AST: Adopt availability constraints query in AvailabilityContext.

Call `swift::getAvailabilityConstraintsForDecl()` to gather the constraints
that should be added to an AvailabilityContext when constraining it to the
availability of a given declaration.

Author: tshortli

include/swift/AST/AvailabilityContextStorage.h

@@ -23,6 +23,8 @@
 
 namespace swift {
 
+class DeclAvailabilityConstraints;
+
 /// Summarizes availability the constraints contained by an AvailabilityContext.
 class AvailabilityContext::Info {
 public:
@@ -41,9 +43,11 @@ class AvailabilityContext::Info {
   /// of adding this constraint.
   bool constrainWith(const Info &other);
 
-  /// Updates each field to reflect the availability of `decl`, if that
-  /// availability is more restrictive. Returns true if any field was updated.
-  bool constrainWith(const Decl *decl);
+  /// Constrains each field using the given constraints if they are more
+  /// restrictive than the current values. Returns true if any field was
+  /// updated.
+  bool constrainWith(const DeclAvailabilityConstraints &constraints,
+                     ASTContext &ctx);
 
   bool constrainUnavailability(std::optional<AvailabilityDomain> domain);
 

lib/AST/AvailabilityContext.cpp

@@ -12,6 +12,7 @@
 
 #include "swift/AST/AvailabilityContext.h"
 #include "swift/AST/ASTContext.h"
+#include "swift/AST/AvailabilityConstraint.h"
 #include "swift/AST/AvailabilityContextStorage.h"
 #include "swift/AST/AvailabilityInference.h"
 #include "swift/AST/Decl.h"
@@ -63,16 +64,27 @@ bool AvailabilityContext::Info::constrainWith(const Info &other) {
   return isConstrained;
 }
 
-bool AvailabilityContext::Info::constrainWith(const Decl *decl) {
+bool AvailabilityContext::Info::constrainWith(
+    const DeclAvailabilityConstraints &constraints, ASTContext &ctx) {
   bool isConstrained = false;
 
-  if (auto range = AvailabilityInference::annotatedAvailableRange(decl))
-    isConstrained |= constrainRange(Range, *range);
-
-  if (auto attr = decl->getUnavailableAttr())
-    isConstrained |= constrainUnavailability(attr->getDomain());
-
-  isConstrained |= CONSTRAIN_BOOL(IsDeprecated, decl->isDeprecated());
+  for (auto constraint : constraints) {
+    auto attr = constraint.getAttr();
+    auto domain = attr.getDomain();
+    switch (constraint.getKind()) {
+    case AvailabilityConstraint::Kind::AlwaysUnavailable:
+    case AvailabilityConstraint::Kind::Obsoleted:
+    case AvailabilityConstraint::Kind::RequiresVersion:
+      isConstrained |= constrainUnavailability(domain);
+      break;
+    case AvailabilityConstraint::Kind::IntroducedInNewerVersion:
+      // FIXME: [availability] Support versioning for other kinds of domains.
+      DEBUG_ASSERT(domain.isPlatform());
+      if (domain.isPlatform())
+        isConstrained |= constrainRange(Range, attr.getIntroducedRange(ctx));
+      break;
+    }
+  }
 
   return isConstrained;
 }
@@ -190,7 +202,9 @@ void AvailabilityContext::constrainWithDeclAndPlatformRange(
   bool isConstrained = false;
 
   Info info{storage->info};
-  isConstrained |= info.constrainWith(decl);
+  auto constraints = swift::getAvailabilityConstraintsForDecl(decl, *this);
+  isConstrained |= info.constrainWith(constraints, decl->getASTContext());
+  isConstrained |= CONSTRAIN_BOOL(info.IsDeprecated, decl->isDeprecated());
   isConstrained |= constrainRange(info.Range, platformRange);
 
   if (!isConstrained)