[CS] Add SolutionApplicationTarget::isForEachStmt

Author: hamishknight

lib/Sema/ConstraintSystem.h

@@ -1418,6 +1418,12 @@ class SolutionApplicationTarget {
   /// For a pattern initialization target, retrieve the contextual pattern.
   ContextualPattern getContextualPattern() const;
 
+  /// Whether this target is for a for-in statement.
+  bool isForEachStmt() const {
+    return kind == Kind::expression &&
+           getExprContextualTypePurpose() == CTP_ForEachStmt;
+  }
+
   /// Whether this is an initialization for an Optional.Some pattern.
   bool isOptionalSomePatternInit() const {
     return kind == Kind::expression &&
@@ -1466,14 +1472,12 @@ class SolutionApplicationTarget {
   }
 
   const ForEachStmtInfo &getForEachStmtInfo() const {
-    assert(kind == Kind::expression);
-    assert(expression.contextualPurpose == CTP_ForEachStmt);
+    assert(isForEachStmt());
     return expression.forEachStmt;
   }
 
   ForEachStmtInfo &getForEachStmtInfo() {
-    assert(kind == Kind::expression);
-    assert(expression.contextualPurpose == CTP_ForEachStmt);
+    assert(isForEachStmt());
     return expression.forEachStmt;
   }