[AST] Promote isNoImplicitCopy to Decl.

Move the predicate up from ParamDecl to Decl and use it everywhere in
place of hasAttribute<NoImplicitCopyAttr>.

Author: nate-chandler

include/swift/AST/Decl.h

@@ -986,6 +986,10 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   /// Check if this is a declaration defined at the top level of the Swift module
   bool isStdlibDecl() const;
 
+  bool isNoImplicitCopy() const {
+    return getAttrs().hasAttribute<NoImplicitCopyAttr>();
+  }
+
   AvailabilityContext getAvailabilityForLinkage() const;
 
   /// Whether this declaration or one of its outer contexts has the
@@ -5783,10 +5787,6 @@ class ParamDecl : public VarDecl {
     setDefaultArgumentKind(K.argumentKind);
   }
 
-  bool isNoImplicitCopy() const {
-    return getAttrs().hasAttribute<NoImplicitCopyAttr>();
-  }
-
   /// Whether this parameter has a default argument expression available.
   ///
   /// Note that this will return false for deserialized declarations, which only

lib/AST/ASTDumper.cpp

@@ -979,7 +979,7 @@ namespace {
         break;
       }
 
-      if (P->getAttrs().hasAttribute<NoImplicitCopyAttr>())
+      if (P->isNoImplicitCopy())
         OS << " noImplicitCopy";
 
       if (P->getDefaultArgumentKind() != DefaultArgumentKind::None) {

lib/SILGen/SILGenDecl.cpp

@@ -450,7 +450,7 @@ class LetValueInitialization : public Initialization {
   LetValueInitialization(VarDecl *vd, SILGenFunction &SGF) : vd(vd) {
     const TypeLowering *lowering = nullptr;
     if (SGF.getASTContext().LangOpts.Features.count(Feature::MoveOnly) &&
-        vd->getAttrs().hasAttribute<NoImplicitCopyAttr>()) {
+        vd->isNoImplicitCopy()) {
       lowering = &SGF.getTypeLowering(
           SILMoveOnlyWrappedType::get(vd->getType()->getCanonicalType()));
     } else {
@@ -487,8 +487,7 @@ class LetValueInitialization : public Initialization {
     // Make sure that we have a non-address only type when binding a
     // @_noImplicitCopy let.
     if (SGF.getASTContext().LangOpts.Features.count(Feature::MoveOnly) &&
-        lowering->isAddressOnly() &&
-        vd->getAttrs().hasAttribute<NoImplicitCopyAttr>()) {
+        lowering->isAddressOnly() && vd->isNoImplicitCopy()) {
       auto d = diag::noimplicitcopy_used_on_generic_or_existential;
       diagnose(SGF.getASTContext(), vd->getLoc(), d);
     }
@@ -569,8 +568,7 @@ class LetValueInitialization : public Initialization {
       // ... and we don't have a no implicit copy trivial type, just return
       // value.
       if (!SGF.getASTContext().LangOpts.Features.count(Feature::MoveOnly) ||
-          !vd->getAttrs().hasAttribute<NoImplicitCopyAttr>() ||
-          !value->getType().isTrivial(SGF.F))
+          !vd->isNoImplicitCopy() || !value->getType().isTrivial(SGF.F))
         return value;
 
       // Otherwise, we have a no implicit copy trivial type, so wrap it in the
@@ -626,7 +624,7 @@ class LetValueInitialization : public Initialization {
 
     // Otherwise, if we do not have a no implicit copy variable, just follow
     // the "normal path": perform a lexical borrow if the lifetime is lexical.
-    if (!vd->getAttrs().hasAttribute<NoImplicitCopyAttr>()) {
+    if (!vd->isNoImplicitCopy()) {
       if (SGF.F.getLifetime(vd, value->getType()).isLexical())
         return SGF.B.createBeginBorrow(PrologueLoc, value, /*isLexical*/ true);
       else