diff --git a/lib/std/core/string.c3 b/lib/std/core/string.c3
index b1d417fda..dc84186c5 100644
--- a/lib/std/core/string.c3
+++ b/lib/std/core/string.c3
@@ -43,8 +43,9 @@ fn String new(char[] c)
 
 fn ZString String.zstr(String* str)
 {
-	StringData* data = str.data();
 	if (!str) return (ZString)"";
+	StringData* data = str.data();
+	if (!data) return (ZString)"";
 	if (data.capacity == data.len)
 	{
 		libc::printf("feofk\n");
@@ -63,6 +64,7 @@ fn usize String.len(String* this)
 	if (!*this) return 0;
 	return this.data().len;
 }
+
 /**
  * @require new_size <= this.len()
  */
@@ -87,6 +89,25 @@ fn void String.append_utf32(String* str, Char32[] chars)
 	}
 }
 
+/**
+ * @require index < str.len()
+ **/
+fn void String.set(String* str, usize index, char c)
+{
+	str.data().chars[index] = c;
+}
+
+fn void String.append_repeat(String* str, char c, usize times)
+{
+	if (times == 0) return;
+	str.reserve(times);
+	StringData* data = str.data();
+	for (usize i = 0; i < times; i++)
+	{
+        data.chars[data.len++] = c;
+	}
+}
+
 /**
  * @require c < 0x10ffff
  */
@@ -174,6 +195,7 @@ fn void String.destroy(String* str)
 {
 	if (!*str) return;
 	StringData* data = str.data();
+	if (!data) return;
 	data.allocator.free(data);
 	*str = (String)null;
 }
diff --git a/resources/examples/binarydigits.c3 b/resources/examples/binarydigits.c3
new file mode 100644
index 000000000..3b3fd415d
--- /dev/null
+++ b/resources/examples/binarydigits.c3
@@ -0,0 +1,25 @@
+module binarydigits;
+import std::math;
+import libc;
+fn void main()
+{
+    for (int i = 0; i < 20; i++)
+    {
+        String s = bin(i);
+        defer s.destroy();
+        libc::printf("%s\n", s.zstr());
+    }
+}
+
+fn String bin(int x)
+{
+    int bits = 1 + (int)(x == 0 ? 0 : math::log10((double)(x)) / math::log10(2));
+    String str;
+    str.append_repeat('0', bits);
+    for (int i = 0; i < bits; i++)
+    {
+        str.set((usize)(bits - i - 1), x & 1 ? '1' : '0');
+        x >>= 1;
+    }
+    return str;
+}
\ No newline at end of file
diff --git a/resources/examples/guess_number.c3 b/resources/examples/guess_number.c3
index ae41b0d56..926e71148 100644
--- a/resources/examples/guess_number.c3
+++ b/resources/examples/guess_number.c3
@@ -1,5 +1,4 @@
 module guess_number;
-import std::mem;
 import std::io;
 import libc;
 
@@ -34,7 +33,7 @@ fn int! askGuess(int high)
 fn char[]! readLine()
 {
 	char* chars = mem::talloc(1024)?;
-	isize loaded = getline(&chars, &&(usize)1023, 2libc::stdin());
+	isize loaded = getline(&chars, &&(usize)1023, libc::stdin());
 	if (loaded < 0) return InputResult.FAILED_TO_READ!;
 	chars[loaded] = 0;
 	return chars[0..(loaded - 1)];
diff --git a/resources/examples/notworking/binarydigits.c3 b/resources/examples/notworking/binarydigits.c3
deleted file mode 100644
index edf053129..000000000
--- a/resources/examples/notworking/binarydigits.c3
+++ /dev/null
@@ -1,21 +0,0 @@
-module binarydigits;
-
-fn int main()
-{
-    fot (int i = 0; i < 20; i++)
-    {
-        printf("%s\n", bin(i));
-    }
-}
-
-fn string bin(int x)
-{
-    int bits = (x == 0) ? 1 : log10((double)(x)) / log10(2);
-    string ret = str.make_repeat('0' as bits);
-    for (int i = 0; i < bits; i++)
-    {
-        ret[bits - i - 1] = x & 1 ? '1' : '0';
-        x >>= 1;
-    }
-    return ret;
-}
\ No newline at end of file
diff --git a/resources/examples/notworking/map.c3 b/resources/examples/notworking/map.c3
index 5f10fb207..6f4ccb62a 100644
--- a/resources/examples/notworking/map.c3
+++ b/resources/examples/notworking/map.c3
@@ -1,9 +1,14 @@
-module map(Key, Type);
+module std::container::map <Key, Type>;
+
+fault MapResult
+{
+	KEY_NOT_FOUND
+}
 
 public struct Entry
 {
     Key key;
-    Type* value;
+    Type value;
     usize hash;
     Entry* next;
 }
@@ -13,34 +18,37 @@ public struct Map
     usize size;
     void* map;
     uint mod;
+    Allocator allocator;
 }
 
-public fn Map* Map.init(Map *map)
+/**
+ * @require map != null
+ **/
+public fn void Map.init(Map *map, Allocator allocator)
 {
-    *map = { };
-    return map;
+    map.allocator = allocator;
 }
 
-public fn Type* Map.valueForKey(Map *map, Key key)
+public fn Type! Map.valueForKey(Map *map, Key key)
 {
-    if (!map.map) return nil;
+    if (!map.map) return null;
     usize hash = key.hash();
     usize pos = hash & map.mod;
     Entry* entry = &map.map[pop];
-    if () return nil;
+    if (!entry) return MapResult.KEY_NOT_FOUND!;
     while (entry)
     {
         if (entry.hash == hash && entry.key == key) return entry.value;
         entry = entry.next;
     }
-    return nil;
+    return MapResult.KEY_NOT_FOUND!;
 }
 
-public fn Type *Map.setValueForKey(Map *map, Key key, Type *value)
+public fn Type *Map.set(Map *map, Key key, Type value)
 {
     if (!map.map)
     {
-        map.map = @calloc(Entry, 16);
+        map.map = allocator.calloc(Entry, 16);
         map.mod = 0x0F;
     }
 
@@ -66,42 +74,14 @@ public fn Type *Map.setValueForKey(Map *map, Key key, Type *value)
         {
             entry = entry.next;
         }
-        entry.next = @malloc(Entry);
+        entry.next = allocator.alloc(Entry);
         entry = entry.next;
     }
 }
 
-public fn usize Map.size(Vector *vector)
+public fn usize Map.size(Map* map)
 {
-    return vector.array.size;
+    return map.size;
 }
 
-public fn void Map.removeLast(Vector *vector)
-{
-    vector.array.pop();
-}
 
-public macro Vector.foreach(Vector *vector, macro void(Type value) body)
-{
-    for (usize i = 0, i < vector.array.size; i++)
-    {
-        @body(vector.array[i]);
-    }
-}
-
-test
-{
-    define IntVector = Vector(int);
-    IntVector vector = vector.init();
-    vector.add(1);
-    vector.add(2);
-    for (int i : vector)
-    {
-        printDigit(i);
-    }
-    @vector.foreach(int i)
-    {
-        printDigit(i);
-    }
-    vector.destroy();
-}
\ No newline at end of file
diff --git a/resources/examples/notworking/retry.c3 b/resources/examples/notworking/retry.c3
deleted file mode 100644
index 07829a273..000000000
--- a/resources/examples/notworking/retry.c3
+++ /dev/null
@@ -1,19 +0,0 @@
-module test;
-
-
-public macro retry(#function, int retries = 3)
-{
-    error e;
-    while (1)
-    {
-        auto! result = #function;
-        try (result) return result;
-        catch (e = result);
-    } while (retries-- > 0)
-    return e!;
-}
-
-fn void main()
-{
-    int! result = @retry(eventually_succeed());
-}
\ No newline at end of file
diff --git a/resources/examples/notworking/swap.c3 b/resources/examples/notworking/swap.c3
deleted file mode 100644
index 8ef12a9ca..000000000
--- a/resources/examples/notworking/swap.c3
+++ /dev/null
@@ -1,21 +0,0 @@
-public test;
-
-/**
- * @require parse(a = b), parse(b = a)
- */
-public macro void swap(&a, &b)
-{
-    typeof(a) temp = a;
-    a = b;
-    b = temp;
-}
-
-/**
- * @require parse(a = b), parse(b = a)
- */
-public macro void swap2(auto &a, auto &b)
-{
-    auto temp = a;
-    a = b;
-    b = temp;
-}
\ No newline at end of file
diff --git a/resources/examples/retry.c3 b/resources/examples/retry.c3
new file mode 100644
index 000000000..e1332353c
--- /dev/null
+++ b/resources/examples/retry.c3
@@ -0,0 +1,44 @@
+module test;
+import libc;
+
+fault TestErr
+{
+	NOPE
+}
+
+fn int! eventually_succeed()
+{
+	static int i = 0;
+	if (i++ < 3) return TestErr.NOPE!;
+	return i * 3;
+}
+
+macro @retry(#function, int retries = 3)
+{
+	var $Type = $typeof(#function);
+    anyerr e;
+    do
+    {
+        $Type! result = #function;
+        if (catch err = result)
+        {
+            e = err;
+            continue;
+        }
+        return result;
+    } while (retries-- > 0);
+    return e!;
+}
+
+fn void main()
+{
+    int! result = @retry(eventually_succeed());
+    if (try result)
+    {
+	    libc::printf("Got result: %d\n", result);
+    }
+    else
+    {
+        libc::printf("Failed :(\n");
+    }
+}
\ No newline at end of file
diff --git a/resources/examples/swap.c3 b/resources/examples/swap.c3
new file mode 100644
index 000000000..54366aaca
--- /dev/null
+++ b/resources/examples/swap.c3
@@ -0,0 +1,20 @@
+module test;
+import libc;
+
+/**
+ * @checked a = b, b = a
+ */
+macro void @swap(&a, &b)
+{
+    $typeof(a) temp = a;
+    a = b;
+    b = temp;
+}
+
+fn void main()
+{
+	int x = 123;
+	int y = 456;
+	@swap(x, y);
+	libc::printf("x: %d y: %d\n", x, y);
+}
\ No newline at end of file
diff --git a/src/compiler/llvm_codegen_expr.c b/src/compiler/llvm_codegen_expr.c
index 50b3f6032..4c72b1430 100644
--- a/src/compiler/llvm_codegen_expr.c
+++ b/src/compiler/llvm_codegen_expr.c
@@ -4909,6 +4909,9 @@ void llvm_emit_call_expr(GenContext *c, BEValue *result_value, Expr *expr)
 	{
 		BEValue no_err;
 
+		// Emit the current stack into the thread local or things will get messed up.
+		if (c->debug.last_ptr) llvm_store(c, c->debug.last_ptr, c->debug.stack_slot, type_alloca_alignment(type_voidptr));
+
 		// 17a. If we used the error var as the indirect recipient, then that will hold the error.
 		//      otherwise it's whatever value in be_value.
 		BEValue error_holder = *result_value;
@@ -4941,9 +4944,6 @@ void llvm_emit_call_expr(GenContext *c, BEValue *result_value, Expr *expr)
 		// 17f. Emit the "after" block.
 		llvm_emit_block(c, after_block);
 
-		// Emit the current stack into the thread local or things will get messed up.
-		if (c->debug.last_ptr) llvm_store(c, c->debug.last_ptr, c->debug.stack_slot, type_alloca_alignment(type_voidptr));
-
 		// 17g. If void, be_value contents should be skipped.
 		if (!prototype->ret_by_ref)
 		{
diff --git a/src/compiler/parse_global.c b/src/compiler/parse_global.c
index 43bb8e08f..5e7ea9508 100644
--- a/src/compiler/parse_global.c
+++ b/src/compiler/parse_global.c
@@ -2113,7 +2113,7 @@ static inline bool parse_doc_contract(ParseContext *c, AstId **docs_ref, DocDire
 	switch (kind)
 	{
 		case DOC_DIRECTIVE_CHECKED:
-			scratch_buffer_append("@require \"");
+			scratch_buffer_append("@checked \"");
 			break;
 		case DOC_DIRECTIVE_ENSURE:
 			scratch_buffer_append("@ensure \"");
diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index f34c3eda6..f410cbbed 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -1768,6 +1768,7 @@ bool sema_expr_analyse_macro_call(SemaContext *context, Expr *call_expr, Expr *s
 	};
 
 	if (!sema_expr_analyse_call_invocation(context, call_expr, callee, &failable)) return false;
+
 	Expr **args = call_expr->call_expr.arguments;
 	VECEACH(params, i)
 	{