John Aycock correctly pointed out that the grammar for

"power" was formally ambiguous.  Here's his fix.

Grammar/Grammar

@@ -79,7 +79,7 @@ shift_expr: arith_expr (('<<'|'>>') arith_expr)*
 arith_expr: term (('+'|'-') term)*
 term: factor (('*'|'/'|'%'|'//') factor)*
 factor: ('+'|'-'|'~') factor | power
-power: atom trailer* ('**' factor)*
+power: atom trailer* ['**' factor]
 atom: '(' [testlist] ')' | '[' [listmaker] ']' | '{' [dictmaker] '}' | '`' testlist '`' | NAME | NUMBER | STRING+
 listmaker: test ( list_for | (',' test)* [','] )
 lambdef: 'lambda' [varargslist] ':' test

Misc/ACKS

@@ -20,6 +20,7 @@ Oliver Andrich
 Ross Andrus
 Jason Asbahr
 David Ascher
+John Aycock
 Donovan Baarda
 Alfonso Baciero
 Stig Bakken

Python/graminit.c

@@ -1005,15 +1005,14 @@ static arc arcs_48_1[3] = {
 static arc arcs_48_2[1] = {
 	{119, 3},
 };
-static arc arcs_48_3[2] = {
-	{24, 2},
+static arc arcs_48_3[1] = {
 	{0, 3},
 };
 static state states_48[4] = {
 	{1, arcs_48_0},
 	{3, arcs_48_1},
 	{1, arcs_48_2},
-	{2, arcs_48_3},
+	{1, arcs_48_3},
 };
 static arc arcs_49_0[7] = {
 	{16, 1},