diff --git a/lib/std/collections/map.c3 b/lib/std/collections/map.c3
index f05399855..c66221a9f 100644
--- a/lib/std/collections/map.c3
+++ b/lib/std/collections/map.c3
@@ -8,6 +8,7 @@ const uint DEFAULT_INITIAL_CAPACITY = 16;
 const uint MAXIMUM_CAPACITY = 1u << 31;
 const float DEFAULT_LOAD_FACTOR = 0.75;
 const VALUE_IS_EQUATABLE = types::is_equatable(Value);
+const bool COPY_KEYS = types::implements_copy(Key);
 
 struct HashMap
 {
@@ -164,7 +165,14 @@ fn void HashMap.clear(&map)
 	{
 		Entry* entry = *entry_ref;
 		if (!entry) continue;
-		map.free_internal(entry);
+		Entry *next = entry.next;
+		while (next)
+		{
+			Entry *to_delete = next;
+			next = next.next;
+			map.free_entry(to_delete);
+		}
+		map.free_entry(entry);
 		*entry_ref = null;
 	}
 	map.count = 0;
@@ -255,6 +263,9 @@ fn bool HashMap.has_value(&map, Value v) @if(VALUE_IS_EQUATABLE)
 fn void HashMap.add_entry(&map, uint hash, Key key, Value value, uint bucket_index) @private
 {
 	Entry* entry = malloc(Entry, .using = map.allocator);
+	$if COPY_KEYS:
+	key = key.copy(map.allocator);
+	$endif
 	*entry = { .hash = hash, .key = key, .value = value, .next = map.table[bucket_index] };
 	map.table[bucket_index] = entry;
 	if (map.count++ >= map.threshold)
@@ -359,7 +370,7 @@ fn bool HashMap.remove_entry_for_key(&map, Key key) @private
 			{
 				prev.next = next;
 			}
-			map.free_internal(e);
+			map.free_entry(e);
 			return true;
 		}
 		prev = e;
@@ -372,15 +383,26 @@ fn void HashMap.create_entry(&map, uint hash, Key key, Value value, int bucket_i
 {
 	Entry *e = map.table[bucket_index];
 	Entry* entry = malloc(Entry, .using = map.allocator);
+	$if COPY_KEYS:
+	key = key.copy(map.allocator);
+	$endif
 	*entry = { .hash = hash, .key = key, .value = value, .next = map.table[bucket_index] };
 	map.table[bucket_index] = entry;
 	map.count++;
 }
 
+fn void HashMap.free_entry(&self, Entry *entry) @local
+{
+	$if COPY_KEYS:
+	entry.key.free(self.allocator);
+	$endif
+	self.free_internal(entry);
+}
+
 struct Entry
 {
 	uint hash;
 	Key key;
 	Value value;
 	Entry* next;
-}
+}
\ No newline at end of file
diff --git a/lib/std/core/mem.c3 b/lib/std/core/mem.c3
index 3c45695bb..9079b8c5a 100644
--- a/lib/std/core/mem.c3
+++ b/lib/std/core/mem.c3
@@ -177,19 +177,14 @@ macro bool equals(a, b, isz len = -1, usz $align = 0)
 	return true;
 }
 
-macro @clone(&value) @builtin
+macro @clone(&value, Allocator *using = mem::heap()) @builtin
 {
-	$typeof(value)* x = malloc($typeof(value));
+	$typeof(value)* x = malloc($typeof(value), .using = using);
 	*x = value;
 	return x;
 }
 
-macro @tclone(&value) @builtin
-{
-	$typeof(value)* x = talloc($typeof(value));
-	*x = value;
-	return x;
-}
+macro @tclone(&value) @builtin => @clone(value, mem::temp());
 
 macro type_alloc_must_be_aligned($Type)
 {
diff --git a/lib/std/core/string.c3 b/lib/std/core/string.c3
index bc19d5bb4..6ca1a07c5 100644
--- a/lib/std/core/string.c3
+++ b/lib/std/core/string.c3
@@ -346,6 +346,12 @@ fn String String.copy(s, Allocator* using = mem::heap())
 	str[len] = 0;
 	return (String)str[:len];
 }
+fn void String.free(&s, Allocator* using = mem::heap())
+{
+	if (!s.len) return;
+	mem::free(s.ptr, .using = using);
+	*s = "";
+}
 
 fn String String.tcopy(s) => s.copy(mem::temp()) @inline;
 
diff --git a/lib/std/core/types.c3 b/lib/std/core/types.c3
index 6dd019f59..37368fccd 100644
--- a/lib/std/core/types.c3
+++ b/lib/std/core/types.c3
@@ -229,6 +229,14 @@ macro bool is_equatable_type($Type)
 	$endif
 }
 
+/**
+ * Checks if a type implements the copy protocol.
+ **/
+macro bool implements_copy($Type)
+{
+	return $checks(Allocator *a, $Type x, $Type y = x.copy(a), $Type z = x.copy(), z.free(a), z.free());
+}
+
 macro bool is_equatable_value(value)
 {
 	return is_equatable_type($typeof(value));
diff --git a/releasenotes.md b/releasenotes.md
index 10c0bbcb7..0db05449c 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -107,6 +107,7 @@
 - `assert` may now take varargs for formatting.
  
 ### Stdlib changes
+- Hashmap keys implicitly copied if copy/free are defined.
 - Socket handling.
 - `csv` package.
 - Updated posix/win32 stdlib namespacing
diff --git a/src/version.h b/src/version.h
index ae6dfc6a5..94e7eb4f3 100644
--- a/src/version.h
+++ b/src/version.h
@@ -1 +1 @@
-#define COMPILER_VERSION "0.4.603"
\ No newline at end of file
+#define COMPILER_VERSION "0.4.604"
\ No newline at end of file
diff --git a/test/test_suite/errors/error_regression_2.c3t b/test/test_suite/errors/error_regression_2.c3t
index 940bf396c..9646919f8 100644
--- a/test/test_suite/errors/error_regression_2.c3t
+++ b/test/test_suite/errors/error_regression_2.c3t
@@ -405,7 +405,7 @@ panic_block:                                      ; preds = %assign_optional
   %29 = insertvalue %"any[]" undef, ptr %varargslots, 0
   %"#temp#" = insertvalue %"any[]" %29, i64 1, 1
   store %"any[]" %"#temp#", ptr %indirectarg, align 8
-  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7, i32 204, ptr byval(%"any[]") align 8 %indirectarg)
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7
   unreachable
 
 noerr_block:                                      ; preds = %after_check
@@ -478,7 +478,7 @@ panic_block39:                                    ; preds = %assign_optional37
   %53 = insertvalue %"any[]" undef, ptr %varargslots40, 0
   %"#temp#41" = insertvalue %"any[]" %53, i64 1, 1
   store %"any[]" %"#temp#41", ptr %indirectarg42, align 8
-  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7, i32 204, ptr byval(%"any[]") align 8 %indirectarg42)
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func
   unreachable
 
 noerr_block43:                                    ; preds = %after_check38
@@ -535,7 +535,7 @@ panic_block61:                                    ; preds = %assign_optional59
   %71 = insertvalue %"any[]" undef, ptr %varargslots62, 0
   %"#temp#63" = insertvalue %"any[]" %71, i64 1, 1
   store %"any[]" %"#temp#63", ptr %indirectarg64, align 8
-  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7, i32 204, ptr byval(%"any[]") align 8 %indirectarg64)
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func
   unreachable
 
 noerr_block65:                                    ; preds = %after_check60
@@ -606,7 +606,7 @@ panic_block81:                                    ; preds = %assign_optional79
   %95 = insertvalue %"any[]" undef, ptr %varargslots82, 0
   %"#temp#83" = insertvalue %"any[]" %95, i64 1, 1
   store %"any[]" %"#temp#83", ptr %indirectarg84, align 8
-  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7, i32 204, ptr byval(%"any[]") align 8 %indirectarg84)
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func
   unreachable
 
 noerr_block85:                                    ; preds = %after_check80
@@ -673,7 +673,7 @@ panic_block111:                                   ; preds = %assign_optional109
   %124 = insertvalue %"any[]" undef, ptr %varargslots112, 0
   %"#temp#113" = insertvalue %"any[]" %124, i64 1, 1
   store %"any[]" %"#temp#113", ptr %indirectarg114, align 8
-  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7, i32 204, ptr byval(%"any[]") align 8 %indirectarg114)
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func
   unreachable
 
 noerr_block115:                                   ; preds = %after_check110
@@ -730,7 +730,7 @@ panic_block133:                                   ; preds = %assign_optional131
   %142 = insertvalue %"any[]" undef, ptr %varargslots134, 0
   %"#temp#135" = insertvalue %"any[]" %142, i64 1, 1
   store %"any[]" %"#temp#135", ptr %indirectarg136, align 8
-  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7, i32 204, ptr byval(%"any[]") align 8 %indirectarg136)
+  call void @std.core.builtin.panicf(ptr @.panic_msg, i64 36, ptr @.file, i64 6, ptr @.func, i64 7
   unreachable
 
 noerr_block137:                                   ; preds = %after_check132
diff --git a/test/unit/stdlib/collections/copy_map.c3 b/test/unit/stdlib/collections/copy_map.c3
new file mode 100644
index 000000000..fe7c36873
--- /dev/null
+++ b/test/unit/stdlib/collections/copy_map.c3
@@ -0,0 +1,30 @@
+module test;
+import std::io;
+import std::collections::map;
+
+fn void! copy_map() @test
+{
+	TrackingAllocator alloc;
+	alloc.init(mem::heap());
+	io::printfn("Heap mem: %d", alloc.allocated());
+    mem::@scoped(&alloc)
+	{
+		HashMap(<String, int>) x;
+		x.init();
+		DString y;
+		y.append("hello");
+		x.set(y.as_str(), 123);
+		y.append("bye");
+		x.set(y.as_str(), 333);
+		y.clear();
+		y.append("bye");
+		x.set(y.as_str(), 444);
+		assert(x.get("hello")! == 123);
+		assert(x.get("hellobye")! == 333);
+		assert(x.get("bye")! == 444);
+		assert(alloc.allocated() > 0);
+		x.free();
+		y.free();
+		assert(alloc.allocated() == 0);
+	};
+}
\ No newline at end of file