diff --git a/Makefile b/Makefile
index acf727b..2342568 100644
--- a/Makefile
+++ b/Makefile
@@ -30,7 +30,7 @@ O=-Og
 CFLAGS=$(CCONFIG) $(EXTRA) $(CWARN) $(G) $(O) $(OSFLAGS) $(LTO)
 CFLAGS_PLACEHOLDER="$$(echo -e '\033[2m<flags...>\033[m')" 
 LDLIBS=-lgc -lcord -lm -lunistring -lgmp -ldl
-BUILTIN_OBJS=stdlib/siphash.o stdlib/arrays.o stdlib/bools.o stdlib/bytes.o stdlib/channels.o stdlib/nums.o stdlib/integers.o \
+BUILTIN_OBJS=stdlib/siphash.o stdlib/arrays.o stdlib/bools.o stdlib/bytes.o stdlib/nums.o stdlib/integers.o \
 						 stdlib/pointers.o stdlib/memory.o stdlib/text.o stdlib/threads.o stdlib/c_strings.o stdlib/tables.o \
 						 stdlib/types.o stdlib/util.o stdlib/files.o stdlib/ranges.o stdlib/shell.o stdlib/paths.o stdlib/rng.o \
 						 stdlib/optionals.o stdlib/patterns.o stdlib/metamethods.o stdlib/functiontype.o stdlib/stdlib.o \
diff --git a/README.md b/README.md
index 6b41144..16ffac5 100644
--- a/README.md
+++ b/README.md
@@ -77,8 +77,7 @@ of many language features or the other example programs/modules in
 - Built-in doctests with syntax highlighting
 - [Automatic command line argument parsing with type safety](docs/command-line-parsing.md)
 - [Easy interoperability with C](docs/c-interoperability.md)
-- Support for [POSIX threads](docs/threads.tm) and thread-safe message passing
-  queues over [channels](docs/channels.tm).
+- Support for [POSIX threads](docs/threads.tm) and mutex-guarded datastructures.
 - Built-in [data serialization and deserialization](docs/serialization.md).
 
 ## Dependencies
diff --git a/ast.c b/ast.c
index bfd1535..c6d5996 100644
--- a/ast.c
+++ b/ast.c
@@ -116,6 +116,7 @@ CORD ast_to_xml(ast_t *ast)
     T(Not, "<Not>%r</Not>", ast_to_xml(data.value))
     T(HeapAllocate, "<HeapAllocate>%r</HeapAllocate>", ast_to_xml(data.value))
     T(StackReference, "<StackReference>%r</StackReference>", ast_to_xml(data.value))
+    T(Mutexed, "<Mutexed>%r</Mutexed>", ast_to_xml(data.value))
     T(Min, "<Min>%r%r%r</Min>", ast_to_xml(data.lhs), ast_to_xml(data.rhs), optional_tagged("key", data.key))
     T(Max, "<Max>%r%r%r</Max>", ast_to_xml(data.lhs), ast_to_xml(data.rhs), optional_tagged("key", data.key))
     T(Array, "<Array>%r%r</Array>", optional_tagged_type("item-type", data.item_type), ast_list_to_xml(data.items))
@@ -127,7 +128,6 @@ CORD ast_to_xml(ast_t *ast)
       optional_tagged("default-value", data.default_value),
       ast_list_to_xml(data.entries), optional_tagged("fallback", data.fallback))
     T(TableEntry, "<TableEntry>%r%r</TableEntry>", ast_to_xml(data.key), ast_to_xml(data.value))
-    T(Channel, "<Channel>%r%r</Channel>", type_ast_to_xml(data.item_type), optional_tagged("max-size", data.max_size))
     T(Comprehension, "<Comprehension>%r%r%r%r%r</Comprehension>", optional_tagged("expr", data.expr),
       ast_list_to_xml(data.vars), optional_tagged("iter", data.iter),
       optional_tagged("filter", data.filter))
@@ -182,7 +182,6 @@ CORD type_ast_to_xml(type_ast_t *t)
       data.is_stack ? "yes" : "no", type_ast_to_xml(data.pointed))
     T(ArrayTypeAST, "<ArrayType>%r</ArrayType>", type_ast_to_xml(data.item))
     T(SetTypeAST, "<TableType>%r</TableType>", type_ast_to_xml(data.item))
-    T(ChannelTypeAST, "<ChannelType>%r</ChannelType>", type_ast_to_xml(data.item))
     T(TableTypeAST, "<TableType>%r %r</TableType>", type_ast_to_xml(data.key), type_ast_to_xml(data.value))
     T(FunctionTypeAST, "<FunctionType>%r %r</FunctionType>", arg_list_to_xml(data.args), type_ast_to_xml(data.ret))
     T(OptionalTypeAST, "<OptionalType>%r</OptionalType>", data.type)
diff --git a/ast.h b/ast.h
index 5687666..424eced 100644
--- a/ast.h
+++ b/ast.h
@@ -75,7 +75,6 @@ typedef enum {
     PointerTypeAST,
     ArrayTypeAST,
     SetTypeAST,
-    ChannelTypeAST,
     TableTypeAST,
     FunctionTypeAST,
     OptionalTypeAST,
@@ -103,7 +102,7 @@ struct type_ast_s {
         } PointerTypeAST;
         struct {
             type_ast_t *item;
-        } ArrayTypeAST, ChannelTypeAST;
+        } ArrayTypeAST;
         struct {
             type_ast_t *key, *value;
             ast_t *default_value;
@@ -128,9 +127,9 @@ typedef enum {
     TextLiteral, TextJoin, PrintStatement,
     Declare, Assign,
     BinaryOp, UpdateAssign,
-    Not, Negative, HeapAllocate, StackReference,
+    Not, Negative, HeapAllocate, StackReference, Mutexed,
     Min, Max,
-    Array, Channel, Set, Table, TableEntry, Comprehension,
+    Array, Set, Table, TableEntry, Comprehension,
     FunctionDef, Lambda,
     FunctionCall, MethodCall,
     Block,
@@ -194,7 +193,7 @@ struct ast_s {
         } BinaryOp, UpdateAssign;
         struct {
             ast_t *value;
-        } Not, Negative, HeapAllocate, StackReference;
+        } Not, Negative, HeapAllocate, StackReference, Mutexed;
         struct {
             ast_t *lhs, *rhs, *key;
         } Min, Max;
@@ -202,10 +201,6 @@ struct ast_s {
             type_ast_t *item_type;
             ast_list_t *items;
         } Array;
-        struct {
-            type_ast_t *item_type;
-            ast_t *max_size;
-        } Channel;
         struct {
             type_ast_t *item_type;
             ast_list_t *items;
diff --git a/compile.c b/compile.c
index 373762c..07df756 100644
--- a/compile.c
+++ b/compile.c
@@ -64,6 +64,11 @@ static bool promote(env_t *env, ast_t *ast, CORD *code, type_t *actual, type_t *
     if (!can_promote(actual, needed))
         return false;
 
+    if (needed->tag == ClosureType && actual->tag == FunctionType) {
+        *code = CORD_all("((Closure_t){", *code, ", NULL})");
+        return true;
+    }
+
     // Optional promotion:
     if (needed->tag == OptionalType && type_eq(actual, Match(needed, OptionalType)->type)) {
         *code = promote_to_optional(actual, *code);
@@ -136,11 +141,6 @@ static bool promote(env_t *env, ast_t *ast, CORD *code, type_t *actual, type_t *
     if (needed->tag == TableType && actual->tag == TableType)
         return true;
 
-    if (needed->tag == ClosureType && actual->tag == FunctionType) {
-        *code = CORD_all("((Closure_t){", *code, ", NULL})");
-        return true;
-    }
-
     if (needed->tag == ClosureType && actual->tag == ClosureType)
         return true;
 
@@ -271,7 +271,6 @@ CORD compile_type(type_t *t)
     }
     case ArrayType: return "Array_t";
     case SetType: return "Table_t";
-    case ChannelType: return "Channel_t*";
     case TableType: return "Table_t";
     case FunctionType: {
         auto fn = Match(t, FunctionType);
@@ -298,7 +297,7 @@ CORD compile_type(type_t *t)
         type_t *nonnull = Match(t, OptionalType)->type;
         switch (nonnull->tag) {
         case CStringType: case FunctionType: case ClosureType:
-        case PointerType: case EnumType: case ChannelType:
+        case PointerType: case EnumType:
             return compile_type(nonnull);
         case TextType:
             return Match(nonnull, TextType)->lang ? compile_type(nonnull) : "OptionalText_t";
@@ -436,7 +435,7 @@ CORD check_none(type_t *t, CORD value)
 {
     t = Match(t, OptionalType)->type;
     if (t->tag == PointerType || t->tag == FunctionType || t->tag == CStringType
-        || t->tag == ChannelType || t == THREAD_TYPE)
+        || t == THREAD_TYPE)
         return CORD_all("(", value, " == NULL)");
     else if (t == MATCH_TYPE)
         return CORD_all("((", value, ").index.small == 0)");
@@ -1582,7 +1581,6 @@ CORD expr_as_text(env_t *env, CORD expr, type_t *t, CORD color)
     case TextType: return CORD_asprintf("Text$as_text(stack(%r), %r, %r)", expr, color, compile_type_info(env, t));
     case ArrayType: return CORD_asprintf("Array$as_text(stack(%r), %r, %r)", expr, color, compile_type_info(env, t));
     case SetType: return CORD_asprintf("Table$as_text(stack(%r), %r, %r)", expr, color, compile_type_info(env, t));
-    case ChannelType: return CORD_asprintf("Channel$as_text(stack(%r), %r, %r)", expr, color, compile_type_info(env, t));
     case TableType: return CORD_asprintf("Table$as_text(stack(%r), %r, %r)", expr, color, compile_type_info(env, t));
     case FunctionType: case ClosureType: return CORD_asprintf("Func$as_text(stack(%r), %r, %r)", expr, color, compile_type_info(env, t));
     case PointerType: return CORD_asprintf("Pointer$as_text(stack(%r), %r, %r)", expr, color, compile_type_info(env, t));
@@ -1988,7 +1986,6 @@ CORD compile_none(type_t *t)
     case ArrayType: return "NONE_ARRAY";
     case TableType: return "NONE_TABLE";
     case SetType: return "NONE_TABLE";
-    case ChannelType: return "NULL";
     case TextType: return "NONE_TEXT";
     case CStringType: return "NULL";
     case MomentType: return "NONE_MOMENT";
@@ -2127,6 +2124,9 @@ CORD compile(env_t *env, ast_t *ast)
         else
             return CORD_all("stack(", compile(env, subject), ")");
     }
+    case Mutexed: {
+        return CORD_all("mutexed(", compile(env, Match(ast, Mutexed)->value), ")");
+    }
     case Optional: {
         ast_t *value = Match(ast, Optional)->value;
         CORD value_code = compile(env, value);
@@ -2578,20 +2578,6 @@ CORD compile(env_t *env, ast_t *ast)
             return code;
         }
     }
-    case Channel: {
-        auto chan = Match(ast, Channel);
-        type_t *item_t = parse_type_ast(env, chan->item_type);
-        if (!can_send_over_channel(item_t))
-            code_err(ast, "This item type can't be sent over a channel because it contains reference to memory that may not be thread-safe.");
-        if (chan->max_size) {
-            CORD max_size = compile(env, chan->max_size);
-            if (!promote(env, chan->max_size, &max_size, get_type(env, chan->max_size), INT_TYPE))
-                code_err(chan->max_size, "This value must be an integer, not %T", get_type(env, chan->max_size));
-            return CORD_all("Channel$new(", max_size, ")");
-        } else {
-            return "Channel$new(I(INT32_MAX))";
-        }
-    }
     case Table: {
         auto table = Match(ast, Table);
         if (!table->entries) {
@@ -3092,41 +3078,6 @@ CORD compile(env_t *env, ast_t *ast)
                                 ", ", compile_type_info(env, self_value_t), ")");
             } else code_err(ast, "There is no '%s' method for tables", call->name);
         }
-        case ChannelType: {
-            type_t *item_t = Match(self_value_t, ChannelType)->item_type;
-            CORD padded_item_size = CORD_asprintf("%ld", type_size(item_t));
-            arg_t *front_default_end = new(arg_t, .name="front", .type=Type(BoolType), .default_val=FakeAST(Bool, false));
-            arg_t *front_default_start = new(arg_t, .name="front", .type=Type(BoolType), .default_val=FakeAST(Bool, true));
-            if (streq(call->name, "give")) {
-                self = compile_to_pointer_depth(env, call->self, 0, false);
-                arg_t *arg_spec = new(arg_t, .name="item", .type=item_t, .next=front_default_end);
-                return CORD_all("Channel$give_value(", self, ", ", compile_arguments(env, ast, arg_spec, call->args), ", ",
-                                padded_item_size, ")");
-            } else if (streq(call->name, "give_all")) {
-                self = compile_to_pointer_depth(env, call->self, 0, false);
-                arg_t *arg_spec = new(arg_t, .name="to_give", .type=Type(ArrayType, .item_type=item_t), .next=front_default_end);
-                return CORD_all("Channel$give_all(", self, ", ", compile_arguments(env, ast, arg_spec, call->args), ", ",
-                                padded_item_size, ")");
-            } else if (streq(call->name, "get")) {
-                self = compile_to_pointer_depth(env, call->self, 0, false);
-                arg_t *arg_spec = front_default_start;
-                return CORD_all("Channel$get_value(", self, ", ", compile_arguments(env, ast, arg_spec, call->args),
-                                ", ", compile_type(item_t), ", ", padded_item_size, ")");
-            } else if (streq(call->name, "peek")) {
-                self = compile_to_pointer_depth(env, call->self, 0, false);
-                arg_t *arg_spec = front_default_start;
-                return CORD_all("Channel$peek_value(", self, ", ", compile_arguments(env, ast, arg_spec, call->args),
-                                ", ", compile_type(item_t), ")");
-            } else if (streq(call->name, "clear")) {
-                self = compile_to_pointer_depth(env, call->self, 0, false);
-                (void)compile_arguments(env, ast, NULL, call->args);
-                return CORD_all("Channel$clear(", self, ")");
-            } else if (streq(call->name, "view")) {
-                self = compile_to_pointer_depth(env, call->self, 0, false);
-                (void)compile_arguments(env, ast, NULL, call->args);
-                return CORD_all("Channel$view(", self, ")");
-            } else code_err(ast, "There is no '%s' method for channels", call->name);
-        }
         case TableType: {
             auto table = Match(self_value_t, TableType);
             if (streq(call->name, "get")) {
@@ -3599,11 +3550,6 @@ CORD compile(env_t *env, ast_t *ast)
                 return CORD_all("Int64_to_Int((", compile_to_pointer_depth(env, f->fielded, 0, false), ").length)");
             code_err(ast, "There is no %s field on arrays", f->field);
         }
-        case ChannelType: {
-            if (streq(f->field, "max_size"))
-                return CORD_all("Int64_to_Int((", compile_to_pointer_depth(env, f->fielded, 0, false), ")->max_size)");
-            code_err(ast, "There is no %s field on arrays", f->field);
-        }
         case SetType: {
             if (streq(f->field, "items"))
                 return CORD_all("ARRAY_COPY((", compile_to_pointer_depth(env, f->fielded, 0, false), ").entries)");
@@ -3842,10 +3788,6 @@ CORD compile_type_info(env_t *env, type_t *t)
         type_t *item_type = Match(t, SetType)->item_type;
         return CORD_all("Set$info(", compile_type_info(env, item_type), ")");
     }
-    case ChannelType: {
-        type_t *item_t = Match(t, ChannelType)->item_type;
-        return CORD_asprintf("Channel$info(%r)", compile_type_info(env, item_t));
-    }
     case TableType: {
         auto table = Match(t, TableType);
         type_t *key_type = table->key_type;
diff --git a/docs/README.md b/docs/README.md
index 960ed4a..c1e6cf8 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -21,7 +21,6 @@ Information about Tomo's built-in types can be found here:
 - [Arrays](arrays.md)
 - [Booleans](booleans.md)
 - [Bytes](bytes.md)
-- [Channels](channels.md)
 - [Moment](moments.md)
 - [Enums](enums.md)
 - [Floating point numbers](nums.md)
diff --git a/docs/channels.md b/docs/channels.md
deleted file mode 100644
index ab61a82..0000000
--- a/docs/channels.md
+++ /dev/null
@@ -1,177 +0,0 @@
-# Channels
-
-Channels are a thread-safe message queue for communicating between threads,
-although they can also be used as a general-purpose queue.
-
-## Syntax
-
-The syntax to create a channel is `|:T|`, where `T` is the type that will be
-passed through the channel. You can also specify a maximum size for the
-channel, which will cause giving to block until the recipient has gotten from
-the channel if the maximum size is reached.
-
-```tomo
-channel := |:Int|
-channel:give(10)
-channel:give(20)
->> channel:get()
-= 10
->> channel:get()
-= 20
-
-small_channel := |:Int; max_size=5|
-```
-
-## Channel Methods
-
-### `give`
-
-**Description:**  
-Adds an item to the channel.
-
-**Signature:**  
-```tomo
-func give(channel:|T|, item: T, front: Bool = no -> Void)
-```
-
-**Parameters:**
-
-- `channel`: The channel to which the item will be added.
-- `item`: The item to add to the channel.
-- `front`: Whether to put the item at the front of the channel (as opposed to the back).
-
-**Returns:**  
-Nothing.
-
-**Example:**  
-```tomo
->> channel:give("Hello")
-```
-
----
-
-### `give_all`
-
-**Description:**  
-Adds multiple items to the channel.
-
-**Signature:**  
-```tomo
-func give_all(channel:|T|, items: [T], front: Bool = no -> Void)
-```
-
-**Parameters:**
-
-- `channel`: The channel to which the items will be added.
-- `items`: The array of items to add to the channel.
-- `front`: Whether to put the item at the front of the channel (as opposed to the back).
-
-**Returns:**  
-Nothing.
-
-**Example:**  
-```tomo
->> channel:give_all([1, 2, 3])
-```
-
----
-
-### `get`
-
-**Description:**  
-Removes and returns an item from the channel. If the channel is empty, it waits until an item is available.
-
-**Signature:**  
-```tomo
-func get(channel:|T|, front: Bool = yes -> T)
-```
-
-**Parameters:**
-
-- `channel`: The channel from which to remove an item.
-- `front`: Whether to put the item at the front of the channel (as opposed to the back).
-
-**Returns:**  
-The item removed from the channel.
-
-**Example:**  
-```tomo
->> channel:peek()
-= "Hello"
-```
-
----
-
-### `peek`
-
-**Description:**  
-Returns the next item that will come out of the channel, but without removing
-it. If the channel is empty, it waits until an item is available.
-
-**Signature:**  
-```tomo
-func peek(channel:|T|, front: Bool = yes -> T)
-```
-
-**Parameters:**
-
-- `channel`: The channel from which to remove an item.
-- `front`: Whether to put the item at the front of the channel (as opposed to the back).
-
-**Returns:**  
-The item removed from the channel.
-
-**Example:**  
-```tomo
->> channel:get()
-= "Hello"
-```
-
----
-
-### `clear`
-
-**Description:**  
-Removes all items from the channel.
-
-**Signature:**  
-```tomo
-func clear(channel:|T| -> Void)
-```
-
-**Parameters:**
-
-- `channel`: The mutable reference to the channel.
-
-**Returns:**  
-Nothing.
-
-**Example:**  
-```tomo
->> channel:clear()
-```
-
----
-
-### `view`
-
-**Description:**  
-Returns a list of all items currently in the channel without removing them.
-
-**Signature:**  
-```tomo
-func channel:view(->[T])
-```
-
-**Parameters:**
-
-- `channel`: The channel to view.
-
-**Returns:**  
-An array of items currently in the channel.
-
-**Example:**  
-```tomo
->> channel:view()
-= [1, 2, 3]
-```
diff --git a/docs/optionals.md b/docs/optionals.md
index 56b7ba1..84f886b 100644
--- a/docs/optionals.md
+++ b/docs/optionals.md
@@ -127,9 +127,9 @@ for line in lines:
 ## Implementation Notes
 
 The implementation of optional types is highly efficient and has no memory
-overhead for pointers, collection types (arrays, sets, tables, channels),
-booleans, texts, enums, nums, or integers (`Int` type only). This is done by
-using carefully chosen values, such as `0` for pointers, `2` for booleans, or a
+overhead for pointers, collection types (arrays, sets, tables), booleans,
+texts, enums, nums, or integers (`Int` type only). This is done by using
+carefully chosen values, such as `0` for pointers, `2` for booleans, or a
 negative length for arrays. However, for fixed-size integers (`Int64`, `Int32`,
 `Int16`, and `Int8`), bytes, and structs, an additional byte is required for
 out-of-band information about whether the value is none or not.
diff --git a/docs/threads.md b/docs/threads.md
index 68fdf7d..44f5967 100644
--- a/docs/threads.md
+++ b/docs/threads.md
@@ -2,7 +2,7 @@
 
 Tomo supports POSIX threads (pthreads) through the `Thread` type. The
 recommended practice is to have each thread interact with other threads only
-through thread-safe Channels with no other shared data.
+through mutex-guarded datastructures.
 
 ## Thread Methods
 
diff --git a/parse.c b/parse.c
index d63822c..774f8e7 100644
--- a/parse.c
+++ b/parse.c
@@ -52,7 +52,7 @@ int op_tightness[] = {
 
 static const char *keywords[] = {
     "yes", "xor", "while", "when", "use", "unless", "struct", "stop", "skip", "return",
-    "or", "not", "no", "mod1", "mod", "pass", "lang", "inline", "in", "if",
+    "or", "not", "no", "mutexed", "mod1", "mod", "pass", "lang", "inline", "in", "if",
     "func", "for", "extern", "enum", "else", "do", "deserialize", "defer", "and", "none",
     "_min_", "_max_", NULL,
 };
@@ -82,7 +82,6 @@ static ast_t *parse_optional_conditional_suffix(parse_ctx_t *ctx, ast_t *stmt);
 static ast_t *parse_optional_suffix(parse_ctx_t *ctx, ast_t *lhs);
 static arg_ast_t *parse_args(parse_ctx_t *ctx, const char **pos);
 static type_ast_t *parse_array_type(parse_ctx_t *ctx, const char *pos);
-static type_ast_t *parse_channel_type(parse_ctx_t *ctx, const char *pos);
 static type_ast_t *parse_func_type(parse_ctx_t *ctx, const char *pos);
 static type_ast_t *parse_non_optional_type(parse_ctx_t *ctx, const char *pos);
 static type_ast_t *parse_pointer_type(parse_ctx_t *ctx, const char *pos);
@@ -94,7 +93,6 @@ static PARSER(parse_array);
 static PARSER(parse_assignment);
 static PARSER(parse_block);
 static PARSER(parse_bool);
-static PARSER(parse_channel);
 static PARSER(parse_declaration);
 static PARSER(parse_defer);
 static PARSER(parse_do);
@@ -113,6 +111,7 @@ static PARSER(parse_int);
 static PARSER(parse_moment);
 static PARSER(parse_lambda);
 static PARSER(parse_lang_def);
+static PARSER(parse_mutexed);
 static PARSER(parse_namespace);
 static PARSER(parse_negative);
 static PARSER(parse_not);
@@ -616,15 +615,6 @@ type_ast_t *parse_array_type(parse_ctx_t *ctx, const char *pos) {
     return NewTypeAST(ctx->file, start, pos, ArrayTypeAST, .item=type);
 }
 
-type_ast_t *parse_channel_type(parse_ctx_t *ctx, const char *pos) {
-    const char *start = pos;
-    if (!match(&pos, "|")) return NULL;
-    type_ast_t *type = expect(ctx, start, &pos, parse_type,
-                             "I couldn't parse a channel item type after this point");
-    expect_closing(ctx, &pos, "|", "I wasn't able to parse the rest of this channel");
-    return NewTypeAST(ctx->file, start, pos, ChannelTypeAST, .item=type);
-}
-
 type_ast_t *parse_pointer_type(parse_ctx_t *ctx, const char *pos) {
     const char *start = pos;
     bool is_stack;
@@ -667,7 +657,6 @@ type_ast_t *parse_non_optional_type(parse_ctx_t *ctx, const char *pos) {
     bool success = (false
         || (type=parse_pointer_type(ctx, pos))
         || (type=parse_array_type(ctx, pos))
-        || (type=parse_channel_type(ctx, pos))
         || (type=parse_table_type(ctx, pos))
         || (type=parse_set_type(ctx, pos))
         || (type=parse_type_name(ctx, pos))
@@ -751,21 +740,6 @@ static INLINE bool match_separator(const char **pos) { // Either comma or newlin
     }
 }
 
-PARSER(parse_channel) {
-    const char *start = pos;
-    if (!match(&pos, "|:")) return NULL;
-    type_ast_t *item_type = expect(ctx, pos-1, &pos, parse_type, "I couldn't parse a type for this channel");
-    ast_t *max_size = NULL;
-    if (match(&pos, ";")) {
-        whitespace(&pos);
-        const char *attr_start = pos;
-        if (match_word(&pos, "max_size") && match(&pos, "="))
-            max_size = expect(ctx, attr_start, &pos, parse_int, "I expected a maximum size for this channel");
-    }
-    expect_closing(ctx, &pos, "|", "I wasn't able to parse the rest of this channel");
-    return NewAST(ctx->file, start, pos, Channel, .item_type=item_type, .max_size=max_size);
-}
-
 PARSER(parse_array) {
     const char *start = pos;
     if (!match(&pos, "[")) return NULL;
@@ -1289,6 +1263,14 @@ PARSER(parse_stack_reference) {
     return ast;
 }
 
+PARSER(parse_mutexed) {
+    const char *start = pos;
+    if (!match_word(&pos, "mutexed")) return NULL;
+    spaces(&pos);
+    ast_t *val = expect(ctx, start, &pos, parse_term, "I expected an expression for this 'mutexed'");
+    return NewAST(ctx->file, start, pos, Mutexed, .value=val);
+}
+
 PARSER(parse_not) {
     const char *start = pos;
     if (!match_word(&pos, "not")) return NULL;
@@ -1633,7 +1615,6 @@ PARSER(parse_term_no_suffix) {
         || (term=parse_deserialize(ctx, pos))
         || (term=parse_var(ctx, pos))
         || (term=parse_array(ctx, pos))
-        || (term=parse_channel(ctx, pos))
         || (term=parse_reduction(ctx, pos))
         || (term=parse_pass(ctx, pos))
         || (term=parse_defer(ctx, pos))
@@ -1641,6 +1622,7 @@ PARSER(parse_term_no_suffix) {
         || (term=parse_stop(ctx, pos))
         || (term=parse_return(ctx, pos))
         || (term=parse_not(ctx, pos))
+        || (term=parse_mutexed(ctx, pos))
         || (term=parse_extern(ctx, pos))
         || (term=parse_inline_c(ctx, pos))
         );
diff --git a/stdlib/README.md b/stdlib/README.md
index 0d5b081..9916c06 100644
--- a/stdlib/README.md
+++ b/stdlib/README.md
@@ -19,7 +19,6 @@ some common functionality.
 - Arrays: [header](stdlib/arrays.h), [implementation](stdlib/arrays.c)
 - Bools: [header](stdlib/bools.h), [implementation](stdlib/bools.c)
 - Bytes: [header](stdlib/bytes.h), [implementation](stdlib/bytes.c)
-- Channels: [header](stdlib/channels.h), [implementation](stdlib/channels.c)
 - C Strings: [header](stdlib/c_strings.h), [implementation](stdlib/c_strings.c)
 - Files (used internally only): [header](stdlib/files.h), [implementation](stdlib/files.c)
 - Functiontype: [header](stdlib/functiontype.h), [implementation](stdlib/functiontype.c)
diff --git a/stdlib/channels.c b/stdlib/channels.c
deleted file mode 100644
index ee7ebde..0000000
--- a/stdlib/channels.c
+++ /dev/null
@@ -1,157 +0,0 @@
-// Functions that operate on channels
-
-#include <ctype.h>
-#include <err.h>
-#include <gc.h>
-#include <math.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <pthread.h>
-#include <sys/param.h>
-
-#include "arrays.h"
-#include "metamethods.h"
-#include "integers.h"
-#include "siphash.h"
-#include "text.h"
-#include "types.h"
-#include "util.h"
-
-public Channel_t *Channel$new(Int_t max_size)
-{
-    if (Int$compare_value(max_size, I_small(0)) <= 0)
-        fail("Cannot create a channel with a size less than one: %ld", max_size);
-    Channel_t *channel = new(Channel_t);
-    channel->items = (Array_t){};
-    channel->mutex = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
-    channel->cond = (pthread_cond_t)PTHREAD_COND_INITIALIZER;
-    channel->max_size = Int_to_Int64(max_size, false);
-    return channel;
-}
-
-public void Channel$give(Channel_t *channel, const void *item, bool front, int64_t padded_item_size)
-{
-    (void)pthread_mutex_lock(&channel->mutex);
-    while (channel->items.length >= channel->max_size)
-        pthread_cond_wait(&channel->cond, &channel->mutex);
-    Int_t index = front ? I_small(1) : I_small(0);
-    Array$insert(&channel->items, item, index, padded_item_size);
-    (void)pthread_mutex_unlock(&channel->mutex);
-    (void)pthread_cond_signal(&channel->cond);
-}
-
-public void Channel$give_all(Channel_t *channel, Array_t to_give, bool front, int64_t padded_item_size)
-{
-    if (to_give.length == 0) return;
-    (void)pthread_mutex_lock(&channel->mutex);
-    Int_t index = front ? I_small(1) : I_small(0);
-    if (channel->items.length + to_give.length >= channel->max_size) {
-        for (int64_t i = 0; i < to_give.length; i++) {
-            while (channel->items.length >= channel->max_size)
-                pthread_cond_wait(&channel->cond, &channel->mutex);
-            Array$insert(&channel->items, to_give.data + i*to_give.stride, index, padded_item_size);
-        }
-    } else {
-        Array$insert_all(&channel->items, to_give, index, padded_item_size);
-    }
-    (void)pthread_mutex_unlock(&channel->mutex);
-    (void)pthread_cond_signal(&channel->cond);
-}
-
-public void Channel$get(Channel_t *channel, void *out, bool front, int64_t item_size, int64_t padded_item_size)
-{
-    (void)pthread_mutex_lock(&channel->mutex);
-    while (channel->items.length == 0)
-        pthread_cond_wait(&channel->cond, &channel->mutex);
-    memcpy(out, channel->items.data + channel->items.stride * (front ? 0 : channel->items.length-1), (size_t)(item_size));
-    Int_t index = front ? I_small(1) : Int64_to_Int(channel->items.length);
-    Array$remove_at(&channel->items, index, I_small(1), padded_item_size);
-    (void)pthread_mutex_unlock(&channel->mutex);
-    (void)pthread_cond_signal(&channel->cond);
-}
-
-public void Channel$peek(Channel_t *channel, void *out, bool front, int64_t item_size)
-{
-    (void)pthread_mutex_lock(&channel->mutex);
-    while (channel->items.length == 0)
-        pthread_cond_wait(&channel->cond, &channel->mutex);
-    int64_t index = front ? 0 : channel->items.length-1;
-    memcpy(out, channel->items.data + channel->items.stride*index, (size_t)(item_size));
-    (void)pthread_mutex_unlock(&channel->mutex);
-    (void)pthread_cond_signal(&channel->cond);
-}
-
-public Array_t Channel$view(Channel_t *channel)
-{
-    (void)pthread_mutex_lock(&channel->mutex);
-    ARRAY_INCREF(channel->items);
-    Array_t ret = channel->items;
-    (void)pthread_mutex_unlock(&channel->mutex);
-    return ret;
-}
-
-public void Channel$clear(Channel_t *channel)
-{
-    (void)pthread_mutex_lock(&channel->mutex);
-    Array$clear(&channel->items);
-    (void)pthread_mutex_unlock(&channel->mutex);
-    (void)pthread_cond_signal(&channel->cond);
-}
-
-PUREFUNC public uint64_t Channel$hash(const void *channel, const TypeInfo_t *type)
-{
-    (void)type;
-    return siphash24(*(void**)channel, sizeof(Channel_t*));
-}
-
-PUREFUNC public int32_t Channel$compare(const void *x, const void *y, const TypeInfo_t*)
-{
-    return (*(Channel_t**)x > *(Channel_t**)y) - (*(Channel_t**)x < *(Channel_t**)y);
-}
-
-PUREFUNC public bool Channel$equal(const void *x, const void *y, const TypeInfo_t*)
-{
-    return (*(void**)x == *(void**)y);
-}
-
-public Text_t Channel$as_text(const void *channel, bool colorize, const TypeInfo_t *type)
-{
-    const TypeInfo_t *item_type = type->ChannelInfo.item;
-    if (!channel) {
-        Text_t typename = generic_as_text(NULL, false, item_type);
-        return Text$concat(colorize ? Text("\x1b[34;1m|:") : Text("|:"), typename, colorize ? Text("|\x1b[m") : Text("|"));
-    }
-    Text_t typename = generic_as_text(NULL, false, item_type);
-    return Text$concat(
-        colorize ? Text("\x1b[34;1m|:") : Text("|:"),
-        typename,
-        Text("|<"),
-        Int64$hex(*(int64_t*)channel, I_small(0), true, true),
-        colorize ? Text(">\x1b[m") : Text(">")
-    );
-}
-
-public PUREFUNC bool Channel$is_none(const void *obj, const TypeInfo_t*)
-{
-    return *(void**)obj == NULL;
-}
-
-public void Channel$serialize(const void *obj, FILE *out, Table_t *pointers, const TypeInfo_t *type)
-{
-    Channel_t *channel = (Channel_t*)obj;
-    Array$serialize(&channel->items, out, pointers, Array$info(type->ChannelInfo.item));
-    Int64$serialize(&channel->max_size, out, pointers, &Int64$info);
-}
-
-public void Channel$deserialize(FILE *in, void *outval, Array_t *pointers, const TypeInfo_t *type)
-{
-    Channel_t *channel = new(Channel_t);
-    channel->mutex = (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER;
-    channel->cond = (pthread_cond_t)PTHREAD_COND_INITIALIZER;
-    Array$deserialize(in, &channel->items, pointers, Array$info(type->ChannelInfo.item));
-    Int64$deserialize(in, &channel->max_size, pointers, &Int64$info);
-    *(Channel_t**)outval = channel;
-}
-
-// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0
diff --git a/stdlib/channels.h b/stdlib/channels.h
deleted file mode 100644
index cd0a82f..0000000
--- a/stdlib/channels.h
+++ /dev/null
@@ -1,45 +0,0 @@
-#pragma once
-
-// Functions that operate on channels (thread-safe arrays)
-
-#include <stdbool.h>
-
-#include "datatypes.h"
-#include "types.h"
-#include "util.h"
-
-Channel_t *Channel$new(Int_t max_size);
-void Channel$give(Channel_t *channel, const void *item, bool front, int64_t padded_item_size);
-#define Channel$give_value(channel, item, front, padded_item_size) \
-    ({ __typeof(item) _item = item; Channel$give(channel, &_item, front, padded_item_size); })
-void Channel$give_all(Channel_t *channel, Array_t to_give, bool front, int64_t padded_item_size);
-void Channel$get(Channel_t *channel, void *out, bool front, int64_t item_size, int64_t padded_item_size);
-#define Channel$get_value(channel, front, t, padded_item_size) \
-    ({ t _val; Channel$get(channel, &_val, front, sizeof(t), padded_item_size); _val; })
-void Channel$peek(Channel_t *channel, void *out, bool front, int64_t item_size);
-#define Channel$peek_value(channel, front, t) ({ t _val; Channel$peek(channel, &_val, front, sizeof(t)); _val; })
-void Channel$clear(Channel_t *channel);
-Array_t Channel$view(Channel_t *channel);
-PUREFUNC uint64_t Channel$hash(const void *channel, const TypeInfo_t *type);
-PUREFUNC int32_t Channel$compare(const void *x, const void *y, const TypeInfo_t *type);
-PUREFUNC bool Channel$equal(const void *x, const void *y, const TypeInfo_t *type);
-Text_t Channel$as_text(const void *channel, bool colorize, const TypeInfo_t *type);
-PUREFUNC bool Channel$is_none(const void *obj, const TypeInfo_t*);
-void Channel$serialize(const void *obj, FILE *out, Table_t *pointers, const TypeInfo_t*);
-void Channel$deserialize(FILE *in, void *outval, Array_t *pointers, const TypeInfo_t*);
-
-#define Channel$metamethods ((metamethods_t){ \
-    .as_text=Channel$as_text, \
-    .compare=Channel$compare, \
-    .equal=Channel$equal, \
-    .hash=Channel$hash, \
-    .is_none=Channel$is_none, \
-    .serialize=Channel$serialize, \
-    .deserialize=Channel$deserialize, \
-})
-
-#define Channel$info(item_info) &((TypeInfo_t){.size=sizeof(Channel_t), .align=__alignof__(Channel_t), \
-                                .tag=ChannelInfo, .ChannelInfo.item=item_info, \
-                                .metamethods=Channel$metamethods})
-
-// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0
diff --git a/stdlib/datatypes.h b/stdlib/datatypes.h
index 31a9963..9c3cabc 100644
--- a/stdlib/datatypes.h
+++ b/stdlib/datatypes.h
@@ -66,13 +66,6 @@ typedef struct Range_s {
     Int_t first, last, step;
 } Range_t;
 
-typedef struct {
-    Array_t items;
-    pthread_mutex_t mutex;
-    pthread_cond_t cond;
-    int64_t max_size;
-} Channel_t;
-
 enum text_type { TEXT_SHORT_ASCII, TEXT_ASCII, TEXT_SHORT_GRAPHEMES, TEXT_GRAPHEMES, TEXT_SUBTEXT };
 
 typedef struct Text_s {
diff --git a/stdlib/enums.c b/stdlib/enums.c
index b326e1a..fb0b93a 100644
--- a/stdlib/enums.c
+++ b/stdlib/enums.c
@@ -5,7 +5,6 @@
 
 #include "arrays.h"
 #include "bools.h"
-#include "channels.h"
 #include "functiontype.h"
 #include "integers.h"
 #include "metamethods.h"
diff --git a/stdlib/metamethods.c b/stdlib/metamethods.c
index 2871a96..c0e11cf 100644
--- a/stdlib/metamethods.c
+++ b/stdlib/metamethods.c
@@ -6,7 +6,6 @@
 #include "arrays.h"
 #include "bools.h"
 #include "bytes.h"
-#include "channels.h"
 #include "functiontype.h"
 #include "integers.h"
 #include "metamethods.h"
diff --git a/stdlib/stdlib.c b/stdlib/stdlib.c
index cb9d221..0266e78 100644
--- a/stdlib/stdlib.c
+++ b/stdlib/stdlib.c
@@ -621,4 +621,34 @@ public void sleep_num(double seconds)
     nanosleep(&ts, NULL);
 }
 
+static void use_mutexed(Closure_t fn, void *userdata)
+{
+    void (*call)(void*, void*) = fn.fn;
+    struct data_t {
+        pthread_mutex_t mutex;
+        char item[0] __attribute__ ((aligned (8)));
+    };
+    pthread_mutex_t *mutex = &((struct data_t*)userdata)->mutex;
+    pthread_mutex_lock(mutex);
+    void *mutexed_item = (void*)((struct data_t*)userdata)->item;
+    call(mutexed_item, fn.userdata);
+    pthread_mutex_unlock(mutex);
+}
+
+public Closure_t _mutexed(const void *item, size_t size)
+{
+    struct data_t {
+        pthread_mutex_t mutex;
+        char item[size] __attribute__ ((aligned (8)));
+    };
+    struct data_t *userdata = GC_MALLOC(sizeof(struct data_t));
+
+    pthread_mutex_init(&userdata->mutex, NULL);
+    memcpy(userdata->item, item, size);
+    return (Closure_t){
+        .fn=(void*)use_mutexed,
+        .userdata=(void*)userdata,
+    };
+}
+
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0
diff --git a/stdlib/stdlib.h b/stdlib/stdlib.h
index 7c9bd7e..c68442a 100644
--- a/stdlib/stdlib.h
+++ b/stdlib/stdlib.h
@@ -42,5 +42,7 @@ Closure_t spawn(Closure_t fn);
 bool pop_flag(char **argv, int *i, const char *flag, Text_t *result);
 void print_stack_trace(FILE *out, int start, int stop);
 void sleep_num(double seconds);
+public Closure_t _mutexed(const void *item, size_t size);
+#define mutexed(item) _mutexed((__typeof(item)[1]){item}, sizeof(item))
 
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0
diff --git a/stdlib/structs.c b/stdlib/structs.c
index 1ff5a91..b3b26bd 100644
--- a/stdlib/structs.c
+++ b/stdlib/structs.c
@@ -5,7 +5,6 @@
 
 #include "arrays.h"
 #include "bools.h"
-#include "channels.h"
 #include "functiontype.h"
 #include "metamethods.h"
 #include "optionals.h"
diff --git a/stdlib/tomo.h b/stdlib/tomo.h
index 0325793..10ac366 100644
--- a/stdlib/tomo.h
+++ b/stdlib/tomo.h
@@ -11,7 +11,6 @@
 #include "bools.h"
 #include "bytes.h"
 #include "c_strings.h"
-#include "channels.h"
 #include "datatypes.h"
 #include "enums.h"
 #include "functiontype.h"
diff --git a/stdlib/types.h b/stdlib/types.h
index f644390..3650839 100644
--- a/stdlib/types.h
+++ b/stdlib/types.h
@@ -29,7 +29,7 @@ struct TypeInfo_s {
     int64_t size, align;
     metamethods_t metamethods;
     struct { // Anonymous tagged union for convenience 
-        enum { OpaqueInfo, StructInfo, EnumInfo, PointerInfo, TextInfo, ArrayInfo, ChannelInfo, TableInfo, FunctionInfo,
+        enum { OpaqueInfo, StructInfo, EnumInfo, PointerInfo, TextInfo, ArrayInfo, TableInfo, FunctionInfo,
             OptionalInfo, TypeInfoInfo } tag;
         union {
             struct {} OpaqueInfo;
@@ -42,7 +42,7 @@ struct TypeInfo_s {
             } TextInfo;
             struct {
                 const TypeInfo_t *item;
-            } ArrayInfo, ChannelInfo;
+            } ArrayInfo;
             struct {
                 const TypeInfo_t *key, *value;
             } TableInfo;
diff --git a/test/optionals.tm b/test/optionals.tm
index 5aefedf..13a8dca 100644
--- a/test/optionals.tm
+++ b/test/optionals.tm
@@ -61,12 +61,6 @@ func maybe_c_string(should_i:Bool->CString?):
     else:
         return none
 
-func maybe_channel(should_i:Bool->|Int|?):
-    if should_i:
-        return |:Int|?
-    else:
-        return none
-
 func maybe_thread(should_i:Bool->Thread?):
     if should_i:
         return Thread.new(func(): pass)
@@ -244,19 +238,6 @@ func main():
             fail("Truthy: $nope")
         else: !! Falsey: $nope
 
-    do:
-        !! ...
-        !! Channels:
-        >> yep := maybe_channel(yes)
-        # No "=" test here because channels use addresses in the text version
-        >> nope := maybe_channel(no)
-        = none : |:Int|?
-        >> if yep: >> yep
-        else: fail("Falsey: $yep")
-        >> if nope:
-            fail("Truthy: $nope")
-        else: !! Falsey: $nope
-
     do:
         !! ...
         !! Threads:
diff --git a/test/threads.tm b/test/threads.tm
index 8fa6177..772c866 100644
--- a/test/threads.tm
+++ b/test/threads.tm
@@ -1,66 +1,74 @@
 enum Job(Increment(x:Int), Decrement(x:Int))
 
 func main():
-
     do:
-        >> channel := |:Int|
-        >> channel:give(10)
-        >> channel:give(20)
-        >> channel:give(30)
-        >> channel:view()
-        = [10, 20, 30]
-        >> channel:peek()
-        = 10
-        >> channel:peek(front=no)
-        = 30
-
-        >> channel:give(-10, front=yes)
-        >> channel:view()
-        = [-10, 10, 20, 30]
+        >> with_nums := mutexed [10, 20, 30]
+        with_nums(func(nums:&[Int]):
+            >> nums[]
+            = [10, 20, 30]
+            nums:insert(40)
+        )
+        with_nums(func(nums:&[Int]):
+            >> nums[]
+            = [10, 20, 30, 40]
+        )
 
 
-    jobs := |:Job; max_size=2|
-    >> jobs:give(Increment(5))
-    >> jobs:peek()
-    = Job.Increment(5)
+    with_jobs := mutexed [Job.Increment(5)]
+    enqueue_job := func(job:Job):
+        with_jobs(func(jobs:&[Job]): jobs:insert(job))
+    dequeue_job := func():
+        job := @none:Job
+        with_jobs(func(jobs:&[Job]): job[] = jobs:pop(1))
+        job[]
+
+    with_results := mutexed [:Int]
+    enqueue_result := func(result:Int):
+        with_results(func(results:&[Int]): results:insert(result))
+    dequeue_result := func():
+        result := @none:Int
+        repeat:
+            with_results(func(results:&[Int]): result[] = results:pop(1))
+            stop if result[]
+            sleep(0.00001)
+        result[]!
 
-    results := |:Int; max_size|
     >> thread := Thread.new(func():
         !! In another thread!
         repeat:
-            >> got := jobs:get()
-            when got is Increment(x):
-                >> results:give(x+1)
+            job := dequeue_job() or stop
+            when job is Increment(x):
+                enqueue_result(x + 1)
             is Decrement(x):
-                >> results:give(x-1)
+                enqueue_result(x - 1)
     )
 
-    >> jobs:give(Decrement(100))
-    >> jobs:give(Decrement(100))
-    >> jobs:give(Decrement(100))
-    >> jobs:give(Decrement(100))
-    >> jobs:give(Decrement(100))
-    >> jobs:give(Decrement(100))
+    enqueue_job(Decrement(100))
+    enqueue_job(Decrement(200))
+    enqueue_job(Decrement(300))
+    enqueue_job(Decrement(400))
+    enqueue_job(Decrement(500))
+    enqueue_job(Decrement(600))
 
-    >> results:get()
+    >> enqueue_job(Increment(1000))
+
+    >> dequeue_result()
     = 6
-
-    >> jobs:give(Increment(1000))
-    >> results:get()
+    >> dequeue_result()
     = 99
 
-    >> results:get()
-    = 99
-    >> results:get()
-    = 99
-    >> results:get()
-    = 99
-    >> results:get()
-    = 99
-    >> results:get()
-    = 99
+    >> dequeue_result()
+    = 199
+    >> dequeue_result()
+    = 299
+    >> dequeue_result()
+    = 399
+    >> dequeue_result()
+    = 499
+    >> dequeue_result()
+    = 599
 
-    >> results:get()
+    >> dequeue_result()
     = 1001
 
     !! Canceling...
diff --git a/typecheck.c b/typecheck.c
index f6a75ac..5bc3318 100644
--- a/typecheck.c
+++ b/typecheck.c
@@ -71,17 +71,6 @@ type_t *parse_type_ast(env_t *env, type_ast_t *ast)
                      type_size(item_t), ARRAY_MAX_STRIDE);
         return Type(SetType, .item_type=item_t);
     }
-    case ChannelTypeAST: {
-        type_ast_t *item_type = Match(ast, ChannelTypeAST)->item;
-        type_t *item_t = parse_type_ast(env, item_type);
-        if (!item_t) code_err(item_type, "I can't figure out what this type is.");
-        if (!can_send_over_channel(item_t))
-            code_err(ast, "This item type can't be sent over a channel because it contains reference to memory that may not be thread-safe.");
-        if (type_size(item_t) > ARRAY_MAX_STRIDE)
-            code_err(ast, "This channel holds items that take up %ld bytes, but the maximum supported size is %ld bytes.",
-                     type_size(item_t), ARRAY_MAX_STRIDE);
-        return Type(ChannelType, .item_type=item_t);
-    }
     case TableTypeAST: {
         auto table_type = Match(ast, TableTypeAST);
         type_ast_t *key_type_ast = table_type->key;
@@ -672,11 +661,6 @@ type_t *get_type(env_t *env, ast_t *ast)
             code_err(ast, "Sets cannot hold stack references because the set may outlive the reference's stack frame.");
         return Type(SetType, .item_type=item_type);
     }
-    case Channel: {
-        auto channel = Match(ast, Channel);
-        type_t *item_type = parse_type_ast(env, channel->item_type);
-        return Type(ChannelType, .item_type=item_type);
-    }
     case Table: {
         auto table = Match(ast, Table);
         type_t *key_type = NULL, *value_type = NULL;
@@ -787,7 +771,6 @@ type_t *get_type(env_t *env, ast_t *ast)
     }
     case FunctionCall: {
         auto call = Match(ast, FunctionCall);
-
         type_t *fn_type_t = get_type(env, call->fn);
         if (!fn_type_t)
             code_err(call->fn, "I couldn't find this function");
@@ -858,15 +841,6 @@ type_t *get_type(env_t *env, ast_t *ast)
             else if (streq(call->name, "without")) return self_value_t;
             else code_err(ast, "There is no '%s' method for sets", call->name);
         }
-        case ChannelType: {
-            if (streq(call->name, "clear")) return Type(VoidType);
-            else if (streq(call->name, "get")) return Match(self_value_t, ChannelType)->item_type;
-            else if (streq(call->name, "give")) return Type(VoidType);
-            else if (streq(call->name, "give_all")) return Type(VoidType);
-            else if (streq(call->name, "peek")) return Match(self_value_t, ChannelType)->item_type;
-            else if (streq(call->name, "view")) return Type(ArrayType, .item_type=Match(self_value_t, ChannelType)->item_type);
-            else code_err(ast, "There is no '%s' method for arrays", call->name);
-        }
         case TableType: {
             auto table = Match(self_value_t, TableType);
             if (streq(call->name, "bump")) return Type(VoidType);
@@ -976,6 +950,12 @@ type_t *get_type(env_t *env, ast_t *ast)
         }
         code_err(ast, "I only know how to get 'not' of boolean, numeric, and optional pointer types, not %T", t);
     }
+    case Mutexed: {
+        type_t *item_type = get_type(env, Match(ast, Mutexed)->value);
+        type_t *user_thunk = Type(ClosureType, Type(FunctionType, .args=new(arg_t, .name="object", .type=Type(PointerType, .pointed=item_type, .is_stack=true)),
+                                  .ret=Type(VoidType)));
+        return Type(ClosureType, Type(FunctionType, .args=new(arg_t, .name="fn", .type=user_thunk), .ret=Type(VoidType)));
+    }
     case BinaryOp: {
         auto binop = Match(ast, BinaryOp);
         type_t *lhs_t = get_type(env, binop->lhs),
diff --git a/types.c b/types.c
index ba866cf..08fceda 100644
--- a/types.c
+++ b/types.c
@@ -37,10 +37,6 @@ CORD type_to_cord(type_t *t) {
             auto array = Match(t, ArrayType);
             return CORD_asprintf("[%r]", type_to_cord(array->item_type));
         }
-        case ChannelType: {
-            auto array = Match(t, ChannelType);
-            return CORD_asprintf("||%r", type_to_cord(array->item_type));
-        }
         case TableType: {
             auto table = Match(t, TableType);
             if (table->default_value)
@@ -245,7 +241,6 @@ PUREFUNC bool has_heap_memory(type_t *t)
 {
     switch (t->tag) {
     case ArrayType: return true;
-    case ChannelType: return true;
     case TableType: return true;
     case SetType: return true;
     case PointerType: return true;
@@ -269,32 +264,6 @@ PUREFUNC bool has_heap_memory(type_t *t)
     }
 }
 
-PUREFUNC bool can_send_over_channel(type_t *t)
-{
-    switch (t->tag) {
-    case ArrayType: return true;
-    case ChannelType: return true;
-    case TableType: return true;
-    case PointerType: return false;
-    case OptionalType: return can_send_over_channel(Match(t, OptionalType)->type);
-    case StructType: {
-        for (arg_t *field = Match(t, StructType)->fields; field; field = field->next) {
-            if (!can_send_over_channel(field->type))
-                return false;
-        }
-        return true;
-    }
-    case EnumType: {
-        for (tag_t *tag = Match(t, EnumType)->tags; tag; tag = tag->next) {
-            if (tag->type && !can_send_over_channel(tag->type))
-                return false;
-        }
-        return true;
-    }
-    default: return true;
-    }
-}
-
 PUREFUNC bool has_stack_memory(type_t *t)
 {
     switch (t->tag) {
@@ -523,7 +492,6 @@ PUREFUNC size_t type_size(type_t *t)
     case TextType: return sizeof(Text_t);
     case ArrayType: return sizeof(Array_t);
     case SetType: return sizeof(Table_t);
-    case ChannelType: return sizeof(Channel_t*);
     case TableType: return sizeof(Table_t);
     case FunctionType: return sizeof(void*);
     case ClosureType: return sizeof(struct {void *fn, *userdata;});
@@ -607,7 +575,6 @@ PUREFUNC size_t type_align(type_t *t)
     case TextType: return __alignof__(Text_t);
     case SetType: return __alignof__(Table_t);
     case ArrayType: return __alignof__(Array_t);
-    case ChannelType: return __alignof__(Channel_t*);
     case TableType: return __alignof__(Table_t);
     case FunctionType: return __alignof__(void*);
     case ClosureType: return __alignof__(struct {void *fn, *userdata;});
@@ -706,10 +673,6 @@ type_t *get_field_type(type_t *t, const char *field_name)
         else if (streq(field_name, "microseconds")) return Type(IntType, .bits=TYPE_IBITS64);
         return NULL;
     }
-    case ChannelType: {
-        if (streq(field_name, "max_size")) return INT_TYPE;
-        return NULL;
-    }
     default: return NULL;
     }
 }
diff --git a/types.h b/types.h
index 2909883..1ddcc62 100644
--- a/types.h
+++ b/types.h
@@ -51,7 +51,6 @@ struct type_s {
         MomentType,
         TextType,
         ArrayType,
-        ChannelType,
         SetType,
         TableType,
         FunctionType,
@@ -85,7 +84,7 @@ struct type_s {
         } TextType;
         struct {
             type_t *item_type;
-        } ArrayType, ChannelType;
+        } ArrayType;
         struct {
             type_t *item_type;
         } SetType;
@@ -145,7 +144,6 @@ typedef enum {NUM_PRECISION_EQUAL, NUM_PRECISION_LESS, NUM_PRECISION_MORE, NUM_P
 PUREFUNC precision_cmp_e compare_precision(type_t *a, type_t *b);
 PUREFUNC bool has_heap_memory(type_t *t);
 PUREFUNC bool has_stack_memory(type_t *t);
-PUREFUNC bool can_send_over_channel(type_t *t);
 PUREFUNC bool can_promote(type_t *actual, type_t *needed);
 PUREFUNC const char *enum_single_value_tag(type_t *enum_type, type_t *t);
 PUREFUNC bool is_int_type(type_t *t);