923 – No constant folding for template value default arguments, D1 only

Error: expression 1 + 2 is not a valid template value argument
----------
void a(int b = 1+2)(){};
void main() {
 a!(1+2)(); // OK
 a(); // fails
}

workround: "a!()()" instead of "a()"
Added to DStress as
http://dstress.kuehne.cn/run/t/template_58_A.d
http://dstress.kuehne.cn/run/t/template_58_B.d
http://dstress.kuehne.cn/run/t/template_58_C.d
http://dstress.kuehne.cn/run/t/template_58_D.d
http://dstress.kuehne.cn/run/t/template_58_E.d 

This has already been fixed in D2. Here's the patch for D1.046. It's trivial.
Index: template.c
===================================================================
--- template.c	(revision 192)
+++ template.c	(working copy)
@@ -3951,6 +3951,7 @@
 	{ sinteger_t v;
 	 real_t r;
 
+	 ea = ea->optimize(WANTvalue | WANTinterpret);
 	 if (ea->op == TOKvar)
 	 {
 		sa = ((VarExp *)ea)->var;

Fixed DMD1.050.