[AST] ApplyExpr: Rename shouldApplyDistributedThunk to usesDistributedThunk

Since the thunk is applied to expression during solution application,
the use of this flag has shifted towards stating the fact.

Author: xedin

include/swift/AST/Expr.h

@@ -319,7 +319,7 @@ class alignas(8) Expr : public ASTAllocated<Expr> {
     ImplicitlyAsync : 1,
     ImplicitlyThrows : 1,
     NoAsync : 1,
-    ShouldApplyDistributedThunk : 1
+    UsesDistributedThunk : 1
   );
 
   SWIFT_INLINE_BITFIELD_EMPTY(CallExpr, ApplyExpr);
@@ -4445,7 +4445,7 @@ class ApplyExpr : public Expr {
     Bits.ApplyExpr.ImplicitlyAsync = false;
     Bits.ApplyExpr.ImplicitlyThrows = false;
     Bits.ApplyExpr.NoAsync = false;
-    Bits.ApplyExpr.ShouldApplyDistributedThunk = false;
+    Bits.ApplyExpr.UsesDistributedThunk = false;
   }
 
 public:
@@ -4532,11 +4532,11 @@ class ApplyExpr : public Expr {
 
   /// Informs IRGen to that this expression should be applied as its distributed
   /// thunk, rather than invoking the function directly.
-  bool shouldApplyDistributedThunk() const {
-    return Bits.ApplyExpr.ShouldApplyDistributedThunk;
+  bool usesDistributedThunk() const {
+    return Bits.ApplyExpr.UsesDistributedThunk;
   }
-  void setShouldApplyDistributedThunk(bool flag) {
-    Bits.ApplyExpr.ShouldApplyDistributedThunk = flag;
+  void setUsesDistributedThunk(bool flag) {
+    Bits.ApplyExpr.UsesDistributedThunk = flag;
   }
 
   ValueDecl *getCalledValue() const;

lib/SILGen/SILGenApply.cpp

@@ -1125,7 +1125,7 @@ class SILGenApply : public Lowering::ExprVisitor<SILGenApply> {
     SILDeclRef constant = SILDeclRef(e->getDecl());
 
     /// Some special handling may be necessary for thunks:
-    if (callSite && callSite->shouldApplyDistributedThunk()) {
+    if (callSite && callSite->usesDistributedThunk()) {
       constant = SILDeclRef(e->getDecl()).asDistributed();
     } else if (afd->isBackDeployed()) {
       // If we're calling a back deployed function then we need to call a

lib/Sema/CSApply.cpp

@@ -1670,7 +1670,7 @@ namespace {
         if (isa<VarDecl>(decl)) {
           auto *thunkCall = CallExpr::createImplicitEmpty(context, thunkApply);
           thunkCall->setType(solution.simplifyType(openedType));
-          thunkCall->setShouldApplyDistributedThunk(true);
+          thunkCall->setUsesDistributedThunk(true);
           cs.cacheType(thunkCall);
           return thunkCall;
         }
@@ -7797,7 +7797,7 @@ Expr *ExprRewriter::finishApply(ApplyExpr *apply, Type openedType,
         apply->setImplicitlyThrows(true);
       if (!FD->hasAsync())
         apply->setImplicitlyAsync(ImplicitActorHopTarget::forInstanceSelf());
-      apply->setShouldApplyDistributedThunk(true);
+      apply->setUsesDistributedThunk(true);
     }
 
     solution.setExprTypes(apply);

lib/Sema/TypeCheckConcurrency.cpp

@@ -1779,7 +1779,7 @@ namespace {
             call->setImplicitlyThrows(false);
           }
           if (setDistributedThunk) {
-            call->setShouldApplyDistributedThunk(true);
+            call->setUsesDistributedThunk(true);
           }
           return;
         }