From 7ef68c3ae120d8fe004e6e981bb706dec958d22d Mon Sep 17 00:00:00 2001
From: Copilot <198982749+Copilot@users.noreply.github.com>
Date: Mon, 27 Jul 2026 07:18:30 -0700
Subject: [PATCH] [nra_solver] Simplify COI guard logic using early-continue
 pattern (#10245)

Refactors the constraint/monic verification loops in `nra_solver.cpp`
introduced by #10230 to reduce nesting and improve readability. No
functional change.

### Changes

- **Early-continue guards**: Replace `if (!check_X(ci)) { if
(coi.contains(ci)) { ... } return l_undef; }` with `if (check_X(ci))
continue;` so the failure path reads linearly
- **Explicit braces**: Add braces to the constraint loop (monic loop
already had them), making both loops consistent
- **Condensed comment**: Collapse 6-line COI explanation to one line

```cpp
// Before
for (lp::constraint_index ci : lra.constraints().indices())
    if (!check_constraint(ci)) {
        // nlsat only solves over the cone-of-influence (COI) subset
        // of constraints, so constraints outside the COI may be
        // legitimately violated by the nlsat model. Only a violation
        // of a COI constraint indicates a genuine nlsat bug; a
        // non-COI violation is benign, so fall back to l_undef
        // quietly without emitting diagnostics.
        if (m_coi.constraints().contains(ci)) { ...; UNREACHABLE(); }
        return l_undef;
    }

// After
for (lp::constraint_index ci : lra.constraints().indices()) {
    if (check_constraint(ci)) continue;
    // Non-COI constraint violations are benign; only COI violations indicate a bug.
    if (m_coi.constraints().contains(ci)) { ...; UNREACHABLE(); }
    return l_undef;
}
```

<!-- START COPILOT CODING AGENT SUFFIX -->

- Fixes #10235

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
---
 src/math/lp/nra_solver.cpp | 36 +++++++++++++++---------------------
 1 file changed, 15 insertions(+), 21 deletions(-)

diff --git a/src/math/lp/nra_solver.cpp b/src/math/lp/nra_solver.cpp
index 8fb383d475..76525520ee 100644
--- a/src/math/lp/nra_solver.cpp
+++ b/src/math/lp/nra_solver.cpp
@@ -238,30 +238,24 @@ struct solver::imp {
             m_nlsat->restore_order();
             m_nla_core.set_use_nra_model(true);
             lra.init_model();
-            for (lp::constraint_index ci : lra.constraints().indices())
-                if (!check_constraint(ci)) {
-                    // nlsat only solves over the cone-of-influence (COI) subset
-                    // of constraints, so constraints outside the COI may be
-                    // legitimately violated by the nlsat model. Only a violation
-                    // of a COI constraint indicates a genuine nlsat bug; a
-                    // non-COI violation is benign, so fall back to l_undef
-                    // quietly without emitting diagnostics.
-                    if (m_coi.constraints().contains(ci)) {
-                        IF_VERBOSE(0, verbose_stream() << "constraint " << ci << " violated\n";
-                                   lra.constraints().display(verbose_stream()));
-                        UNREACHABLE();
-                    }
-                    return l_undef;
+            for (lp::constraint_index ci : lra.constraints().indices()) {
+                if (check_constraint(ci)) continue;
+                // Non-COI constraint violations are benign; only COI violations indicate a bug.
+                if (m_coi.constraints().contains(ci)) {
+                    IF_VERBOSE(0, verbose_stream() << "constraint " << ci << " violated\n";
+                               lra.constraints().display(verbose_stream()));
+                    UNREACHABLE();
                 }
+                return l_undef;
+            }
             for (auto const &m : m_nla_core.emons()) {
-                if (!check_monic(m)) {
-                    if (m_coi.mons().contains(m.var())) {
-                        IF_VERBOSE(0, verbose_stream() << "monic " << m << " violated\n";
-                                   lra.constraints().display(verbose_stream()));
-                        UNREACHABLE();
-                    }
-                    return l_undef;
+                if (check_monic(m)) continue;
+                if (m_coi.mons().contains(m.var())) {
+                    IF_VERBOSE(0, verbose_stream() << "monic " << m << " violated\n";
+                               lra.constraints().display(verbose_stream()));
+                    UNREACHABLE();
                 }
+                return l_undef;
             }
             break;
         case l_false: {