--- generic/tclCompCmds.c
+++ generic/tclCompCmds.c
@@ -1215,7 +1215,7 @@
 	tokenPtr = TokenAfter(tokenPtr);
     }
     if (parsePtr->numWords > 4) {
-	TclEmitInstInt1(INST_CONCAT1, parsePtr->numWords-2, envPtr);
+	TclEmitInstInt1(INST_CONCAT1, parsePtr->numWords-3, envPtr);
     }
 
     /*
--- tests/dict.test
+++ tests/dict.test
@@ -414,6 +414,9 @@
     catch {unset dictVar}
     set result
 } {1 {can't set "dictVar": variable is array}}
+test dict-13.10 {compiled dict append: crash case} {
+    apply {{} {dict append dictVar a o k}}
+} {a ok}
 
 test dict-14.1 {dict for command: syntax} {
     list [catch {dict for} msg] $msg