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
@@ -149,14 +149,14 @@
   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;
@@ -171,10 +171,10 @@
     }
   }
 
-  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;
@@ -195,12 +195,12 @@
     }
   }
 
-  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) {
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
@@ -173,14 +173,14 @@
   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;
@@ -195,10 +195,10 @@
     }
   }
 
-  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;
@@ -219,12 +219,12 @@
     }
   }
 
-  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) {
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;
@@ -141,14 +141,14 @@
   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;
@@ -163,10 +163,10 @@
     }
   }
 
-  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;
@@ -187,12 +187,12 @@
     }
   }
 
-  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) {
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;
@@ -149,14 +149,14 @@
   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;
@@ -171,11 +171,10 @@
     }
   }
 
-  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;
@@ -196,14 +195,12 @@
     }
   }
 
-  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) {