diff --git a/doc/rst/language/spec/task-parallelism-and-synchronization.rst b/doc/rst/language/spec/task-parallelism-and-synchronization.rst
index 5ebaec5cad62..80cddc62e2ce 100644
--- a/doc/rst/language/spec/task-parallelism-and-synchronization.rst
+++ b/doc/rst/language/spec/task-parallelism-and-synchronization.rst
@@ -67,7 +67,10 @@ Tasks are considered to be created when execution reaches the start of a
 actually executed depends on the Chapel implementation and run-time
 execution state.
 
-A task is represented as a call to a *task function*, whose body
+Tasks created by ``begin``, ``cobegin``, and ``coforall`` can depend upon
+each other, even if that leads to the program not being serializable.
+
+A task is implemented as a call to a *task function*, whose body
 contains the Chapel code for the task. Variables defined in outer scopes
 are considered to be passed into a task function by default intent,
 unless a different *task intent* is specified explicitly by a
@@ -712,6 +715,10 @@ continue statements may not be used to exit a sync statement block.
 The Serial Statement
 --------------------
 
+.. note::
+
+   The ``serial`` statement is unstable and likely to be deprecated.
+
 The ``serial`` statement can be used to dynamically disable parallelism.
 The syntax is:
 
diff --git a/frontend/lib/uast/post-parse-checks.cpp b/frontend/lib/uast/post-parse-checks.cpp
index c01cb7d35e79..84b0aa75289f 100644
--- a/frontend/lib/uast/post-parse-checks.cpp
+++ b/frontend/lib/uast/post-parse-checks.cpp
@@ -147,6 +147,7 @@ struct Visitor {
   void checkCStringLiteral(const CStringLiteral* node);
   void checkAllowedImplementsTypeIdent(const Implements* impl, const Identifier* node);
   void checkOtherwiseAfterWhens(const Select* sel);
+  void checkUnstableSerial(const Serial* ser);
   /*
   TODO
   void checkProcedureFormalsAgainstRetType(const Function* node);
@@ -191,6 +192,7 @@ struct Visitor {
   void visit(const PrimCall* node);
   void visit(const Return* node);
   void visit(const Select* node);
+  void visit(const Serial* node);
   void visit(const TypeQuery* node);
   void visit(const Union* node);
   void visit(const Use* node);
@@ -1556,6 +1558,17 @@ void Visitor::checkOtherwiseAfterWhens(const Select* sel) {
   }
 }
 
+void Visitor::visit(const Serial* node) {
+  checkUnstableSerial(node);
+}
+
+void Visitor::checkUnstableSerial(const Serial* ser) {
+  if (shouldEmitUnstableWarning(ser)) {
+    warn(ser, "'serial' statements are unstable "
+              "and likely to be deprecated in a future release");
+  }
+}
+
 void Visitor::visit(const Yield* node) {
   const AstNode* blockingNode;
   const AstNode* allowingNode;
diff --git a/test/unstable/serial.chpl b/test/unstable/serial.chpl
new file mode 100644
index 000000000000..6283314ec6b3
--- /dev/null
+++ b/test/unstable/serial.chpl
@@ -0,0 +1,13 @@
+serial {
+  coforall i in 1..100 {
+    writeln("hello ", i);
+  }
+}
+
+proc main() {
+  serial {
+    forall i in 1..100 {
+      writeln("goodbye ", i);
+    }
+  }
+}
diff --git a/test/unstable/serial.good b/test/unstable/serial.good
new file mode 100644
index 000000000000..df60d4a53bf9
--- /dev/null
+++ b/test/unstable/serial.good
@@ -0,0 +1,203 @@
+serial.chpl:1: warning: 'serial' statements are unstable and likely to be deprecated in a future release
+serial.chpl:7: In function 'main':
+serial.chpl:8: warning: 'serial' statements are unstable and likely to be deprecated in a future release
+hello 1
+hello 2
+hello 3
+hello 4
+hello 5
+hello 6
+hello 7
+hello 8
+hello 9
+hello 10
+hello 11
+hello 12
+hello 13
+hello 14
+hello 15
+hello 16
+hello 17
+hello 18
+hello 19
+hello 20
+hello 21
+hello 22
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+hello 24
+hello 25
+hello 26
+hello 27
+hello 28
+hello 29
+hello 30
+hello 31
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+hello 33
+hello 34
+hello 35
+hello 36
+hello 37
+hello 38
+hello 39
+hello 40
+hello 41
+hello 42
+hello 43
+hello 44
+hello 45
+hello 46
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+hello 49
+hello 50
+hello 51
+hello 52
+hello 53
+hello 54
+hello 55
+hello 56
+hello 57
+hello 58
+hello 59
+hello 60
+hello 61
+hello 62
+hello 63
+hello 64
+hello 65
+hello 66
+hello 67
+hello 68
+hello 69
+hello 70
+hello 71
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+hello 73
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+hello 75
+hello 76
+hello 77
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+hello 79
+hello 80
+hello 81
+hello 82
+hello 83
+hello 84
+hello 85
+hello 86
+hello 87
+hello 88
+hello 89
+hello 90
+hello 91
+hello 92
+hello 93
+hello 94
+hello 95
+hello 96
+hello 97
+hello 98
+hello 99
+hello 100
+goodbye 1
+goodbye 2
+goodbye 3
+goodbye 4
+goodbye 5
+goodbye 6
+goodbye 7
+goodbye 8
+goodbye 9
+goodbye 10
+goodbye 11
+goodbye 12
+goodbye 13
+goodbye 14
+goodbye 15
+goodbye 16
+goodbye 17
+goodbye 18
+goodbye 19
+goodbye 20
+goodbye 21
+goodbye 22
+goodbye 23
+goodbye 24
+goodbye 25
+goodbye 26
+goodbye 27
+goodbye 28
+goodbye 29
+goodbye 30
+goodbye 31
+goodbye 32
+goodbye 33
+goodbye 34
+goodbye 35
+goodbye 36
+goodbye 37
+goodbye 38
+goodbye 39
+goodbye 40
+goodbye 41
+goodbye 42
+goodbye 43
+goodbye 44
+goodbye 45
+goodbye 46
+goodbye 47
+goodbye 48
+goodbye 49
+goodbye 50
+goodbye 51
+goodbye 52
+goodbye 53
+goodbye 54
+goodbye 55
+goodbye 56
+goodbye 57
+goodbye 58
+goodbye 59
+goodbye 60
+goodbye 61
+goodbye 62
+goodbye 63
+goodbye 64
+goodbye 65
+goodbye 66
+goodbye 67
+goodbye 68
+goodbye 69
+goodbye 70
+goodbye 71
+goodbye 72
+goodbye 73
+goodbye 74
+goodbye 75
+goodbye 76
+goodbye 77
+goodbye 78
+goodbye 79
+goodbye 80
+goodbye 81
+goodbye 82
+goodbye 83
+goodbye 84
+goodbye 85
+goodbye 86
+goodbye 87
+goodbye 88
+goodbye 89
+goodbye 90
+goodbye 91
+goodbye 92
+goodbye 93
+goodbye 94
+goodbye 95
+goodbye 96
+goodbye 97
+goodbye 98
+goodbye 99
+goodbye 100