fix(library/util): incorrect hypothesis renaming when pretty printing goals

src/library/util.cpp

@@ -830,24 +830,27 @@ format format_goal(formatter const & fmt, buffer<expr> const & hyps, expr const
     bool compact     = get_pp_compact_goals(opts);
     format turnstile = unicode ? format("\u22A2") /* ⊢ */ : format("|-");
     format r;
-    unsigned i = 0;
-    while (i < hyps.size()) {
-        if (i > 0)
-            r += compose(comma(), line());
+    unsigned i = hyps.size();
+    bool first = true;
+    while (i > 0) {
+        i--;
         expr l     = hyps[i];
         format ids = fmt(l);
         expr t     = tmp_subst.instantiate(mlocal_type(l));
         lean_assert(hyps.size() > 0);
-        while (i < hyps.size() - 1) {
-            expr l2 = hyps[i+1];
+        while (i > 0) {
+            expr l2 = hyps[i-1];
             expr t2 = tmp_subst.instantiate(mlocal_type(l2));
             if (t2 != t)
                 break;
-            ids += space() + fmt(l2);
-            i++;
+            ids = fmt(l2) + space() + ids;
+            i--;
         }
-        r += group(ids + space() + colon() + nest(indent, line() + fmt(t)));
-        i++;
+        if (first)
+            first = false;
+        else
+            r = compose(comma(), line()) + r;
+        r = group(ids + space() + colon() + nest(indent, line() + fmt(t))) + r;
     }
     if (compact)
         r = group(r);

tests/lean/assert_fail.lean.expected.out

@@ -4,8 +4,8 @@ H : b ∧ a
 ⊢ a
 
 a b : Prop,
-H : b ∧ a,
-H_1 : a
+H_1 : b ∧ a,
+H : a
 ⊢ a ∧ b
 assert_fail.lean:4:0: error: failed to add declaration 'example' to environment, value has metavariables
 remark: set 'formatter.hide_full_terms' to false to see the complete term

tests/lean/assert_tac2.lean

@@ -0,0 +1,13 @@
+import data.nat
+open nat
+
+example (a b c : nat) : a = 2 → b = 3 → a + b + c = c + 5 :=
+begin
+  intro h1 h2,
+  have H : a + b = 2 + b, by rewrite h1,
+  have H : a + b = 2 + 3, by rewrite -h2; exact H,
+  have H : a + b = 5, from H,
+  rewrite H,
+  state,
+  rewrite add.comm
+end

tests/lean/assert_tac2.lean.expected.out

@@ -0,0 +1,8 @@
+assert_tac2.lean:11:2: proof state
+a b c : ℕ,
+h1 : a = 2,
+h2 : b = 3,
+H_2 : a + b = 2 + b,
+H_1 : a + b = 2 + 3,
+H : a + b = 5
+⊢ 5 + c = c + 5