AST: Desugar typed patterns in swiftinterfaces consistently.

lib/AST/ASTPrinter.cpp

@@ -3926,9 +3926,20 @@ void PrintAST::visitPatternBindingDecl(PatternBindingDecl *decl) {
   for (auto idx : range(decl->getNumPatternEntries())) {
     auto *pattern = decl->getPattern(idx);
 
-    // Force the entry to be typechecked before attempting to print.
-    if (shouldPrintAllSemanticDetails(Options) && !pattern->hasType())
-      (void)decl->getCheckedPatternBindingEntry(idx);
+    if (shouldPrintAllSemanticDetails(Options)) {
+      // Force the entry to be typechecked before attempting to print.
+      if (!pattern->hasType())
+        (void)decl->getCheckedPatternBindingEntry(idx);
+
+      // HACK: If the pattern type is a typealias, trigger a request that will
+      // fully typecheck the init. This ensures typealiases are desguared
+      // consistently.
+      if (decl->isInitialized(idx)) {
+        if (auto type = pattern->getType())
+          if (type->getKind() == TypeKind::TypeAlias)
+            (void)decl->getCheckedAndContextualizedInit(idx);
+      }
+    }
 
     if (!shouldPrintPattern(pattern))
       continue;

test/Inputs/lazy_typecheck.swift

@@ -16,6 +16,10 @@ public func publicFunc() -> Int {
   return NoTypecheck.int
 }
 
+public func publicFuncReturnsTypealias() -> PublicIntAlias {
+  return NoTypecheck.int
+}
+
 public func publicFuncWithDefaultArg(_ x: Int = 1) -> Int {
   return NoTypecheck.int
 }
@@ -88,11 +92,15 @@ struct InternalWrapper {
 // MARK: - Global vars
 
 public var publicGlobalVar: Int = NoTypecheck.int
+public var publicGlobalVarTypealias: PublicIntAlias = 1
 public var publicGlobalVarInferredType = ""
+public var publicGlobalVarInferredInferredGeneric: [_] = [1]
+public var publicGlobalVarTypealiasGeneric: PublicIntAlias? = 1
 public var (publicGlobalVarInferredTuplePatX, publicGlobalVarInferredTuplePatY) = (0, 1)
 
 var internalGlobalVar: NoTypecheck = NoTypecheck()
 var internalGlobalVarInferredType = NoTypecheck()
+var internalGlobalTypealiasVar: PublicIntAlias = NoTypecheck.int
 
 // MARK: - Nominal types
 
@@ -132,6 +140,7 @@ protocol InternalProtoConformingToPublicProto: PublicProto {
 
 public struct PublicStruct {
   public var publicProperty: Int = NoTypecheck.int
+  public var publicTypealiasProperty: PublicIntAlias = 1
   public var publicPropertyInferredType = ""
   public var publicLazyProperty: Int = NoTypecheck.int
   public var publicLazyPropertyInferred = 1
@@ -334,6 +343,7 @@ extension PublicGenericStruct: EmptyPublicProto where T == InternalStructForCons
 
 // MARK: - Type aliases
 
+public typealias PublicIntAlias = Int
 public typealias PublicStructAlias = PublicStruct
 typealias InternalTypeAlias = NoTypecheck
 

test/Inputs/lazy_typecheck_client.swift

@@ -12,30 +12,35 @@ struct ConformsToMainActorProto: MainActorProtocol {
 }
 
 func testGlobalFunctions() {
-  _ = publicFunc()
-  _ = publicFuncWithDefaultArg()
+  let _: Int = publicFunc()
+  let _: Int = publicFuncReturnsTypealias()
+  let _: Int = publicFuncWithDefaultArg()
   #if TEST_PACKAGE
-  _ = packageFunc()
+  let _: Int = packageFunc()
   #endif
   constrainedGenericPublicFunction(ConformsToPublicProto())
-  _ = publicSpecializedFunc(4)
-  _ = publicSpecializedFunc(ConformsToPublicProto())
+  let _: Int = publicSpecializedFunc(4)
+  let _: ConformsToPublicProto = publicSpecializedFunc(ConformsToPublicProto())
   if #available(SwiftStdlib 5.1, *) {
-    _ = publicFuncWithOpaqueReturnType()
-    _ = publicAEICFuncWithOpaqueReturnType()
+    let _: any PublicProto = publicFuncWithOpaqueReturnType()
+    let _: Any = publicAEICFuncWithOpaqueReturnType()
   }
 }
 
 func testGobalVars() {
   let _: Int = publicGlobalVar
+  let _: Int = publicGlobalVarTypealias
   let _: String = publicGlobalVarInferredType
+  let _: [Int] = publicGlobalVarInferredInferredGeneric
+  let _: Int? = publicGlobalVarTypealiasGeneric
   let _: (Int, Int) = (publicGlobalVarInferredTuplePatX, publicGlobalVarInferredTuplePatY)
 }
 
 func testPublicStructs() {
   let s = PublicStruct(x: 1)
   let _: Int = s.publicMethod()
   let _: Int = s.publicProperty
+  let _: Int = s.publicTypealiasProperty
   let _: String = s.publicPropertyInferredType
   let _: Int = s.publicLazyProperty
   let _: Int = s.publicLazyPropertyInferred