[Type checker] Move capture computation before actor isolation checking.

Actor isolation checking is going to make use of capture information,
so move the computation of captures before both actor isolation checking
and effects checking.

Author: DougGregor

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -910,12 +910,13 @@ Expr *DefaultArgumentExprRequest::evaluate(Evaluator &evaluator,
     return new (ctx) ErrorExpr(initExpr->getSourceRange(), ErrorType::get(ctx));
   }
 
-  checkInitializerActorIsolation(dc, initExpr);
-  TypeChecker::checkInitializerEffects(dc, initExpr);
-
   // Walk the checked initializer and contextualize any closures
   // we saw there.
   TypeChecker::contextualizeInitializer(dc, initExpr);
+
+  checkInitializerActorIsolation(dc, initExpr);
+  TypeChecker::checkInitializerEffects(dc, initExpr);
+
   return initExpr;
 }
 
@@ -1746,10 +1747,9 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
           auto *initContext = cast_or_null<PatternBindingInitializer>(
               PBD->getInitContext(i));
           if (initContext) {
-            // Check safety of error-handling in the declaration, too.
+            TypeChecker::contextualizeInitializer(initContext, init);
             checkInitializerActorIsolation(initContext, init);
             TypeChecker::checkInitializerEffects(initContext, init);
-            TypeChecker::contextualizeInitializer(initContext, init);
           }
         }
       }

lib/Sema/TypeCheckStmt.cpp

@@ -2067,9 +2067,9 @@ TypeCheckFunctionBodyRequest::evaluate(Evaluator &evaluator,
   if (!hadError)
     performAbstractFuncDeclDiagnostics(AFD);
 
+  TypeChecker::computeCaptures(AFD);
   checkFunctionActorIsolation(AFD);
   TypeChecker::checkFunctionEffects(AFD);
-  TypeChecker::computeCaptures(AFD);
 
   return hadError ? errorBody() : body;
 }