diff --git a/tests/hard_coded/Mmake b/tests/hard_coded/Mmake
index c1604ce91..02422acaa 100644
--- a/tests/hard_coded/Mmake
+++ b/tests/hard_coded/Mmake
@@ -8,6 +8,7 @@ include ../Mmake.common
 
 PROGS=	\
 	address_of_builtins \
+	agg \
 	bidirectional \
 	c_write_string \
 	cc_nondet_disj \
@@ -44,10 +45,6 @@ PROGS=	\
 	write \
 	write_reg1
 
-# deep_copy_bug.exp and write.exp are broken; io__write doesn't write
-# equivalence types correctly, due to a bug in mercury_compare_type_info()
-# in library/std_util.m
-
 #-----------------------------------------------------------------------------#
 
 # some tests need to be compiled with particular options
diff --git a/tests/hard_coded/agg.exp b/tests/hard_coded/agg.exp
new file mode 100644
index 000000000..6b759b3ed
--- /dev/null
+++ b/tests/hard_coded/agg.exp
@@ -0,0 +1 @@
+9 - (285 - yes(1))
diff --git a/tests/hard_coded/agg.m b/tests/hard_coded/agg.m
new file mode 100644
index 000000000..708077cf6
--- /dev/null
+++ b/tests/hard_coded/agg.m
@@ -0,0 +1,123 @@
+% This is a regression test for a couple of bugs relating to
+% code generation for higher-order code.
+
+:- module agg.
+
+:- interface.
+
+:- import_module std_util.
+
+:- type agg_func(T, S) ---> agg(S, func(S, T) = S).
+:- inst agg_mode = bound(agg(ground, func(in, in) = out is det)).
+:- mode agg_in :: agg_mode -> agg_mode.
+:- mode agg_out :: free -> agg_mode.
+
+:- pred aggregate(pred(T), agg_func(T, S), S).
+:- mode aggregate(pred(out) is multi, agg_in, out) is det.
+:- mode aggregate(pred(out) is nondet, agg_in, out) is det.
+
+:- func agg_pair(agg_func(T, S1), agg_func(T, S2)) = agg_func(T, pair(S1, S2)).
+:- mode agg_pair(agg_in, agg_in) = agg_out is det.
+
+:- func count = agg_func(T, int).
+:- mode count = agg_out is det.
+
+:- func count(pred(T)) = int.
+:- mode count(pred(out) is multi) = out is det.
+:- mode count(pred(out) is nondet) = out is det.
+
+:- func sum(func(T) = int) = agg_func(T, int).
+:- mode sum(func(in) = out is det) = agg_out is det.
+
+:- func sum_agg(pred(T), func(T) = int) = int.
+:- mode sum_agg(pred(out) is multi, func(in) = out is det) = out is det.
+:- mode sum_agg(pred(out) is nondet, func(in) = out is det) = out is det.
+
+:- func avg_agg(pred(T), func(T) = int) = maybe(float).
+:- mode avg_agg(pred(out) is multi, func(in) = out is det) = out is det.
+:- mode avg_agg(pred(out) is nondet, func(in) = out is det) = out is det.
+
+:- func min(func(T) = int) = agg_func(T, maybe(int)).
+:- mode min(func(in) = out is det) = agg_out is det.
+
+:- func sum_and_min(func(T) = int) = agg_func(T, pair(int, maybe(int))).
+:- mode sum_and_min(func(in) = out is det) = agg_out is det.
+
+:- func sumF(func(T) = float) = agg_func(T, float).
+:- mode sumF(func(in) = out is det) = agg_out is det.
+
+:- func wsumF(func(T) = pair(float)) = agg_func(T, float).
+:- mode wsumF(func(in) = out is det) = agg_out is det.
+
+:- func minF(func(T) = float) = agg_func(T, maybe(float)).
+:- mode minF(func(in) = out is det) = agg_out is det.
+
+:- func sumF_and_minF(func(T) = float) = agg_func(T, pair(float, maybe(float))).
+:- mode sumF_and_minF(func(in) = out is det) = agg_out is det.
+
+:- import_module io.
+
+:- pred main(io__state::di, io__state::uo) is det.
+
+:- implementation.
+
+:- import_module list.
+
+aggregate(P, agg(S0, F), S) :-
+	A = (pred(Val::in, Acc::in, F(Acc, Val)::out) is det),
+	solutions(P, L), list__foldl(A, L, S0, S).
+
+agg_pair(agg(S1, F1), agg(S2, F2)) = agg(S1-S2, F) :-
+	F = (func(Acc1-Acc2, Val) = F1(Acc1, Val)-F2(Acc2, Val)).
+	
+:- import_module int.
+
+count = agg(0, func(X, _) = X + 1).
+
+count(P) = C :- aggregate(P, count, C).
+
+sum(F) = agg(0, func(X, Y) = X + F(Y)).
+
+sum_agg(P, F) = S :- aggregate(P, sum(F), S).
+
+avg_agg(P, F) = A :-
+	aggregate(P, agg_pair(count, sum(F)), C-S),
+	( C = 0 ->
+		A = no
+    	;	int__to_float(C, C1),
+		int__to_float(S, S1),
+		A = yes(S1/C1)
+	).
+
+min(F) = agg(no, func(Acc, Val) = min(Acc, F(Val))).
+
+:- func min(maybe(int), int) = maybe(int).
+min(no, Val) = yes(Val).
+min(yes(Acc), Val) = yes(Acc < Val -> Acc ; Val).
+
+sum_and_min(F) = agg_pair(sum(F), min(F)).
+
+:- import_module float.
+
+sumF(F) = agg(0.0, func(X, Y) = X + F(Y)).
+
+wsumF(F) = agg(0.0, (func(X, Y) = X + Y1 * Y2 :- F(Y) = Y1-Y2)).
+
+minF(F) = agg(no, func(Acc0, Val) = minF(Acc0, F(Val))).
+
+:- func minF(maybe(float), float) = maybe(float).
+minF(no, Val) = yes(Val).
+minF(yes(Acc), Val) = yes(Acc < Val -> Acc ; Val).
+
+sumF_and_minF(F) = agg_pair(sumF(F), minF(F)).
+
+:- import_module io.
+
+:- pred iota(int::in, int::in, int::out) is nondet.
+iota(N, M, I) :- N < M, (I = N ; iota(N+1, M, I)).
+
+main -->
+	{F = (func(N::in) = (M::out) is det :- M = N*N)},
+	{aggregate(iota(1, 10), agg_pair(count, agg_pair(sum(F), min(F))), A)},
+	io__write(A), io__nl.
+