diff --git a/absl/base/internal/strerror.cc b/absl/base/internal/strerror.cc
index d66ba120..0d6226fd 100644
--- a/absl/base/internal/strerror.cc
+++ b/absl/base/internal/strerror.cc
@@ -51,7 +51,6 @@ const char* StrErrorAdaptor(int errnum, char* buf, size_t buflen) {
 }
 
 std::string StrErrorInternal(int errnum) {
-  absl::base_internal::ErrnoSaver errno_saver;
   char buf[100];
   const char* str = StrErrorAdaptor(errnum, buf, sizeof buf);
   if (*str == '\0') {
@@ -76,6 +75,7 @@ std::array<std::string, kSysNerr>* NewStrErrorTable() {
 }  // namespace
 
 std::string StrError(int errnum) {
+  absl::base_internal::ErrnoSaver errno_saver;
   static const auto* table = NewStrErrorTable();
   if (errnum >= 0 && errnum < static_cast<int>(table->size())) {
     return (*table)[errnum];
diff --git a/absl/base/internal/strerror_test.cc b/absl/base/internal/strerror_test.cc
index a53da97f..e32d5b5c 100644
--- a/absl/base/internal/strerror_test.cc
+++ b/absl/base/internal/strerror_test.cc
@@ -62,12 +62,14 @@ TEST(StrErrorTest, MultipleThreads) {
       ++counter;
       errno = ERANGE;
       const std::string value = absl::base_internal::StrError(i);
+      // EXPECT_* could change errno. Stash it first.
+      int check_err = errno;
+      EXPECT_THAT(check_err, Eq(ERANGE));
       // Only the GNU implementation is guaranteed to provide the
       // string "Unknown error nnn". POSIX doesn't say anything.
       if (!absl::StartsWith(value, "Unknown error ")) {
-        EXPECT_THAT(absl::base_internal::StrError(i), Eq(expected_strings[i]));
+        EXPECT_THAT(value, Eq(expected_strings[i]));
       }
-      EXPECT_THAT(errno, Eq(ERANGE));
     }
   };
 
diff --git a/absl/base/optimization.h b/absl/base/optimization.h
index 393fc3a4..57b4dccf 100644
--- a/absl/base/optimization.h
+++ b/absl/base/optimization.h
@@ -22,6 +22,8 @@
 #ifndef ABSL_BASE_OPTIMIZATION_H_
 #define ABSL_BASE_OPTIMIZATION_H_
 
+#include <assert.h>
+
 #include "absl/base/config.h"
 
 // ABSL_BLOCK_TAIL_CALL_OPTIMIZATION
@@ -216,7 +218,7 @@
 // This macro forces small unique name on a static file level symbols like
 // static local variables or static functions. This is intended to be used in
 // macro definitions to optimize the cost of generated code. Do NOT use it on
-// symbols exported from translation unit since it may casue a link time
+// symbols exported from translation unit since it may cause a link time
 // conflict.
 //
 // Example:
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index 4477f7dc..74b2ef4c 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -189,7 +189,7 @@ constexpr bool IsNoThrowSwappable(std::false_type /* is_swappable */) {
 }
 
 template <typename T>
-int TrailingZeros(T x) {
+uint32_t TrailingZeros(T x) {
   ABSL_INTERNAL_ASSUME(x != 0);
   return countr_zero(x);
 }
@@ -221,19 +221,21 @@ class BitMask {
   }
   explicit operator bool() const { return mask_ != 0; }
   int operator*() const { return LowestBitSet(); }
-  int LowestBitSet() const {
+  uint32_t LowestBitSet() const {
     return container_internal::TrailingZeros(mask_) >> Shift;
   }
-  int HighestBitSet() const { return (bit_width(mask_) - 1) >> Shift; }
+  uint32_t HighestBitSet() const {
+    return static_cast<uint32_t>((bit_width(mask_) - 1) >> Shift);
+  }
 
   BitMask begin() const { return *this; }
   BitMask end() const { return BitMask(0); }
 
-  int TrailingZeros() const {
+  uint32_t TrailingZeros() const {
     return container_internal::TrailingZeros(mask_) >> Shift;
   }
 
-  int LeadingZeros() const {
+  uint32_t LeadingZeros() const {
     constexpr int total_significant_bits = SignificantBits << Shift;
     constexpr int extra_bits = sizeof(T) * 8 - total_significant_bits;
     return countl_zero(mask_ << extra_bits) >> Shift;