diff --git a/src/builtins.c b/src/builtins.c
index 7734698..ddd46f9 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -5,8 +5,8 @@
 #include "util.h"
 #include "debug.h"
 
-KrkClass * Helper;
-KrkClass * LicenseReader;
+static KrkClass * Helper;
+static KrkClass * LicenseReader;
 
 KrkValue krk_dirObject(int argc, KrkValue argv[], int hasKw) {
 	if (argc != 1) return krk_runtimeError(vm.exceptions->argumentError, "wrong number of arguments or bad type, got %d\n", argc);
diff --git a/src/obj_base.c b/src/obj_base.c
index 0c97240..7c9dfdf 100644
--- a/src/obj_base.c
+++ b/src/obj_base.c
@@ -59,6 +59,7 @@ static KrkValue _class_to_str(int argc, KrkValue argv[], int hasKw) {
 	return OBJECT_VAL(out);
 }
 
+_noexport
 void _createAndBind_type(void) {
 	ADD_BASE_CLASS(vm.baseClasses->typeClass, "type", vm.baseClasses->objectClass);
 	krk_defineNative(&vm.baseClasses->typeClass->methods, ":__base__", krk_baseOfClass);
diff --git a/src/os.c b/src/os.c
index 6bed6b4..38a145b 100644
--- a/src/os.c
+++ b/src/os.c
@@ -21,8 +21,8 @@
 /* Did you know this is actually specified to not exist in a header? */
 extern char ** environ;
 
-KrkClass * OSError = NULL;
-KrkClass * stat_result = NULL;
+static KrkClass * OSError = NULL;
+static KrkClass * stat_result = NULL;
 
 #define DO_KEY(key) krk_attachNamedObject(AS_DICT(result), #key, (KrkObj*)krk_copyString(buf. key, strlen(buf .key)))
 #define S_KEY(key,val) krk_attachNamedObject(AS_DICT(result), #key, (KrkObj*)val);
@@ -89,7 +89,7 @@ KRK_FUNC(uname,{
 })
 #endif
 
-KrkClass * environClass;
+static KrkClass * environClass;
 
 KrkValue krk_os_setenviron(int argc, KrkValue argv[], int hasKw) {
 	if (argc < 3 || !krk_isInstanceOf(argv[0], environClass) ||
diff --git a/src/threads.c b/src/threads.c
index 3eea1e8..368241d 100644
--- a/src/threads.c
+++ b/src/threads.c
@@ -17,8 +17,9 @@
 #define gettid() -1
 #endif
 
-KrkClass * ThreadError;
-KrkClass * Thread;
+static KrkClass * ThreadError;
+static KrkClass * Thread;
+
 /**
  * @brief Object representation of a system thread.
  * @extends KrkInstance
@@ -38,7 +39,8 @@ struct Thread {
 	unsigned int    alive:1;
 };
 
-KrkClass * Lock;
+static KrkClass * Lock;
+
 /**
  * @brief Simple atomic structure for waiting.
  * @extends KrkInstance
@@ -192,8 +194,6 @@ KRK_METHOD(Lock,__exit__,{
 	pthread_mutex_unlock(&self->mutex);
 })
 
-KrkInstance * threadsModule;
-
 _noexport
 void _createAndBind_threadsMod(void) {
 	/**
@@ -201,7 +201,7 @@ void _createAndBind_threadsMod(void) {
 	 *
 	 * Methods for dealing with threads.
 	 */
-	threadsModule = krk_newInstance(vm.baseClasses->moduleClass);
+	KrkInstance * threadsModule = krk_newInstance(vm.baseClasses->moduleClass);
 
 	krk_attachNamedObject(&vm.modules, "threading", (KrkObj*)threadsModule);
 	krk_attachNamedObject(&threadsModule->fields, "__name__", (KrkObj*)S("threading"));
diff --git a/test/day5.krk b/test/day5.krk
index 34d700e..7e971d7 100644
--- a/test/day5.krk
+++ b/test/day5.krk
@@ -49,26 +49,6 @@ for l in lines:
     let i = seat_id(l)
     taken[i] = 1
 
-def min(iter):
-    let l # Silly way to get the first value of an iterable that doesn't do []
-    for v in iter:
-        l = v
-        break
-    for v in iter:
-        if v < l:
-            l = v
-    return l
-
-def max(iter):
-    let l # Silly way to get the first value of an iterable that doesn't do []
-    for v in iter:
-        l = v
-        break
-    for v in iter:
-        if v > l:
-            l = v
-    return l
-
 print("---")
 for i in range(min(taken.keys()), max(taken.keys())):
     if (i - 1) in taken and (i + 1) in taken and i not in taken:
diff --git a/test/testGeneratorExpressions.krk b/test/testGeneratorExpressions.krk
index 3ce1b7e..1124171 100644
--- a/test/testGeneratorExpressions.krk
+++ b/test/testGeneratorExpressions.krk
@@ -1,21 +1,15 @@
-def _sum(iterable):
-    let total = 0
-    for i in iterable:
-        total += i
-    return total
-
-print(_sum([x * x for x in range(10)]))
-print(_sum((x * x for x in range(10))))
+print(sum([x * x for x in range(10)]))
+print(sum((x * x for x in range(10))))
 
 print('generator object' in str((x * x for x in range(10))))
 
 # Should be directly usable as function argument
-print(_sum(x * x for x in range(10)))
+print(sum(x * x for x in range(10)))
 
 import dis
 # Should have a compile error:
 try:
-    dis.build('_sum(x * x for x in range(10), 2, 3)')
+    dis.build('sum(x * x for x in range(10), 2, 3)')
 except SyntaxError as e:
     print('parenthesized' in str(e))