diff --git a/Cargo.lock b/Cargo.lock
index 6c55c9ba..ef3f28a0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -23,9 +23,9 @@ checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
 [[package]]
 name = "az"
-version = "1.0.0"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e9bcd47d94aa4eb8c076b50fc61a75020789394ffb9bd74a180b3379130f6569"
+checksum = "d84e1d907bfc5795a6addb95ef8666141ee73c8f2f5250ff2a46bf4e4f4aec8a"
 
 [[package]]
 name = "base64"
@@ -470,9 +470,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.84"
+version = "0.2.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cca32fa0182e8c0989459524dc356b8f2b5c10f1b9eb521b7d182c03cf8c5ff"
+checksum = "7ccac4b00700875e6a07c6cde370d44d32fa01c5a65cdd2fca6858c479d28bb3"
 
 [[package]]
 name = "libsodium-sys"
@@ -1103,9 +1103,9 @@ dependencies = [
 
 [[package]]
 name = "ring"
-version = "0.16.19"
+version = "0.16.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "024a1e66fea74c66c66624ee5622a7ff0e4b73a13b4f5c326ddb50c708944226"
+checksum = "3053cf52e236a3ed746dfc745aa9cacf1b791d846bdaf412f60a8d7d6e17c8fc"
 dependencies = [
  "cc",
  "libc",
diff --git a/crates/prolog_parser/Cargo.lock b/crates/prolog_parser/Cargo.lock
new file mode 100644
index 00000000..f90f0d69
--- /dev/null
+++ b/crates/prolog_parser/Cargo.lock
@@ -0,0 +1,265 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "arrayvec"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd9fd44efafa8690358b7408d253adf110036b88f55672a933f01d616ad9b1b9"
+dependencies = [
+ "nodrop",
+]
+
+[[package]]
+name = "autocfg"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+
+[[package]]
+name = "az"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d84e1d907bfc5795a6addb95ef8666141ee73c8f2f5250ff2a46bf4e4f4aec8a"
+
+[[package]]
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+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a57fdb339d49833021b1fded600ed240ae907e33909d5511a61dff884df7f16e"
+dependencies = [
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "lexical"
+version = "2.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e0d09e60c187a6d0a3fa418aec8587c6a4ae9de872f6126f2134f319b5ed10d"
+dependencies = [
+ "cfg-if",
+ "lexical-core",
+ "rustc_version",
+]
+
+[[package]]
+name = "lexical-core"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2304bccb228c4b020f3a4835d247df0a02a7c4686098d4167762cfbbe4c5cb14"
+dependencies = [
+ "arrayvec",
+ "cfg-if",
+ "rustc_version",
+ "ryu",
+ "static_assertions",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.85"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ccac4b00700875e6a07c6cde370d44d32fa01c5a65cdd2fca6858c479d28bb3"
+
+[[package]]
+name = "nodrop"
+version = "0.1.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
+
+[[package]]
+name = "num-bigint"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "090c7f9998ee0ff65aa5b723e4009f7b217707f1fb5ea551329cc4d6231fb304"
+dependencies = [
+ "autocfg",
+ "num-integer",
+ "num-traits 0.2.14",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d2cc698a63b549a70bc047073d2949cce27cd1c7b0a4a862d08a8031bc2801db"
+dependencies = [
+ "autocfg",
+ "num-traits 0.2.14",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c000134b5dbf44adc5cb772486d335293351644b801551abe8f75c84cfa4aef"
+dependencies = [
+ "autocfg",
+ "num-bigint",
+ "num-integer",
+ "num-traits 0.2.14",
+]
+
+[[package]]
+name = "num-rug-adapter"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7470b6acf85abce0771203112db4181d03f7b8a6be49f0e842a78030192f8a58"
+dependencies = [
+ "libc",
+ "num-bigint",
+ "num-integer",
+ "num-rational",
+ "num-traits 0.2.14",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.1.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92e5113e9fd4cc14ded8e499429f396a20f98c772a47cc8622a736e1ec843c31"
+dependencies = [
+ "num-traits 0.2.14",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "ordered-float"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7eb5259643245d3f292c7a146b2df53bba24d7eab159410e648eb73dc164669d"
+dependencies = [
+ "num-traits 0.1.43",
+ "unreachable",
+]
+
+[[package]]
+name = "prolog_parser_rebis"
+version = "0.8.68"
+dependencies = [
+ "lexical",
+ "num-rug-adapter",
+ "ordered-float",
+ "rug",
+ "unicode_reader",
+]
+
+[[package]]
+name = "rug"
+version = "1.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e538d00da450a8e48aac7e6322e67b2dc86ec71a1feeac0e3954c4f07f01bc45"
+dependencies = [
+ "az",
+ "gmp-mpfr-sys",
+ "libc",
+]
+
+[[package]]
+name = "rustc_version"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
+dependencies = [
+ "semver",
+]
+
+[[package]]
+name = "ryu"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
+
+[[package]]
+name = "semver"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
+dependencies = [
+ "semver-parser",
+]
+
+[[package]]
+name = "semver-parser"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
+
+[[package]]
+name = "smallvec"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
+
+[[package]]
+name = "static_assertions"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f3eb36b47e512f8f1c9e3d10c2c1965bc992bd9cdb024fa581e2194501c83d3"
+
+[[package]]
+name = "unicode-segmentation"
+version = "1.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb0d2e7be6ae3a5fa87eed5fb451aff96f2573d2694942e40543ae0bbe19c796"
+
+[[package]]
+name = "unicode_reader"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b639121690b27acd92c97ed2b52c5e5e8d3d39482e943b4559695cef62f771a"
+dependencies = [
+ "smallvec",
+ "unicode-segmentation",
+]
+
+[[package]]
+name = "unreachable"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "382810877fe448991dfc7f0dd6e3ae5d58088fd0ea5e35189655f84e6814fa56"
+dependencies = [
+ "void",
+]
+
+[[package]]
+name = "void"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/crates/prolog_parser/tests/bom.rs b/crates/prolog_parser/tests/bom.rs
index 3be7278a..25b57104 100644
--- a/crates/prolog_parser/tests/bom.rs
+++ b/crates/prolog_parser/tests/bom.rs
@@ -1,8 +1,8 @@
-extern crate prolog_parser;
+extern crate prolog_parser_rebis;
 
-use prolog_parser::ast::*;
-use prolog_parser::lexer::{Lexer, Token};
-use prolog_parser::tabled_rc::TabledData;
+use prolog_parser_rebis::ast::*;
+use prolog_parser_rebis::lexer::{Lexer, Token};
+use prolog_parser_rebis::tabled_rc::TabledData;
 
 use std::rc::Rc;
 
diff --git a/crates/prolog_parser/tests/parse_tokens.rs b/crates/prolog_parser/tests/parse_tokens.rs
index 768445fd..3afb9164 100644
--- a/crates/prolog_parser/tests/parse_tokens.rs
+++ b/crates/prolog_parser/tests/parse_tokens.rs
@@ -1,8 +1,8 @@
-extern crate prolog_parser;
+extern crate prolog_parser_rebis;
 
-use prolog_parser::ast::*;
-use prolog_parser::lexer::{Lexer, Token};
-use prolog_parser::tabled_rc::TabledData;
+use prolog_parser_rebis::ast::*;
+use prolog_parser_rebis::lexer::{Lexer, Token};
+use prolog_parser_rebis::tabled_rc::TabledData;
 
 use std::rc::Rc;
 
diff --git a/src/lib/atts.pl b/src/lib/atts.pl
index 8fa16e11..fcd5b2c1 100644
--- a/src/lib/atts.pl
+++ b/src/lib/atts.pl
@@ -156,6 +156,8 @@ user:goal_expansion(Term, M:get_atts(Var, Attr)) :-
     nonvar(Term),
     Term = get_atts(Var, M, Attr).
 
+:- meta_predicate call_residue_vars(0, ?).
+
 call_residue_vars(Goal, Vars) :-
     '$get_attr_var_queue_delim'(B),
     call(Goal),
diff --git a/src/lib/clpz.pl b/src/lib/clpz.pl
index a4f66256..b7fa0ea7 100644
--- a/src/lib/clpz.pl
+++ b/src/lib/clpz.pl
@@ -5884,10 +5884,12 @@ difference_arcs([V|Vs], FL0) -->
 
 writeln(T) :- write(T), nl.
 
+:- meta_predicate must_succeed(0).
+
 must_succeed(G) :-
-    (G -> true
-     ;write(failed-G), halt
-    ).
+        (   G -> true
+        ;   throw(failed-G)
+        ).
 
 enumerate([], _) --> [].
 enumerate([N|Ns], V) -->
@@ -6047,6 +6049,8 @@ remove_attr(Var, Attr) :-
         functor(Term, Attr, 1),
         put_atts(Var, -Term).
 
+:- meta_predicate with_local_attributes(?, 0, ?).
+
 with_local_attributes(Vars, Goal, Result) :-
         catch((Goal,
                maplist(del_all_attrs, Vars),
@@ -7763,11 +7767,10 @@ zo_t(1, true).
    Generated predicates
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
-generated_clauses(Cs) :-
-        make_parse_clpz(Cs1),
-        make_parse_reified(Cs2),
-        make_matches(Cs3),
-        append([Cs1,Cs2,Cs3], Cs).
+term_expansion(make_parse_clpz, Clauses)    :- make_parse_clpz(Clauses).
+term_expansion(make_parse_reified, Clauses) :- make_parse_reified(Clauses).
+term_expansion(make_matches, Clauses)       :- make_matches(Clauses).
 
-:- initialization((generated_clauses(Cs),
-                   maplist(assertz, Cs))).
+make_parse_clpz.
+make_parse_reified.
+make_matches.
diff --git a/src/lib/dcgs.pl b/src/lib/dcgs.pl
index f9410d99..07b82b95 100644
--- a/src/lib/dcgs.pl
+++ b/src/lib/dcgs.pl
@@ -19,7 +19,7 @@ phrase(GRBody, S0, S) :-
     (  var(GRBody) ->
        throw(error(instantiation_error, phrase/3))
     ;  strip_module(GRBody, Module, GRBody0),
-       dcg_constr(GRBody0),
+       dcg_constr(GRBody0) ->
        (  var(Module) ->
           phrase_(GRBody0, S0, S)
        ;  phrase_(Module:GRBody0, S0, S)
@@ -31,9 +31,12 @@ phrase(GRBody, S0, S) :-
 
 phrase_([], S, S).
 phrase_(!, S, S).
+phrase_(_:[], S, S) :- !.
+phrase_(_:!, S, S) :- !.
 phrase_((A, B), S0, S) :-
     phrase(A, S0, S1), phrase(B, S1, S).
 phrase_(M:(A, B), S0, S) :-
+    !,
     phrase(M:A, S0, S1), phrase(M:B, S1, S).
 phrase_((A -> B ; C), S0, S) :-
     !,
@@ -50,23 +53,37 @@ phrase_(M:(A -> B ; C), S0, S) :-
 phrase_((A ; B), S0, S) :-
     (  phrase(A, S0, S) ; phrase(B, S0, S)  ).
 phrase_(M:(A ; B), S0, S) :-
+    !,
     (  phrase(M:A, S0, S) ; phrase(M:B, S0, S)  ).
 phrase_((A | B), S0, S) :-
     (  phrase(A, S0, S) ; phrase(B, S0, S)  ).
 phrase_(M:(A | B), S0, S) :-
+    !,
     (  phrase(M:A, S0, S) ; phrase(M:B, S0, S)  ).
 phrase_({G}, S0, S) :-
     (  call(G), S0 = S  ).
+phrase_(M:{G}, S0, S) :-
+    !,
+    (  call(M:G), S0 = S  ).
 phrase_(call(G), S0, S) :-
     call(G, S0, S).
+phrase_(M:call(G), S0, S) :-
+    !,
+    call(M:G, S0, S).
 phrase_((A -> B), S0, S) :-
     phrase((A -> B ; fail), S0, S).
 phrase_(M:(A -> B), S0, S) :-
+    !,
     phrase((M:A -> M:B ; fail), S0, S).
 phrase_(phrase(NonTerminal), S0, S) :-
     phrase(NonTerminal, S0, S).
+phrase_(M:phrase(NonTerminal), S0, S) :-
+    !,
+    phrase(M:NonTerminal, S0, S).
 phrase_([T|Ts], S0, S) :-
     append([T|Ts], S, S0).
+phrase_(_:[T|Ts], S0, S) :-
+    append([T|Ts], S, S0).
 
 
 % The same version of the below two dcg_rule clauses, but with module scoping.
diff --git a/src/lib/lists.pl b/src/lib/lists.pl
index c6160e55..0a799672 100644
--- a/src/lib/lists.pl
+++ b/src/lib/lists.pl
@@ -126,7 +126,7 @@ maplist(Cont, [E1|E1s], [E2|E2s], [E3|E3s], [E4|E4s], [E5|E5s], [E6|E6s], [E7|E7
 
 
 sum_list(Ls, S) :-
-        foldl(sum_, Ls, 0, S).
+        foldl(lists:sum_, Ls, 0, S).
 
 sum_(L, S0, S) :- S is S0 + L.
 
@@ -160,17 +160,17 @@ transpose(Ls, Ts) :-
 
 lists_transpose([], []).
 lists_transpose([L|Ls], Ts) :-
-        maplist(same_length(L), Ls),
-        foldl(transpose_, L, Ts, [L|Ls], _).
+        maplist(lists:same_length(L), Ls),
+        foldl(lists:transpose_, L, Ts, [L|Ls], _).
 
 transpose_(_, Fs, Lists0, Lists) :-
-        maplist(list_first_rest, Lists0, Fs, Lists).
+        maplist(lists:list_first_rest, Lists0, Fs, Lists).
 
 list_first_rest([L|Ls], L, Ls).
 
 
 list_to_set(Ls0, Ls) :-
-        maplist(with_var, Ls0, LVs0),
+        maplist(lists:with_var, Ls0, LVs0),
         keysort(LVs0, LVs),
         same_elements(LVs),
         pick_firsts(LVs0, Ls).
@@ -188,7 +188,7 @@ with_var(E, E-_).
 
 same_elements([]).
 same_elements([EV|EVs]) :-
-        foldl(unify_same, EVs, EV, _).
+        foldl(lists:unify_same, EVs, EV, _).
 
 unify_same(E-V, Prev-Var, E-V) :-
         (   Prev == E ->
@@ -221,13 +221,13 @@ nth0_search(N0, N, [_|Es], E) :-
 
 
 list_max([N|Ns], Max) :-
-    foldl(list_max_, Ns, N, Max).
+    foldl(lists:list_max_, Ns, N, Max).
 
 list_max_(N, Max0, Max) :-
     Max is max(N, Max0).
 
 list_min([N|Ns], Min) :-
-    foldl(list_min_, Ns, N, Min).
+    foldl(lists:list_min_, Ns, N, Min).
 
 list_min_(N, Min0, Min) :-
     Min is min(N, Min0).
diff --git a/src/lib/reif.pl b/src/lib/reif.pl
index 0e958356..092f93ec 100644
--- a/src/lib/reif.pl
+++ b/src/lib/reif.pl
@@ -4,6 +4,8 @@
 
 :- use_module(library(dif)).
 
+:- meta_predicate if_(0, 0, 0).
+
 if_(If_1, Then_0, Else_0) :-
     call(If_1, T),
     (  T == true  -> call(Then_0)
@@ -26,6 +28,8 @@ dif(X, Y, T) :-
 non(true, false).
 non(false, true).
 
+:- meta_predicate tfilter(1, ?, ?).
+
 tfilter(C_2, Es, Fs) :-
    i_tfilter(Es, C_2, Fs).
 
@@ -34,6 +38,8 @@ i_tfilter([E|Es], C_2, Fs0) :-
    if_(call(C_2, E), Fs0 = [E|Fs], Fs0 = Fs),
    i_tfilter(Es, C_2, Fs).
 
+:- meta_predicate tpartition(1, ?, ?).
+
 tpartition(P_2, Xs, Ts, Fs) :-
    i_tpartition(Xs, P_2, Ts, Fs).
 
@@ -44,12 +50,18 @@ i_tpartition([X|Xs], P_2, Ts0, Fs0) :-
       , ( Fs0 = [X|Fs], Ts0 = Ts ) ),
    i_tpartition(Xs, P_2, Ts, Fs).
 
+:- meta_predicate ','(0, 0, ?).
+
 ','(A_1, B_1, T) :-
     if_(A_1, call(B_1, T), T = false).
 
+:- meta_predicate ';'(0, 0, ?).
+
 ';'(A_1, B_1, T) :-
     if_(A_1, T = true, call(B_1, T)).
 
+:- meta_predicate cond_t(0, 0, ?).
+
 cond_t(If_1, Then_0, T) :-
    if_(If_1, ( Then_0, T = true ), T = false ).
 
@@ -60,8 +72,12 @@ i_memberd_t([], _, false).
 i_memberd_t([X|Xs], E, T) :-
    if_( X = E, T = true, i_memberd_t(Xs, E, T) ).
 
+:- meta_predicate tmember(1, ?).
+
 tmember(P_2, [X|Xs]) :-
    if_( call(P_2, X), true, tmember(P_2, Xs) ).
 
+:- meta_predicate tmember_t(1, ?).
+
 tmember_t(P_2, [X|Xs], T) :-
    if_( call(P_2, X), T = true, tmember_t(P_2, Xs, T) ).
diff --git a/src/loader.pl b/src/loader.pl
index b16150c6..06fe2ef2 100644
--- a/src/loader.pl
+++ b/src/loader.pl
@@ -423,7 +423,7 @@ expand_module_names(Goals, MetaSpecs, Module, ExpandedGoals, HeadVars) :-
     Goals =.. [GoalFunctor | SubGoals],
     (  GoalFunctor == (:),
        SubGoals = [M, SubGoal] ->
-       expand_module_names(SubGoal, MetaSpecs, Module, ExpandedSubGoal, HeadVars),
+       expand_module_names(SubGoal, MetaSpecs, M, ExpandedSubGoal, HeadVars),
        ExpandedGoals = M:ExpandedSubGoal
     ;  expand_meta_predicate_subgoals(SubGoals, MetaSpecs, Module, ExpandedGoalList, HeadVars),
        ExpandedGoals =.. [GoalFunctor | ExpandedGoalList]
@@ -434,6 +434,28 @@ expand_goal(UnexpandedGoals, Module, ExpandedGoals) :-
     expand_goal(UnexpandedGoals, Module, ExpandedGoals, []),
     !.
 
+expand_goal_cases((Goal0, Goals0), Module, ExpandedGoals, HeadVars) :-
+    (  expand_goal(Goal0, Module, Goal1, HeadVars) ->
+       expand_goal(Goals0, Module, Goals1, HeadVars),
+       thread_goals(Goal1, ExpandedGoals, Goals1, (','))
+    ;  expand_goal(Goals0, Module, Goals1, HeadVars),
+       ExpandedGoals = (Goal0, Goals1)
+    ).
+expand_goal_cases((Goals0 -> Goals1), Module, ExpandedGoals, HeadVars) :-
+    expand_goal(Goals0, Module, ExpandedGoals0, HeadVars),
+    expand_goal(Goals1, Module, ExpandedGoals1, HeadVars),
+    ExpandedGoals = (ExpandedGoals0 -> ExpandedGoals1).
+expand_goal_cases((Goals0 ; Goals1), Module, ExpandedGoals, HeadVars) :-
+    expand_goal(Goals0, Module, ExpandedGoals0, HeadVars),
+    expand_goal(Goals1, Module, ExpandedGoals1, HeadVars),
+    ExpandedGoals = (ExpandedGoals0 ; ExpandedGoals1).
+expand_goal_cases((\+ Goals0), Module, ExpandedGoals, HeadVars) :-
+    expand_goal(Goals0, Module, Goals1, HeadVars),
+    ExpandedGoals = (\+ Goals1).
+expand_goal_cases((Module:Goals0), _, ExpandedGoals, HeadVars) :-
+    expand_goal(Goals0, Module, Goals1, HeadVars),
+    ExpandedGoals = (Module:Goals1).
+
 expand_goal(UnexpandedGoals, Module, ExpandedGoals, HeadVars) :-
     (  var(UnexpandedGoals) ->
        UnexpandedGoals = ExpandedGoals
@@ -442,24 +464,8 @@ expand_goal(UnexpandedGoals, Module, ExpandedGoals, HeadVars) :-
           goal_expansion(UnexpandedGoals1, user, Goals)
        ;  Goals = UnexpandedGoals1
        ),
-       (  Goals = (Goal0, Goals0) ->
-          (  expand_goal(Goal0, Module, Goal1, HeadVars) ->
-             expand_goal(Goals0, Module, Goals1, HeadVars),
-             thread_goals(Goal1, ExpandedGoals, Goals1, (','))
-          ;  expand_goal(Goals0, Module, Goals1, HeadVars),
-             ExpandedGoals = (Goal0, Goals1)
-          )
-       ;  Goals = (Goals0 -> Goals1) ->
-          expand_goal(Goals0, Module, ExpandedGoals0, HeadVars),
-          expand_goal(Goals1, Module, ExpandedGoals1, HeadVars),
-          ExpandedGoals = (ExpandedGoals0 -> ExpandedGoals1)
-       ;  Goals = (Goals0 ; Goals1) ->
-          expand_goal(Goals0, Module, ExpandedGoals0, HeadVars),
-          expand_goal(Goals1, Module, ExpandedGoals1, HeadVars),
-          ExpandedGoals = (ExpandedGoals0 ; ExpandedGoals1)
-       ;  Goals = (\+ Goals0) ->
-          expand_goal(Goals0, Module, Goals1, HeadVars),
-          ExpandedGoals = (\+ Goals1)
+       (  expand_goal_cases(Goals, Module, ExpandedGoals, HeadVars) ->
+          true
        ;  predicate_property(Module:Goals, meta_predicate(MetaSpecs)) ->
           expand_module_names(Goals, MetaSpecs, Module, ExpandedGoals, HeadVars)
        ;  thread_goals(Goals, ExpandedGoals, (','))
diff --git a/src/machine/compile.rs b/src/machine/compile.rs
index 13ac32c5..2d05ae34 100644
--- a/src/machine/compile.rs
+++ b/src/machine/compile.rs
@@ -1001,22 +1001,22 @@ fn append_compiled_clause(
                     AppendOrPrepend::Append,
                 );
 
-                if lower_bound + 1 == target_pos {
-                    let lower_bound_clause_start = find_inner_choice_instr(
-                        code,
-                        skeleton.clauses[lower_bound].clause_start,
-                        index_loc,
-                    );
+                let target_pos_clause_start = find_inner_choice_instr(
+                    code,
+                    skeleton.clauses[target_pos - 1].clause_start,
+                    index_loc,
+                );
 
+                if lower_bound + 1 == target_pos {
                     set_switch_var_offset(
                         code,
                         index_loc,
-                        lower_bound_clause_start - index_loc,
+                        target_pos_clause_start - index_loc,
                         retraction_info,
                     );
                 }
 
-                skeleton.clauses[target_pos - 1].clause_start
+                target_pos_clause_start // skeleton.clauses[target_pos - 1].clause_start
             }
             _ => {
                 skeleton.clauses[target_pos].opt_arg_index_key += clause_loc;
diff --git a/src/machine/machine_state_impl.rs b/src/machine/machine_state_impl.rs
index 277caa08..1b62431e 100644
--- a/src/machine/machine_state_impl.rs
+++ b/src/machine/machine_state_impl.rs
@@ -162,6 +162,14 @@ impl MachineState {
     }
 
     fn bind_with_occurs_check(&mut self, r: Ref, addr: Addr) {
+        if let Ref::StackCell(..) = r {
+            // local variable optimization -- r cannot occur in the
+            // data structure bound to addr, so don't bother
+            // traversing it.
+            self.bind(r, addr);
+            return;
+        }
+
         let mut fail = false;
 
         for addr in self.acyclic_pre_order_iter(addr) {