refactor(sema): use DenseSet count instead of two loops to enable split constraints

Author: Snowy1803

include/Sema/Constraint.hpp

@@ -460,6 +460,10 @@ class Constraint {
     /// @brief Enable this constraint.
     void enable() { _isDisabled = 0; }
 
+    /// @brief Sets the enabled state of this constraint.
+    /// @param enabled True to enable the constraint, false to disable it.
+    void setEnabled(bool enabled) { _isDisabled = !enabled; }
+
     /// @brief Print this constraint to the output stream.
     void print() const;
 };

include/Sema/ConstraintSystem.hpp

@@ -219,8 +219,11 @@ class ConstraintSystem {
     /// extracted.
     void mapImplicitConversions(Solution *solution);
 
-    /// @brief Solves all constraints and returns the solution result through
-    /// the provided parameter.
+    /// @brief Solves all enabled constraints within this local constraint
+    /// system and returns the solution result through the provided parameter.
+    /// This method is called within solveConstraints, after simplification and
+    /// splitting of the constraint system, and before mapping types back to the
+    /// AST.
     /// @param result The solution result to populate with found solutions.
     /// @return True if a solution was found, false otherwise.
     bool solveLocalConstraints(SolutionResult &result);

lib/Sema/ConstraintSystem/ConstraintSystem.cpp

@@ -298,10 +298,7 @@ bool ConstraintSystem::solveConstraints()
     for (std::size_t i = 0; i < colors.size(); ++i) {
         // Disable all constraints not in this color
         for (auto *constraint : _constraints) {
-            constraint->disable();
-        }
-        for (auto *constraint : colorConstraints[i]) {
-            constraint->enable();
+            constraint->setEnabled(colorConstraints[i].count(constraint));
         }
         SolutionResult result;
         if (!solveLocalConstraints(result)) {