From df94eecf119611a2fa8de1abb3abe59269be7550 Mon Sep 17 00:00:00 2001
From: dgp <dgp@users.sourceforge.net>
Date: Thu, 19 Apr 2018 01:39:38 +0000
Subject: An [array set] from a dict can only take shortcuts when the dict is
 "pure", that is, has no string rep.

---
 generic/tclVar.c |  2 +-
 tests/var.test   | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/generic/tclVar.c b/generic/tclVar.c
index e540c49..d4e5339 100644
--- a/generic/tclVar.c
+++ b/generic/tclVar.c
@@ -3411,7 +3411,7 @@ TclArraySet(
      * Install the contents of the dictionary or list into the array.
      */
 
-    if (arrayElemObj->typePtr == &tclDictType) {
+    if (arrayElemObj->typePtr == &tclDictType && arrayElemObj->bytes == NULL) {
 	Tcl_Obj *keyPtr, *valuePtr;
 	Tcl_DictSearch search;
 	int done;
diff --git a/tests/var.test b/tests/var.test
index 30e340e..aadeb34 100644
--- a/tests/var.test
+++ b/tests/var.test
@@ -761,6 +761,18 @@ test var-17.1 {TclArraySet [Bug 1669489]} -setup {
 } -cleanup {
     unset -nocomplain ::a ::elements
 } -result {}
+test var-17.2 {TclArraySet Dict shortcut only on pure value} -setup {
+    unset -nocomplain a d
+    set d {p 1 p 2}
+    dict get $d p
+    set foo 0
+} -body {
+    trace add variable a write "[list incr [namespace which -variable foo]];#"
+    array set a $d
+    set foo
+} -cleanup {
+    unset -nocomplain a d foo
+} -result 2
 
 test var-18.1 {array unset and unset traces: Bug 2939073} -setup {
     set already 0
-- 
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