diff --git a/libc/test/src/stdlib/strtol_test.cpp b/libc/test/src/stdlib/strtol_test.cpp
--- a/libc/test/src/stdlib/strtol_test.cpp
+++ b/libc/test/src/stdlib/strtol_test.cpp
@@ -149,19 +149,19 @@
   if (input < 0 || input > 36)
     return '0';
   if (input < 10)
-    return '0' + input;
-  return 'A' + input - 10;
+    return static_cast<char>('0' + input);
+  return static_cast<char>('A' + input - 10);
 }
 
 TEST(LlvmLibcStrToLTest, DecodeInOtherBases) {
   char small_string[4] = {'\0', '\0', '\0', '\0'};
-  for (long base = 2; base <= 36; ++base) {
-    for (long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
       if (first_digit < base) {
         errno = 0;
         ASSERT_EQ(__llvm_libc::strtol(small_string, nullptr, base),
-                  first_digit);
+                  static_cast<long int>(first_digit));
         ASSERT_EQ(errno, 0);
       } else {
         errno = 0;
@@ -171,20 +171,20 @@
     }
   }
 
-  for (long base = 2; base <= 36; ++base) {
-    for (long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (long second_digit = 0; second_digit <= 36; ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
         if (first_digit < base && second_digit < base) {
           errno = 0;
           ASSERT_EQ(__llvm_libc::strtol(small_string, nullptr, base),
-                    second_digit + (first_digit * base));
+                    static_cast<long int>(second_digit + (first_digit * base)));
           ASSERT_EQ(errno, 0);
         } else if (first_digit < base) {
           errno = 0;
           ASSERT_EQ(__llvm_libc::strtol(small_string, nullptr, base),
-                    first_digit);
+                    static_cast<long int>(first_digit));
           ASSERT_EQ(errno, 0);
         } else {
           errno = 0;
@@ -195,24 +195,26 @@
     }
   }
 
-  for (long base = 2; base <= 36; ++base) {
-    for (long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (long second_digit = 0; second_digit <= 36; ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
-        for (long third_digit = 0; third_digit <= 36; ++third_digit) {
+        for (int third_digit = 0; third_digit <= 36; ++third_digit) {
           small_string[2] = int_to_b36_char(third_digit);
 
           if (first_digit < base && second_digit < base && third_digit < base) {
             errno = 0;
             ASSERT_EQ(__llvm_libc::strtol(small_string, nullptr, base),
-                      third_digit + (second_digit * base) +
-                          (first_digit * base * base));
+                      static_cast<long int>(third_digit +
+                                            (second_digit * base) +
+                                            (first_digit * base * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base && second_digit < base) {
             errno = 0;
-            ASSERT_EQ(__llvm_libc::strtol(small_string, nullptr, base),
-                      second_digit + (first_digit * base));
+            ASSERT_EQ(
+                __llvm_libc::strtol(small_string, nullptr, base),
+                static_cast<long int>(second_digit + (first_digit * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base) {
             // if the base is 16 there is a special case for the prefix 0X.
@@ -221,7 +223,7 @@
               if (third_digit < base) {
                 errno = 0;
                 ASSERT_EQ(__llvm_libc::strtol(small_string, nullptr, base),
-                          third_digit);
+                          static_cast<long int>(third_digit));
                 ASSERT_EQ(errno, 0);
               } else {
                 errno = 0;
@@ -231,7 +233,7 @@
             } else {
               errno = 0;
               ASSERT_EQ(__llvm_libc::strtol(small_string, nullptr, base),
-                        first_digit);
+                        static_cast<long int>(first_digit));
               ASSERT_EQ(errno, 0);
             }
           } else {
diff --git a/libc/test/src/stdlib/strtoll_test.cpp b/libc/test/src/stdlib/strtoll_test.cpp
--- a/libc/test/src/stdlib/strtoll_test.cpp
+++ b/libc/test/src/stdlib/strtoll_test.cpp
@@ -173,19 +173,19 @@
   if (input < 0 || input > 36)
     return '0';
   if (input < 10)
-    return '0' + input;
-  return 'A' + input - 10;
+    return static_cast<char>('0' + input);
+  return static_cast<char>('A' + input - 10);
 }
 
 TEST(LlvmLibcStrToLLTest, DecodeInOtherBases) {
   char small_string[4] = {'\0', '\0', '\0', '\0'};
-  for (long long base = 2; base <= 36; ++base) {
-    for (long long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
       if (first_digit < base) {
         errno = 0;
         ASSERT_EQ(__llvm_libc::strtoll(small_string, nullptr, base),
-                  first_digit);
+                  static_cast<long long int>(first_digit));
         ASSERT_EQ(errno, 0);
       } else {
         errno = 0;
@@ -195,20 +195,21 @@
     }
   }
 
-  for (long long base = 2; base <= 36; ++base) {
-    for (long long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (long long second_digit = 0; second_digit <= 36; ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
         if (first_digit < base && second_digit < base) {
           errno = 0;
-          ASSERT_EQ(__llvm_libc::strtoll(small_string, nullptr, base),
-                    second_digit + (first_digit * base));
+          ASSERT_EQ(
+              __llvm_libc::strtoll(small_string, nullptr, base),
+              static_cast<long long int>(second_digit + (first_digit * base)));
           ASSERT_EQ(errno, 0);
         } else if (first_digit < base) {
           errno = 0;
           ASSERT_EQ(__llvm_libc::strtoll(small_string, nullptr, base),
-                    first_digit);
+                    static_cast<long long int>(first_digit));
           ASSERT_EQ(errno, 0);
         } else {
           errno = 0;
@@ -219,24 +220,26 @@
     }
   }
 
-  for (long long base = 2; base <= 36; ++base) {
-    for (long long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (long long second_digit = 0; second_digit <= 36; ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
-        for (long long third_digit = 0; third_digit <= 36; ++third_digit) {
+        for (int third_digit = 0; third_digit <= 36; ++third_digit) {
           small_string[2] = int_to_b36_char(third_digit);
 
           if (first_digit < base && second_digit < base && third_digit < base) {
             errno = 0;
             ASSERT_EQ(__llvm_libc::strtoll(small_string, nullptr, base),
-                      third_digit + (second_digit * base) +
-                          (first_digit * base * base));
+                      static_cast<long long int>(third_digit +
+                                                 (second_digit * base) +
+                                                 (first_digit * base * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base && second_digit < base) {
             errno = 0;
             ASSERT_EQ(__llvm_libc::strtoll(small_string, nullptr, base),
-                      second_digit + (first_digit * base));
+                      static_cast<long long int>(second_digit +
+                                                 (first_digit * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base) {
             // if the base is 16 there is a special case for the prefix 0X.
@@ -245,7 +248,7 @@
               if (third_digit < base) {
                 errno = 0;
                 ASSERT_EQ(__llvm_libc::strtoll(small_string, nullptr, base),
-                          third_digit);
+                          static_cast<long long int>(third_digit));
                 ASSERT_EQ(errno, 0);
               } else {
                 errno = 0;
@@ -256,7 +259,7 @@
             } else {
               errno = 0;
               ASSERT_EQ(__llvm_libc::strtoll(small_string, nullptr, base),
-                        first_digit);
+                        static_cast<long long int>(first_digit));
               ASSERT_EQ(errno, 0);
             }
           } else {
diff --git a/libc/test/src/stdlib/strtoul_test.cpp b/libc/test/src/stdlib/strtoul_test.cpp
--- a/libc/test/src/stdlib/strtoul_test.cpp
+++ b/libc/test/src/stdlib/strtoul_test.cpp
@@ -8,12 +8,12 @@
 
 #include "src/stdlib/strtoul.h"
 
-#include "utils/UnitTest/Test.h"
-
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>
 
+#include "utils/UnitTest/Test.h"
+
 TEST(LlvmLibcStrToULTest, InvalidBase) {
   const char *ten = "10";
   errno = 0;
@@ -141,19 +141,19 @@
   if (input < 0 || input > 36)
     return '0';
   if (input < 10)
-    return '0' + input;
-  return 'A' + input - 10;
+    return static_cast<char>('0' + input);
+  return static_cast<char>('A' + input - 10);
 }
 
 TEST(LlvmLibcStrToULTest, DecodeInOtherBases) {
   char small_string[4] = {'\0', '\0', '\0', '\0'};
-  for (unsigned long base = 2; base <= 36; ++base) {
-    for (unsigned long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
       if (first_digit < base) {
         errno = 0;
         ASSERT_EQ(__llvm_libc::strtoul(small_string, nullptr, base),
-                  first_digit);
+                  static_cast<unsigned long int>(first_digit));
         ASSERT_EQ(errno, 0);
       } else {
         errno = 0;
@@ -163,20 +163,21 @@
     }
   }
 
-  for (unsigned long base = 2; base <= 36; ++base) {
-    for (unsigned long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (unsigned long second_digit = 0; second_digit <= 36; ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
         if (first_digit < base && second_digit < base) {
           errno = 0;
           ASSERT_EQ(__llvm_libc::strtoul(small_string, nullptr, base),
-                    second_digit + (first_digit * base));
+                    static_cast<unsigned long int>(second_digit +
+                                                   (first_digit * base)));
           ASSERT_EQ(errno, 0);
         } else if (first_digit < base) {
           errno = 0;
           ASSERT_EQ(__llvm_libc::strtoul(small_string, nullptr, base),
-                    first_digit);
+                    static_cast<unsigned long int>(first_digit));
           ASSERT_EQ(errno, 0);
         } else {
           errno = 0;
@@ -187,24 +188,26 @@
     }
   }
 
-  for (unsigned long base = 2; base <= 36; ++base) {
-    for (unsigned long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (unsigned long second_digit = 0; second_digit <= 36; ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
-        for (unsigned long third_digit = 0; third_digit <= 36; ++third_digit) {
+        for (int third_digit = 0; third_digit <= 36; ++third_digit) {
           small_string[2] = int_to_b36_char(third_digit);
 
           if (first_digit < base && second_digit < base && third_digit < base) {
             errno = 0;
             ASSERT_EQ(__llvm_libc::strtoul(small_string, nullptr, base),
-                      third_digit + (second_digit * base) +
-                          (first_digit * base * base));
+                      static_cast<unsigned long int>(
+                          third_digit + (second_digit * base) +
+                          (first_digit * base * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base && second_digit < base) {
             errno = 0;
             ASSERT_EQ(__llvm_libc::strtoul(small_string, nullptr, base),
-                      second_digit + (first_digit * base));
+                      static_cast<unsigned long int>(second_digit +
+                                                     (first_digit * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base) {
             // if the base is 16 there is a special case for the prefix 0X.
@@ -213,7 +216,7 @@
               if (third_digit < base) {
                 errno = 0;
                 ASSERT_EQ(__llvm_libc::strtoul(small_string, nullptr, base),
-                          third_digit);
+                          static_cast<unsigned long int>(third_digit));
                 ASSERT_EQ(errno, 0);
               } else {
                 errno = 0;
diff --git a/libc/test/src/stdlib/strtoull_test.cpp b/libc/test/src/stdlib/strtoull_test.cpp
--- a/libc/test/src/stdlib/strtoull_test.cpp
+++ b/libc/test/src/stdlib/strtoull_test.cpp
@@ -8,12 +8,12 @@
 
 #include "src/stdlib/strtoull.h"
 
-#include "utils/UnitTest/Test.h"
-
 #include <errno.h>
 #include <limits.h>
 #include <stddef.h>
 
+#include "utils/UnitTest/Test.h"
+
 TEST(LlvmLibcStrToULLTest, InvalidBase) {
   const char *ten = "10";
   errno = 0;
@@ -149,19 +149,19 @@
   if (input < 0 || input > 36)
     return '0';
   if (input < 10)
-    return '0' + input;
-  return 'A' + input - 10;
+    return static_cast<char>('0' + input);
+  return static_cast<char>('A' + input - 10);
 }
 
 TEST(LlvmLibcStrToULLTest, DecodeInOtherBases) {
   char small_string[4] = {'\0', '\0', '\0', '\0'};
-  for (unsigned long long base = 2; base <= 36; ++base) {
-    for (unsigned long long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
       if (first_digit < base) {
         errno = 0;
         ASSERT_EQ(__llvm_libc::strtoull(small_string, nullptr, base),
-                  first_digit);
+                  static_cast<unsigned long long int>(first_digit));
         ASSERT_EQ(errno, 0);
       } else {
         errno = 0;
@@ -171,21 +171,21 @@
     }
   }
 
-  for (unsigned long long base = 2; base <= 36; ++base) {
-    for (unsigned long long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (unsigned long long second_digit = 0; second_digit <= 36;
-           ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
         if (first_digit < base && second_digit < base) {
           errno = 0;
           ASSERT_EQ(__llvm_libc::strtoull(small_string, nullptr, base),
-                    second_digit + (first_digit * base));
+                    static_cast<unsigned long long int>(second_digit +
+                                                        (first_digit * base)));
           ASSERT_EQ(errno, 0);
         } else if (first_digit < base) {
           errno = 0;
           ASSERT_EQ(__llvm_libc::strtoull(small_string, nullptr, base),
-                    first_digit);
+                    static_cast<unsigned long long int>(first_digit));
           ASSERT_EQ(errno, 0);
         } else {
           errno = 0;
@@ -196,26 +196,26 @@
     }
   }
 
-  for (unsigned long long base = 2; base <= 36; ++base) {
-    for (unsigned long long first_digit = 0; first_digit <= 36; ++first_digit) {
+  for (int base = 2; base <= 36; ++base) {
+    for (int first_digit = 0; first_digit <= 36; ++first_digit) {
       small_string[0] = int_to_b36_char(first_digit);
-      for (unsigned long long second_digit = 0; second_digit <= 36;
-           ++second_digit) {
+      for (int second_digit = 0; second_digit <= 36; ++second_digit) {
         small_string[1] = int_to_b36_char(second_digit);
-        for (unsigned long long third_digit = 0; third_digit <= 36;
-             ++third_digit) {
+        for (int third_digit = 0; third_digit <= 36; ++third_digit) {
           small_string[2] = int_to_b36_char(third_digit);
 
           if (first_digit < base && second_digit < base && third_digit < base) {
             errno = 0;
             ASSERT_EQ(__llvm_libc::strtoull(small_string, nullptr, base),
-                      third_digit + (second_digit * base) +
-                          (first_digit * base * base));
+                      static_cast<unsigned long long int>(
+                          third_digit + (second_digit * base) +
+                          (first_digit * base * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base && second_digit < base) {
             errno = 0;
             ASSERT_EQ(__llvm_libc::strtoull(small_string, nullptr, base),
-                      second_digit + (first_digit * base));
+                      static_cast<unsigned long long int>(
+                          second_digit + (first_digit * base)));
             ASSERT_EQ(errno, 0);
           } else if (first_digit < base) {
             // if the base is 16 there is a special case for the prefix 0X.
@@ -224,7 +224,7 @@
               if (third_digit < base) {
                 errno = 0;
                 ASSERT_EQ(__llvm_libc::strtoull(small_string, nullptr, base),
-                          third_digit);
+                          static_cast<unsigned long long int>(third_digit));
                 ASSERT_EQ(errno, 0);
               } else {
                 errno = 0;
@@ -235,7 +235,7 @@
             } else {
               errno = 0;
               ASSERT_EQ(__llvm_libc::strtoull(small_string, nullptr, base),
-                        first_digit);
+                        static_cast<unsigned long long int>(first_digit));
               ASSERT_EQ(errno, 0);
             }
           } else {