[ConstraintSystem] Convert Fixes to a set vector to avoid duplicates

Author: xedin

include/swift/Sema/ConstraintSystem.h

@@ -2377,7 +2377,7 @@ class ConstraintSystem {
       ConstraintRestrictions;
 
   /// The set of fixes applied to make the solution work.
-  llvm::SmallVector<ConstraintFix *, 4> Fixes;
+  llvm::SmallSetVector<ConstraintFix *, 4> Fixes;
 
   /// The set of remembered disjunction choices used to reach
   /// the current constraint system.
@@ -3420,7 +3420,7 @@ class ConstraintSystem {
     return !solverState || solverState->recordFixes;
   }
 
-  ArrayRef<ConstraintFix *> getFixes() const { return Fixes; }
+  ArrayRef<ConstraintFix *> getFixes() const { return Fixes.getArrayRef(); }
 
   bool shouldSuppressDiagnostics() const {
     return Options.contains(ConstraintSystemFlags::SuppressDiagnostics);

lib/Sema/CSSimplify.cpp

@@ -11516,7 +11516,7 @@ bool ConstraintSystem::recordFix(ConstraintFix *fix, unsigned impact) {
     return true;
 
   if (isAugmentingFix(fix)) {
-    Fixes.push_back(fix);
+    Fixes.insert(fix);
     return false;
   }
 
@@ -11541,7 +11541,7 @@ bool ConstraintSystem::recordFix(ConstraintFix *fix, unsigned impact) {
   }
 
   if (!found)
-    Fixes.push_back(fix);
+    Fixes.insert(fix);
 
   return false;
 }

lib/Sema/CSSolver.cpp

@@ -309,7 +309,7 @@ void ConstraintSystem::applySolution(const Solution &solution) {
   }
 
   // Register any fixes produced along this path.
-  Fixes.append(solution.Fixes.begin(), solution.Fixes.end());
+  Fixes.insert(solution.Fixes.begin(), solution.Fixes.end());
 }
 
 /// Restore the type variable bindings to what they were before