.data() == nullptr);
-    EXPECT_EQ(0, s10.length());
+    EXPECT_EQ(0u, s10.length());
   }
 
   {
@@ -90,17 +90,17 @@ TEST(StringViewTest, Ctor) {
     const char* hello = "hello";
     absl::string_view s20(hello);
     EXPECT_TRUE(s20.data() == hello);
-    EXPECT_EQ(5, s20.length());
+    EXPECT_EQ(5u, s20.length());
 
     // const char* with length.
     absl::string_view s21(hello, 4);
     EXPECT_TRUE(s21.data() == hello);
-    EXPECT_EQ(4, s21.length());
+    EXPECT_EQ(4u, s21.length());
 
     // Not recommended, but valid C++
     absl::string_view s22(hello, 6);
     EXPECT_TRUE(s22.data() == hello);
-    EXPECT_EQ(6, s22.length());
+    EXPECT_EQ(6u, s22.length());
   }
 
   {
@@ -108,7 +108,7 @@ TEST(StringViewTest, Ctor) {
     std::string hola = "hola";
     absl::string_view s30(hola);
     EXPECT_TRUE(s30.data() == hola.data());
-    EXPECT_EQ(4, s30.length());
+    EXPECT_EQ(4u, s30.length());
 
     // std::string with embedded '\0'.
     hola.push_back('\0');
@@ -116,7 +116,7 @@ TEST(StringViewTest, Ctor) {
     hola.push_back('\0');
     absl::string_view s31(hola);
     EXPECT_TRUE(s31.data() == hola.data());
-    EXPECT_EQ(8, s31.length());
+    EXPECT_EQ(8u, s31.length());
   }
 
   {
@@ -165,7 +165,7 @@ TEST(StringViewTest, STLComparator) {
   map.insert(std::make_pair(p1, 0));
   map.insert(std::make_pair(p2, 1));
   map.insert(std::make_pair(p3, 2));
-  EXPECT_EQ(map.size(), 3);
+  EXPECT_EQ(map.size(), 3u);
 
   TestMap::const_iterator iter = map.begin();
   EXPECT_EQ(iter->second, 1);
@@ -183,7 +183,7 @@ TEST(StringViewTest, STLComparator) {
   EXPECT_TRUE(new_iter != map.end());
 
   map.erase(new_iter);
-  EXPECT_EQ(map.size(), 2);
+  EXPECT_EQ(map.size(), 2u);
 
   iter = map.begin();
   EXPECT_EQ(iter->second, 2);
@@ -261,11 +261,11 @@ TEST(StringViewTest, ComparisonOperators) {
 
 TEST(StringViewTest, ComparisonOperatorsByCharacterPosition) {
   std::string x;
-  for (int i = 0; i < 256; i++) {
+  for (size_t i = 0; i < 256; i++) {
     x += 'a';
     std::string y = x;
     COMPARE(true, ==, x, y);
-    for (int j = 0; j < i; j++) {
+    for (size_t j = 0; j < i; j++) {
       std::string z = x;
       z[j] = 'b';       // Differs in position 'j'
       COMPARE(false, ==, x, z);
@@ -341,12 +341,12 @@ TEST(StringViewTest, STL1) {
   EXPECT_EQ(*(c.rend() - 1), 'x');
   EXPECT_TRUE(a.rbegin() + 26 == a.rend());
 
-  EXPECT_EQ(a.size(), 26);
-  EXPECT_EQ(b.size(), 3);
-  EXPECT_EQ(c.size(), 3);
-  EXPECT_EQ(d.size(), 6);
-  EXPECT_EQ(e.size(), 0);
-  EXPECT_EQ(f.size(), 7);
+  EXPECT_EQ(a.size(), 26u);
+  EXPECT_EQ(b.size(), 3u);
+  EXPECT_EQ(c.size(), 3u);
+  EXPECT_EQ(d.size(), 6u);
+  EXPECT_EQ(e.size(), 0u);
+  EXPECT_EQ(f.size(), 7u);
 
   EXPECT_TRUE(!d.empty());
   EXPECT_TRUE(d.begin() != d.end());
@@ -356,17 +356,17 @@ TEST(StringViewTest, STL1) {
   EXPECT_TRUE(e.begin() == e.end());
 
   char buf[4] = { '%', '%', '%', '%' };
-  EXPECT_EQ(a.copy(buf, 4), 4);
+  EXPECT_EQ(a.copy(buf, 4), 4u);
   EXPECT_EQ(buf[0], a[0]);
   EXPECT_EQ(buf[1], a[1]);
   EXPECT_EQ(buf[2], a[2]);
   EXPECT_EQ(buf[3], a[3]);
-  EXPECT_EQ(a.copy(buf, 3, 7), 3);
+  EXPECT_EQ(a.copy(buf, 3, 7), 3u);
   EXPECT_EQ(buf[0], a[7]);
   EXPECT_EQ(buf[1], a[8]);
   EXPECT_EQ(buf[2], a[9]);
   EXPECT_EQ(buf[3], a[3]);
-  EXPECT_EQ(c.copy(buf, 99), 3);
+  EXPECT_EQ(c.copy(buf, 99), 3u);
   EXPECT_EQ(buf[0], c[0]);
   EXPECT_EQ(buf[1], c[1]);
   EXPECT_EQ(buf[2], c[2]);
@@ -393,22 +393,22 @@ TEST(StringViewTest, STL2) {
       7);
 
   d = absl::string_view();
-  EXPECT_EQ(d.size(), 0);
+  EXPECT_EQ(d.size(), 0u);
   EXPECT_TRUE(d.empty());
   EXPECT_TRUE(d.data() == nullptr);
   EXPECT_TRUE(d.begin() == d.end());
 
-  EXPECT_EQ(a.find(b), 0);
+  EXPECT_EQ(a.find(b), 0u);
   EXPECT_EQ(a.find(b, 1), absl::string_view::npos);
-  EXPECT_EQ(a.find(c), 23);
-  EXPECT_EQ(a.find(c, 9), 23);
+  EXPECT_EQ(a.find(c), 23u);
+  EXPECT_EQ(a.find(c, 9), 23u);
   EXPECT_EQ(a.find(c, absl::string_view::npos), absl::string_view::npos);
   EXPECT_EQ(b.find(c), absl::string_view::npos);
   EXPECT_EQ(b.find(c, absl::string_view::npos), absl::string_view::npos);
-  EXPECT_EQ(a.find(d), 0);
-  EXPECT_EQ(a.find(e), 0);
-  EXPECT_EQ(a.find(d, 12), 12);
-  EXPECT_EQ(a.find(e, 17), 17);
+  EXPECT_EQ(a.find(d), 0u);
+  EXPECT_EQ(a.find(e), 0u);
+  EXPECT_EQ(a.find(d, 12), 12u);
+  EXPECT_EQ(a.find(e, 17), 17u);
   absl::string_view g("xx not found bb");
   EXPECT_EQ(a.find(g), absl::string_view::npos);
   // empty string nonsense
@@ -427,17 +427,17 @@ TEST(StringViewTest, STL2) {
   EXPECT_EQ(e.find(d, 4), std::string().find(std::string(), 4));
   EXPECT_EQ(e.find(e, 4), std::string().find(std::string(), 4));
 
-  EXPECT_EQ(a.find('a'), 0);
-  EXPECT_EQ(a.find('c'), 2);
-  EXPECT_EQ(a.find('z'), 25);
+  EXPECT_EQ(a.find('a'), 0u);
+  EXPECT_EQ(a.find('c'), 2u);
+  EXPECT_EQ(a.find('z'), 25u);
   EXPECT_EQ(a.find('$'), absl::string_view::npos);
   EXPECT_EQ(a.find('\0'), absl::string_view::npos);
-  EXPECT_EQ(f.find('\0'), 3);
-  EXPECT_EQ(f.find('3'), 2);
-  EXPECT_EQ(f.find('5'), 5);
-  EXPECT_EQ(g.find('o'), 4);
-  EXPECT_EQ(g.find('o', 4), 4);
-  EXPECT_EQ(g.find('o', 5), 8);
+  EXPECT_EQ(f.find('\0'), 3u);
+  EXPECT_EQ(f.find('3'), 2u);
+  EXPECT_EQ(f.find('5'), 5u);
+  EXPECT_EQ(g.find('o'), 4u);
+  EXPECT_EQ(g.find('o', 4), 4u);
+  EXPECT_EQ(g.find('o', 5), 8u);
   EXPECT_EQ(a.find('b', 5), absl::string_view::npos);
   // empty string nonsense
   EXPECT_EQ(d.find('\0'), absl::string_view::npos);
@@ -449,8 +449,8 @@ TEST(StringViewTest, STL2) {
   EXPECT_EQ(d.find('x', 4), absl::string_view::npos);
   EXPECT_EQ(e.find('x', 7), absl::string_view::npos);
 
-  EXPECT_EQ(a.find(b.data(), 1, 0), 1);
-  EXPECT_EQ(a.find(c.data(), 9, 0), 9);
+  EXPECT_EQ(a.find(b.data(), 1, 0), 1u);
+  EXPECT_EQ(a.find(c.data(), 9, 0), 9u);
   EXPECT_EQ(a.find(c.data(), absl::string_view::npos, 0),
             absl::string_view::npos);
   EXPECT_EQ(b.find(c.data(), absl::string_view::npos, 0),
@@ -460,16 +460,16 @@ TEST(StringViewTest, STL2) {
   EXPECT_EQ(e.find(b.data(), 7, 0), absl::string_view::npos);
 
   EXPECT_EQ(a.find(b.data(), 1), absl::string_view::npos);
-  EXPECT_EQ(a.find(c.data(), 9), 23);
+  EXPECT_EQ(a.find(c.data(), 9), 23u);
   EXPECT_EQ(a.find(c.data(), absl::string_view::npos), absl::string_view::npos);
   EXPECT_EQ(b.find(c.data(), absl::string_view::npos), absl::string_view::npos);
   // empty string nonsense
   EXPECT_EQ(d.find(b.data(), 4), absl::string_view::npos);
   EXPECT_EQ(e.find(b.data(), 7), absl::string_view::npos);
 
-  EXPECT_EQ(a.rfind(b), 0);
-  EXPECT_EQ(a.rfind(b, 1), 0);
-  EXPECT_EQ(a.rfind(c), 23);
+  EXPECT_EQ(a.rfind(b), 0u);
+  EXPECT_EQ(a.rfind(b, 1), 0u);
+  EXPECT_EQ(a.rfind(c), 23u);
   EXPECT_EQ(a.rfind(c, 22), absl::string_view::npos);
   EXPECT_EQ(a.rfind(c, 1), absl::string_view::npos);
   EXPECT_EQ(a.rfind(c, 0), absl::string_view::npos);
@@ -477,8 +477,8 @@ TEST(StringViewTest, STL2) {
   EXPECT_EQ(b.rfind(c, 0), absl::string_view::npos);
   EXPECT_EQ(a.rfind(d), std::string(a).rfind(std::string()));
   EXPECT_EQ(a.rfind(e), std::string(a).rfind(std::string()));
-  EXPECT_EQ(a.rfind(d, 12), 12);
-  EXPECT_EQ(a.rfind(e, 17), 17);
+  EXPECT_EQ(a.rfind(d, 12), 12u);
+  EXPECT_EQ(a.rfind(e, 17), 17u);
   EXPECT_EQ(a.rfind(g), absl::string_view::npos);
   EXPECT_EQ(d.rfind(b), absl::string_view::npos);
   EXPECT_EQ(e.rfind(b), absl::string_view::npos);
@@ -494,28 +494,28 @@ TEST(StringViewTest, STL2) {
   EXPECT_EQ(d.rfind(e), std::string().rfind(std::string()));
   EXPECT_EQ(e.rfind(e), std::string().rfind(std::string()));
 
-  EXPECT_EQ(g.rfind('o'), 8);
+  EXPECT_EQ(g.rfind('o'), 8u);
   EXPECT_EQ(g.rfind('q'), absl::string_view::npos);
-  EXPECT_EQ(g.rfind('o', 8), 8);
-  EXPECT_EQ(g.rfind('o', 7), 4);
+  EXPECT_EQ(g.rfind('o', 8), 8u);
+  EXPECT_EQ(g.rfind('o', 7), 4u);
   EXPECT_EQ(g.rfind('o', 3), absl::string_view::npos);
-  EXPECT_EQ(f.rfind('\0'), 3);
-  EXPECT_EQ(f.rfind('\0', 12), 3);
-  EXPECT_EQ(f.rfind('3'), 2);
-  EXPECT_EQ(f.rfind('5'), 5);
+  EXPECT_EQ(f.rfind('\0'), 3u);
+  EXPECT_EQ(f.rfind('\0', 12), 3u);
+  EXPECT_EQ(f.rfind('3'), 2u);
+  EXPECT_EQ(f.rfind('5'), 5u);
   // empty string nonsense
   EXPECT_EQ(d.rfind('o'), absl::string_view::npos);
   EXPECT_EQ(e.rfind('o'), absl::string_view::npos);
   EXPECT_EQ(d.rfind('o', 4), absl::string_view::npos);
   EXPECT_EQ(e.rfind('o', 7), absl::string_view::npos);
 
-  EXPECT_EQ(a.rfind(b.data(), 1, 0), 1);
-  EXPECT_EQ(a.rfind(c.data(), 22, 0), 22);
-  EXPECT_EQ(a.rfind(c.data(), 1, 0), 1);
-  EXPECT_EQ(a.rfind(c.data(), 0, 0), 0);
-  EXPECT_EQ(b.rfind(c.data(), 0, 0), 0);
-  EXPECT_EQ(d.rfind(b.data(), 4, 0), 0);
-  EXPECT_EQ(e.rfind(b.data(), 7, 0), 0);
+  EXPECT_EQ(a.rfind(b.data(), 1, 0), 1u);
+  EXPECT_EQ(a.rfind(c.data(), 22, 0), 22u);
+  EXPECT_EQ(a.rfind(c.data(), 1, 0), 1u);
+  EXPECT_EQ(a.rfind(c.data(), 0, 0), 0u);
+  EXPECT_EQ(b.rfind(c.data(), 0, 0), 0u);
+  EXPECT_EQ(d.rfind(b.data(), 4, 0), 0u);
+  EXPECT_EQ(e.rfind(b.data(), 7, 0), 0u);
 }
 
 // Continued from STL2
@@ -533,18 +533,18 @@ TEST(StringViewTest, STL2FindFirst) {
   absl::string_view g("xx not found bb");
 
   d = absl::string_view();
-  EXPECT_EQ(a.find_first_of(b), 0);
-  EXPECT_EQ(a.find_first_of(b, 0), 0);
-  EXPECT_EQ(a.find_first_of(b, 1), 1);
-  EXPECT_EQ(a.find_first_of(b, 2), 2);
+  EXPECT_EQ(a.find_first_of(b), 0u);
+  EXPECT_EQ(a.find_first_of(b, 0), 0u);
+  EXPECT_EQ(a.find_first_of(b, 1), 1u);
+  EXPECT_EQ(a.find_first_of(b, 2), 2u);
   EXPECT_EQ(a.find_first_of(b, 3), absl::string_view::npos);
-  EXPECT_EQ(a.find_first_of(c), 23);
-  EXPECT_EQ(a.find_first_of(c, 23), 23);
-  EXPECT_EQ(a.find_first_of(c, 24), 24);
-  EXPECT_EQ(a.find_first_of(c, 25), 25);
+  EXPECT_EQ(a.find_first_of(c), 23u);
+  EXPECT_EQ(a.find_first_of(c, 23), 23u);
+  EXPECT_EQ(a.find_first_of(c, 24), 24u);
+  EXPECT_EQ(a.find_first_of(c, 25), 25u);
   EXPECT_EQ(a.find_first_of(c, 26), absl::string_view::npos);
-  EXPECT_EQ(g.find_first_of(b), 13);
-  EXPECT_EQ(g.find_first_of(c), 0);
+  EXPECT_EQ(g.find_first_of(b), 13u);
+  EXPECT_EQ(g.find_first_of(c), 0u);
   EXPECT_EQ(a.find_first_of(f), absl::string_view::npos);
   EXPECT_EQ(f.find_first_of(a), absl::string_view::npos);
   // empty string nonsense
@@ -557,19 +557,19 @@ TEST(StringViewTest, STL2FindFirst) {
   EXPECT_EQ(d.find_first_of(e), absl::string_view::npos);
   EXPECT_EQ(e.find_first_of(e), absl::string_view::npos);
 
-  EXPECT_EQ(a.find_first_not_of(b), 3);
-  EXPECT_EQ(a.find_first_not_of(c), 0);
+  EXPECT_EQ(a.find_first_not_of(b), 3u);
+  EXPECT_EQ(a.find_first_not_of(c), 0u);
   EXPECT_EQ(b.find_first_not_of(a), absl::string_view::npos);
   EXPECT_EQ(c.find_first_not_of(a), absl::string_view::npos);
-  EXPECT_EQ(f.find_first_not_of(a), 0);
-  EXPECT_EQ(a.find_first_not_of(f), 0);
-  EXPECT_EQ(a.find_first_not_of(d), 0);
-  EXPECT_EQ(a.find_first_not_of(e), 0);
+  EXPECT_EQ(f.find_first_not_of(a), 0u);
+  EXPECT_EQ(a.find_first_not_of(f), 0u);
+  EXPECT_EQ(a.find_first_not_of(d), 0u);
+  EXPECT_EQ(a.find_first_not_of(e), 0u);
   // empty string nonsense
-  EXPECT_EQ(a.find_first_not_of(d), 0);
-  EXPECT_EQ(a.find_first_not_of(e), 0);
-  EXPECT_EQ(a.find_first_not_of(d, 1), 1);
-  EXPECT_EQ(a.find_first_not_of(e, 1), 1);
+  EXPECT_EQ(a.find_first_not_of(d), 0u);
+  EXPECT_EQ(a.find_first_not_of(e), 0u);
+  EXPECT_EQ(a.find_first_not_of(d, 1), 1u);
+  EXPECT_EQ(a.find_first_not_of(e, 1), 1u);
   EXPECT_EQ(a.find_first_not_of(d, a.size() - 1), a.size() - 1);
   EXPECT_EQ(a.find_first_not_of(e, a.size() - 1), a.size() - 1);
   EXPECT_EQ(a.find_first_not_of(d, a.size()), absl::string_view::npos);
@@ -588,11 +588,11 @@ TEST(StringViewTest, STL2FindFirst) {
   absl::string_view h("====");
   EXPECT_EQ(h.find_first_not_of('='), absl::string_view::npos);
   EXPECT_EQ(h.find_first_not_of('=', 3), absl::string_view::npos);
-  EXPECT_EQ(h.find_first_not_of('\0'), 0);
-  EXPECT_EQ(g.find_first_not_of('x'), 2);
-  EXPECT_EQ(f.find_first_not_of('\0'), 0);
-  EXPECT_EQ(f.find_first_not_of('\0', 3), 4);
-  EXPECT_EQ(f.find_first_not_of('\0', 2), 2);
+  EXPECT_EQ(h.find_first_not_of('\0'), 0u);
+  EXPECT_EQ(g.find_first_not_of('x'), 2u);
+  EXPECT_EQ(f.find_first_not_of('\0'), 0u);
+  EXPECT_EQ(f.find_first_not_of('\0', 3), 4u);
+  EXPECT_EQ(f.find_first_not_of('\0', 2), 2u);
   // empty string nonsense
   EXPECT_EQ(d.find_first_not_of('x'), absl::string_view::npos);
   EXPECT_EQ(e.find_first_not_of('x'), absl::string_view::npos);
@@ -618,20 +618,20 @@ TEST(StringViewTest, STL2FindLast) {
 
   d = absl::string_view();
   EXPECT_EQ(h.find_last_of(a), absl::string_view::npos);
-  EXPECT_EQ(g.find_last_of(a), g.size()-1);
-  EXPECT_EQ(a.find_last_of(b), 2);
-  EXPECT_EQ(a.find_last_of(c), a.size()-1);
-  EXPECT_EQ(f.find_last_of(i), 6);
-  EXPECT_EQ(a.find_last_of('a'), 0);
-  EXPECT_EQ(a.find_last_of('b'), 1);
-  EXPECT_EQ(a.find_last_of('z'), 25);
-  EXPECT_EQ(a.find_last_of('a', 5), 0);
-  EXPECT_EQ(a.find_last_of('b', 5), 1);
+  EXPECT_EQ(g.find_last_of(a), g.size() - 1);
+  EXPECT_EQ(a.find_last_of(b), 2u);
+  EXPECT_EQ(a.find_last_of(c), a.size() - 1);
+  EXPECT_EQ(f.find_last_of(i), 6u);
+  EXPECT_EQ(a.find_last_of('a'), 0u);
+  EXPECT_EQ(a.find_last_of('b'), 1u);
+  EXPECT_EQ(a.find_last_of('z'), 25u);
+  EXPECT_EQ(a.find_last_of('a', 5), 0u);
+  EXPECT_EQ(a.find_last_of('b', 5), 1u);
   EXPECT_EQ(a.find_last_of('b', 0), absl::string_view::npos);
-  EXPECT_EQ(a.find_last_of('z', 25), 25);
+  EXPECT_EQ(a.find_last_of('z', 25), 25u);
   EXPECT_EQ(a.find_last_of('z', 24), absl::string_view::npos);
-  EXPECT_EQ(f.find_last_of(i, 5), 5);
-  EXPECT_EQ(f.find_last_of(i, 6), 6);
+  EXPECT_EQ(f.find_last_of(i, 5), 5u);
+  EXPECT_EQ(f.find_last_of(i, 6), 6u);
   EXPECT_EQ(f.find_last_of(a, 4), absl::string_view::npos);
   // empty string nonsense
   EXPECT_EQ(f.find_last_of(d), absl::string_view::npos);
@@ -651,19 +651,19 @@ TEST(StringViewTest, STL2FindLast) {
   EXPECT_EQ(d.find_last_of(f, 4), absl::string_view::npos);
   EXPECT_EQ(e.find_last_of(f, 4), absl::string_view::npos);
 
-  EXPECT_EQ(a.find_last_not_of(b), a.size()-1);
-  EXPECT_EQ(a.find_last_not_of(c), 22);
+  EXPECT_EQ(a.find_last_not_of(b), a.size() - 1);
+  EXPECT_EQ(a.find_last_not_of(c), 22u);
   EXPECT_EQ(b.find_last_not_of(a), absl::string_view::npos);
   EXPECT_EQ(b.find_last_not_of(b), absl::string_view::npos);
-  EXPECT_EQ(f.find_last_not_of(i), 4);
-  EXPECT_EQ(a.find_last_not_of(c, 24), 22);
-  EXPECT_EQ(a.find_last_not_of(b, 3), 3);
+  EXPECT_EQ(f.find_last_not_of(i), 4u);
+  EXPECT_EQ(a.find_last_not_of(c, 24), 22u);
+  EXPECT_EQ(a.find_last_not_of(b, 3), 3u);
   EXPECT_EQ(a.find_last_not_of(b, 2), absl::string_view::npos);
   // empty string nonsense
-  EXPECT_EQ(f.find_last_not_of(d), f.size()-1);
-  EXPECT_EQ(f.find_last_not_of(e), f.size()-1);
-  EXPECT_EQ(f.find_last_not_of(d, 4), 4);
-  EXPECT_EQ(f.find_last_not_of(e, 4), 4);
+  EXPECT_EQ(f.find_last_not_of(d), f.size() - 1);
+  EXPECT_EQ(f.find_last_not_of(e), f.size() - 1);
+  EXPECT_EQ(f.find_last_not_of(d, 4), 4u);
+  EXPECT_EQ(f.find_last_not_of(e, 4), 4u);
   EXPECT_EQ(d.find_last_not_of(d), absl::string_view::npos);
   EXPECT_EQ(d.find_last_not_of(e), absl::string_view::npos);
   EXPECT_EQ(e.find_last_not_of(d), absl::string_view::npos);
@@ -679,10 +679,10 @@ TEST(StringViewTest, STL2FindLast) {
 
   EXPECT_EQ(h.find_last_not_of('x'), h.size() - 1);
   EXPECT_EQ(h.find_last_not_of('='), absl::string_view::npos);
-  EXPECT_EQ(b.find_last_not_of('c'), 1);
-  EXPECT_EQ(h.find_last_not_of('x', 2), 2);
+  EXPECT_EQ(b.find_last_not_of('c'), 1u);
+  EXPECT_EQ(h.find_last_not_of('x', 2), 2u);
   EXPECT_EQ(h.find_last_not_of('=', 2), absl::string_view::npos);
-  EXPECT_EQ(b.find_last_not_of('b', 1), 0);
+  EXPECT_EQ(b.find_last_not_of('b', 1), 0u);
   // empty string nonsense
   EXPECT_EQ(d.find_last_not_of('x'), absl::string_view::npos);
   EXPECT_EQ(e.find_last_not_of('x'), absl::string_view::npos);
@@ -734,7 +734,7 @@ TEST(StringViewTest, TruncSubstr) {
 TEST(StringViewTest, UTF8) {
   std::string utf8 = "\u00E1";
   std::string utf8_twice = utf8 + " " + utf8;
-  int utf8_len = strlen(utf8.data());
+  size_t utf8_len = strlen(utf8.data());
   EXPECT_EQ(utf8_len, absl::string_view(utf8_twice).find_first_of(" "));
   EXPECT_EQ(utf8_len, absl::string_view(utf8_twice).find_first_of(" \t"));
 }
@@ -879,12 +879,12 @@ TEST(StringViewTest, FrontBackEmpty) {
 TEST(StringViewTest, NULLInput) {
   absl::string_view s;
   EXPECT_EQ(s.data(), nullptr);
-  EXPECT_EQ(s.size(), 0);
+  EXPECT_EQ(s.size(), 0u);
 
 #ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
   s = absl::string_view(nullptr);
   EXPECT_EQ(s.data(), nullptr);
-  EXPECT_EQ(s.size(), 0);
+  EXPECT_EQ(s.size(), 0u);
 
   // .ToString() on a absl::string_view with nullptr should produce the empty
   // string.
@@ -959,7 +959,7 @@ TEST(StringViewTest, NullSafeStringView) {
   {
     absl::string_view s = absl::NullSafeStringView(nullptr);
     EXPECT_EQ(nullptr, s.data());
-    EXPECT_EQ(0, s.size());
+    EXPECT_EQ(0u, s.size());
     EXPECT_EQ(absl::string_view(), s);
   }
   {
@@ -975,7 +975,7 @@ TEST(StringViewTest, ConstexprNullSafeStringView) {
   {
     constexpr absl::string_view s = absl::NullSafeStringView(nullptr);
     EXPECT_EQ(nullptr, s.data());
-    EXPECT_EQ(0, s.size());
+    EXPECT_EQ(0u, s.size());
     EXPECT_EQ(absl::string_view(), s);
   }
 #if !defined(_MSC_VER) || _MSC_VER >= 1910
@@ -990,7 +990,7 @@ TEST(StringViewTest, ConstexprNullSafeStringView) {
   }
   {
     constexpr absl::string_view s = absl::NullSafeStringView("hello");
-    EXPECT_EQ(s.size(), 5);
+    EXPECT_EQ(s.size(), 5u);
     EXPECT_EQ("hello", s);
   }
 #endif
@@ -1036,7 +1036,7 @@ TEST(StringViewTest, ConstexprCompiles) {
 
 #ifdef ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR
   constexpr absl::string_view cstr_strlen("foo");
-  EXPECT_EQ(cstr_strlen.length(), 3);
+  EXPECT_EQ(cstr_strlen.length(), 3u);
   constexpr absl::string_view cstr_strlen2 = "bar";
   EXPECT_EQ(cstr_strlen2, "bar");
 
@@ -1111,7 +1111,7 @@ TEST(StringViewTest, ConstexprCompiles) {
   EXPECT_NE(cstr_ptr, nullptr);
 
   constexpr size_t sp_npos = sp.npos;
-  EXPECT_EQ(sp_npos, -1);
+  EXPECT_EQ(sp_npos, static_cast<size_t>(-1));
 }
 
 constexpr char ConstexprMethodsHelper() {
@@ -1179,7 +1179,7 @@ TEST(StringViewTest, BoundsCheck) {
   // Abseil's string_view implementation has bounds-checking in debug mode.
   absl::string_view h = "hello";
   ABSL_EXPECT_DEATH_IF_SUPPORTED(h[5], "");
-  ABSL_EXPECT_DEATH_IF_SUPPORTED(h[-1], "");
+  ABSL_EXPECT_DEATH_IF_SUPPORTED(h[static_cast<size_t>(-1)], "");
 #endif
 #endif
 }
@@ -1201,17 +1201,17 @@ TEST(FindOneCharTest, EdgeCases) {
   a.remove_prefix(1);
   a.remove_suffix(1);
 
-  EXPECT_EQ(0, a.find('x'));
-  EXPECT_EQ(0, a.find('x', 0));
-  EXPECT_EQ(4, a.find('x', 1));
-  EXPECT_EQ(4, a.find('x', 4));
+  EXPECT_EQ(0u, a.find('x'));
+  EXPECT_EQ(0u, a.find('x', 0));
+  EXPECT_EQ(4u, a.find('x', 1));
+  EXPECT_EQ(4u, a.find('x', 4));
   EXPECT_EQ(absl::string_view::npos, a.find('x', 5));
 
-  EXPECT_EQ(4, a.rfind('x'));
-  EXPECT_EQ(4, a.rfind('x', 5));
-  EXPECT_EQ(4, a.rfind('x', 4));
-  EXPECT_EQ(0, a.rfind('x', 3));
-  EXPECT_EQ(0, a.rfind('x', 0));
+  EXPECT_EQ(4u, a.rfind('x'));
+  EXPECT_EQ(4u, a.rfind('x', 5));
+  EXPECT_EQ(4u, a.rfind('x', 4));
+  EXPECT_EQ(0u, a.rfind('x', 3));
+  EXPECT_EQ(0u, a.rfind('x', 0));
 
   // Set a = "yyy".
   a.remove_prefix(1);
@@ -1239,8 +1239,8 @@ TEST(HugeStringView, TwoPointTwoGB) {
 
 #if !defined(NDEBUG) && !defined(ABSL_USES_STD_STRING_VIEW)
 TEST(NonNegativeLenTest, NonNegativeLen) {
-  ABSL_EXPECT_DEATH_IF_SUPPORTED(absl::string_view("xyz", -1),
-                                 "len <= kMaxSize");
+  ABSL_EXPECT_DEATH_IF_SUPPORTED(
+      absl::string_view("xyz", static_cast<size_t>(-1)), "len <= kMaxSize");
 }
 
 TEST(LenExceedsMaxSizeTest, LenExceedsMaxSize) {
diff --git a/absl/types/optional_test.cc b/absl/types/optional_test.cc
index 9477c150..21653a90 100644
--- a/absl/types/optional_test.cc
+++ b/absl/types/optional_test.cc
@@ -988,8 +988,8 @@ TEST(optionalTest, PointerStuff) {
   EXPECT_EQ("foo", *opt);
   const auto& opt_const = opt;
   EXPECT_EQ("foo", *opt_const);
-  EXPECT_EQ(opt->size(), 3);
-  EXPECT_EQ(opt_const->size(), 3);
+  EXPECT_EQ(opt->size(), 3u);
+  EXPECT_EQ(opt_const->size(), 3u);
 
   constexpr absl::optional<ConstexprType> opt1(1);
   static_assert((*opt1).x == ConstexprType::kCtorInt, "");
@@ -1523,7 +1523,7 @@ TEST(optionalTest, Hash) {
   for (int i = 0; i < 100; ++i) {
     hashcodes.insert(hash(i));
   }
-  EXPECT_GT(hashcodes.size(), 90);
+  EXPECT_GT(hashcodes.size(), 90u);
 
   static_assert(is_hash_enabled_for<absl::optional<int>>::value, "");
   static_assert(is_hash_enabled_for<absl::optional<Hashable>>::value, "");
diff --git a/absl/types/variant_test.cc b/absl/types/variant_test.cc
index cf237334..4cd5b7a3 100644
--- a/absl/types/variant_test.cc
+++ b/absl/types/variant_test.cc
@@ -281,7 +281,7 @@ TEST(VariantTest, TestDefaultConstructor) {
     using X = variant<int>;
     constexpr variant<int> x{};
     ASSERT_FALSE(x.valueless_by_exception());
-    ASSERT_EQ(0, x.index());
+    ASSERT_EQ(0u, x.index());
     EXPECT_EQ(0, absl::get<0>(x));
     EXPECT_TRUE(std::is_nothrow_default_constructible<X>::value);
   }
@@ -290,7 +290,7 @@ TEST(VariantTest, TestDefaultConstructor) {
     using X = variant<NonNoexceptDefaultConstructible>;
     X x{};
     ASSERT_FALSE(x.valueless_by_exception());
-    ASSERT_EQ(0, x.index());
+    ASSERT_EQ(0u, x.index());
     EXPECT_EQ(5, absl::get<0>(x).value);
     EXPECT_FALSE(std::is_nothrow_default_constructible<X>::value);
   }
@@ -299,7 +299,7 @@ TEST(VariantTest, TestDefaultConstructor) {
     using X = variant<int, NonNoexceptDefaultConstructible>;
     X x{};
     ASSERT_FALSE(x.valueless_by_exception());
-    ASSERT_EQ(0, x.index());
+    ASSERT_EQ(0u, x.index());
     EXPECT_EQ(0, absl::get<0>(x));
     EXPECT_TRUE(std::is_nothrow_default_constructible<X>::value);
   }
@@ -308,7 +308,7 @@ TEST(VariantTest, TestDefaultConstructor) {
     using X = variant<NonNoexceptDefaultConstructible, int>;
     X x{};
     ASSERT_FALSE(x.valueless_by_exception());
-    ASSERT_EQ(0, x.index());
+    ASSERT_EQ(0u, x.index());
     EXPECT_EQ(5, absl::get<0>(x).value);
     EXPECT_FALSE(std::is_nothrow_default_constructible<X>::value);
   }
@@ -480,7 +480,7 @@ TEST(VariantTest, InPlaceType) {
   ASSERT_TRUE(absl::holds_alternative<std::string>(v2));
   EXPECT_EQ("ABC", absl::get<std::string>(v2));
 
-  Var v3(in_place_type_t<std::string>(), "ABC", 2);
+  Var v3(in_place_type_t<std::string>(), "ABC", 2u);
   ASSERT_TRUE(absl::holds_alternative<std::string>(v3));
   EXPECT_EQ("AB", absl::get<std::string>(v3));
 
@@ -503,7 +503,7 @@ TEST(VariantTest, InPlaceTypeVariableTemplate) {
   ASSERT_TRUE(absl::holds_alternative<std::string>(v2));
   EXPECT_EQ("ABC", absl::get<std::string>(v2));
 
-  Var v3(in_place_type<std::string>, "ABC", 2);
+  Var v3(in_place_type<std::string>, "ABC", 2u);
   ASSERT_TRUE(absl::holds_alternative<std::string>(v3));
   EXPECT_EQ("AB", absl::get<std::string>(v3));
 
@@ -544,7 +544,7 @@ TEST(VariantTest, InPlaceIndex) {
   ASSERT_TRUE(absl::holds_alternative<std::string>(v2));
   EXPECT_EQ("ABC", absl::get<std::string>(v2));
 
-  Var v3(in_place_index_t<1>(), "ABC", 2);
+  Var v3(in_place_index_t<1>(), "ABC", 2u);
   ASSERT_TRUE(absl::holds_alternative<std::string>(v3));
   EXPECT_EQ("AB", absl::get<std::string>(v3));
 
@@ -571,7 +571,7 @@ TEST(VariantTest, InPlaceIndexVariableTemplate) {
   ASSERT_TRUE(absl::holds_alternative<std::string>(v2));
   EXPECT_EQ("ABC", absl::get<std::string>(v2));
 
-  Var v3(in_place_index<1>, "ABC", 2);
+  Var v3(in_place_index<1>, "ABC", 2u);
   ASSERT_TRUE(absl::holds_alternative<std::string>(v3));
   EXPECT_EQ("AB", absl::get<std::string>(v3));
 
@@ -688,11 +688,11 @@ TEST(VariantTest, TestSelfAssignment) {
   EXPECT_EQ(long_str, foo);
 
   variant<int, std::string> so = long_str;
-  ASSERT_EQ(1, so.index());
+  ASSERT_EQ(1u, so.index());
   EXPECT_EQ(long_str, absl::get<1>(so));
   so = *&so;
 
-  ASSERT_EQ(1, so.index());
+  ASSERT_EQ(1u, so.index());
   EXPECT_EQ(long_str, absl::get<1>(so));
 }
 
@@ -968,16 +968,16 @@ TEST(VariantTest, Index) {
   using Var = variant<int, std::string, double>;
 
   Var v = 1;
-  EXPECT_EQ(0, v.index());
+  EXPECT_EQ(0u, v.index());
   v = "str";
-  EXPECT_EQ(1, v.index());
+  EXPECT_EQ(1u, v.index());
   v = 0.;
-  EXPECT_EQ(2, v.index());
+  EXPECT_EQ(2u, v.index());
 
   Var v2 = v;
-  EXPECT_EQ(2, v2.index());
+  EXPECT_EQ(2u, v2.index());
   v2.emplace<int>(3);
-  EXPECT_EQ(0, v2.index());
+  EXPECT_EQ(0u, v2.index());
 }
 
 TEST(VariantTest, NotValuelessByException) {
@@ -1002,11 +1002,11 @@ TEST(VariantTest, IndexValuelessByException) {
   using Var = variant<MoveCanThrow, std::string, double>;
 
   Var v(absl::in_place_index<0>);
-  EXPECT_EQ(0, v.index());
+  EXPECT_EQ(0u, v.index());
   ToValuelessByException(v);
   EXPECT_EQ(absl::variant_npos, v.index());
   v = "str";
-  EXPECT_EQ(1, v.index());
+  EXPECT_EQ(1u, v.index());
 }
 
 TEST(VariantTest, ValuelessByException) {
@@ -1084,18 +1084,18 @@ TEST(VariantTest, MemberSwap) {
 TEST(VariantTest, VariantSize) {
   {
     using Size1Variant = absl::variant<int>;
-    EXPECT_EQ(1, absl::variant_size<Size1Variant>::value);
-    EXPECT_EQ(1, absl::variant_size<const Size1Variant>::value);
-    EXPECT_EQ(1, absl::variant_size<volatile Size1Variant>::value);
-    EXPECT_EQ(1, absl::variant_size<const volatile Size1Variant>::value);
+    EXPECT_EQ(1u, absl::variant_size<Size1Variant>::value);
+    EXPECT_EQ(1u, absl::variant_size<const Size1Variant>::value);
+    EXPECT_EQ(1u, absl::variant_size<volatile Size1Variant>::value);
+    EXPECT_EQ(1u, absl::variant_size<const volatile Size1Variant>::value);
   }
 
   {
     using Size3Variant = absl::variant<int, float, int>;
-    EXPECT_EQ(3, absl::variant_size<Size3Variant>::value);
-    EXPECT_EQ(3, absl::variant_size<const Size3Variant>::value);
-    EXPECT_EQ(3, absl::variant_size<volatile Size3Variant>::value);
-    EXPECT_EQ(3, absl::variant_size<const volatile Size3Variant>::value);
+    EXPECT_EQ(3u, absl::variant_size<Size3Variant>::value);
+    EXPECT_EQ(3u, absl::variant_size<const Size3Variant>::value);
+    EXPECT_EQ(3u, absl::variant_size<volatile Size3Variant>::value);
+    EXPECT_EQ(3u, absl::variant_size<const volatile Size3Variant>::value);
   }
 }
 
@@ -1799,14 +1799,14 @@ TEST(VariantTest, VisitSimple) {
   EXPECT_EQ("B", piece);
 
   struct StrLen {
-    int operator()(const char* s) const { return strlen(s); }
-    int operator()(const std::string& s) const { return s.size(); }
+    size_t operator()(const char* s) const { return strlen(s); }
+    size_t operator()(const std::string& s) const { return s.size(); }
   };
 
   v = "SomeStr";
-  EXPECT_EQ(7, absl::visit(StrLen{}, v));
+  EXPECT_EQ(7u, absl::visit(StrLen{}, v));
   v = std::string("VeryLargeThisTime");
-  EXPECT_EQ(17, absl::visit(StrLen{}, v));
+  EXPECT_EQ(17u, absl::visit(StrLen{}, v));
 }
 
 TEST(VariantTest, VisitRValue) {
@@ -1979,7 +1979,7 @@ TEST(VariantTest, MonostateBasic) {
 
 TEST(VariantTest, VariantMonostateDefaultConstruction) {
   absl::variant<absl::monostate, NonDefaultConstructible> var;
-  EXPECT_EQ(var.index(), 0);
+  EXPECT_EQ(var.index(), 0u);
 }
 
 ////////////////////////////////
@@ -2100,7 +2100,7 @@ TEST(VariantTest, Hash) {
     for (int i = 0; i < 100; ++i) {
       hashcodes.insert(hash(i));
     }
-    EXPECT_GT(hashcodes.size(), 90);
+    EXPECT_GT(hashcodes.size(), 90u);
 
     // test const-qualified
     static_assert(type_traits_internal::IsHashable<variant<const int>>::value,
@@ -2312,9 +2312,9 @@ TEST(VariantTest, TestRvalueConversion) {
   EXPECT_EQ(42, absl::get<int32_t>(variant2));
 
   variant2 =
-      ConvertVariantTo<variant<int32_t, uint32_t>>(variant<uint32_t>(42));
+      ConvertVariantTo<variant<int32_t, uint32_t>>(variant<uint32_t>(42u));
   ASSERT_TRUE(absl::holds_alternative<uint32_t>(variant2));
-  EXPECT_EQ(42, absl::get<uint32_t>(variant2));
+  EXPECT_EQ(42u, absl::get<uint32_t>(variant2));
 #endif  // !ABSL_USES_STD_VARIANT
 
   variant<Convertible1, Convertible2> variant3(
@@ -2361,10 +2361,10 @@ TEST(VariantTest, TestLvalueConversion) {
   ASSERT_TRUE(absl::holds_alternative<int32_t>(variant2));
   EXPECT_EQ(42, absl::get<int32_t>(variant2));
 
-  variant<uint32_t> source6(42);
+  variant<uint32_t> source6(42u);
   variant2 = ConvertVariantTo<variant<int32_t, uint32_t>>(source6);
   ASSERT_TRUE(absl::holds_alternative<uint32_t>(variant2));
-  EXPECT_EQ(42, absl::get<uint32_t>(variant2));
+  EXPECT_EQ(42u, absl::get<uint32_t>(variant2));
 #endif
 
   variant<Convertible2, Convertible1> source7((Convertible1()));
@@ -2455,8 +2455,8 @@ TEST(VariantTest, TestRvalueConversionViaConvertVariantTo) {
   EXPECT_THAT(absl::get_if<int32_t>(&variant2), Pointee(42));
 
   variant2 =
-      ConvertVariantTo<variant<int32_t, uint32_t>>(variant<uint32_t>(42));
-  EXPECT_THAT(absl::get_if<uint32_t>(&variant2), Pointee(42));
+      ConvertVariantTo<variant<int32_t, uint32_t>>(variant<uint32_t>(42u));
+  EXPECT_THAT(absl::get_if<uint32_t>(&variant2), Pointee(42u));
 #endif
 
   variant<Convertible1, Convertible2> variant3(
@@ -2499,9 +2499,9 @@ TEST(VariantTest, TestLvalueConversionViaConvertVariantTo) {
       ConvertVariantTo<variant<int32_t, uint32_t>>(source5));
   EXPECT_THAT(absl::get_if<int32_t>(&variant2), Pointee(42));
 
-  variant<uint32_t> source6(42);
+  variant<uint32_t> source6(42u);
   variant2 = ConvertVariantTo<variant<int32_t, uint32_t>>(source6);
-  EXPECT_THAT(absl::get_if<uint32_t>(&variant2), Pointee(42));
+  EXPECT_THAT(absl::get_if<uint32_t>(&variant2), Pointee(42u));
 #endif  // !ABSL_USES_STD_VARIANT
 
   variant<Convertible2, Convertible1> source7((Convertible1()));
@@ -2570,7 +2570,7 @@ TEST(VariantTest, TestVectorOfMoveonlyVariant) {
   vec.reserve(3);
   auto another_vec = absl::move(vec);
   // As a sanity check, verify vector contents.
-  ASSERT_EQ(2, another_vec.size());
+  ASSERT_EQ(2u, another_vec.size());
   EXPECT_EQ(42, *absl::get<std::unique_ptr<int>>(another_vec[0]));
   EXPECT_EQ("Hello", absl::get<std::string>(another_vec[1]));
 }