Merge pull request #63851 from angela-laar/fix-existential-parameterized-protocol-diagnostic

Fix existential parameterized protocol diagnostic

Author: angela-laar

lib/Sema/TypeCheckType.cpp

@@ -758,14 +758,32 @@ static Type applyGenericArguments(Type type, TypeResolution resolution,
     }
 
     // Build ParameterizedProtocolType if the protocol has a primary associated
-    // type and we're in a supported context (for now just generic requirements,
-    // inheritance clause, extension binding).
+    // type and we're in a supported context.
     if (resolution.getOptions().isConstraintImplicitExistential() &&
         !ctx.LangOpts.hasFeature(Feature::ImplicitSome)) {
-      diags.diagnose(loc, diag::existential_requires_any,
-                     protoDecl->getDeclaredInterfaceType(),
-                     protoDecl->getDeclaredExistentialType(),
-                     /*isAlias=*/isa<TypeAliasType>(type.getPointer()));
+
+      if (!genericArgs.empty()) {
+
+        SmallVector<Type, 2> argTys;
+        for (auto *genericArg : genericArgs) {
+          Type argTy = resolution.resolveType(genericArg);
+          if (!argTy || argTy->hasError())
+            return ErrorType::get(ctx);
+
+          argTys.push_back(argTy);
+        }
+
+        auto parameterized =
+            ParameterizedProtocolType::get(ctx, protoType, argTys);
+        diags.diagnose(loc, diag::existential_requires_any, parameterized,
+                       ExistentialType::get(parameterized),
+                       /*isAlias=*/isa<TypeAliasType>(type.getPointer()));
+      } else {
+        diags.diagnose(loc, diag::existential_requires_any,
+                       protoDecl->getDeclaredInterfaceType(),
+                       protoDecl->getDeclaredExistentialType(),
+                       /*isAlias=*/isa<TypeAliasType>(type.getPointer()));
+      }
 
       return ErrorType::get(ctx);
     }

test/type/explicit_existential_swift6.swift

@@ -145,10 +145,16 @@ protocol Collection<T> {
   associatedtype T
 }
 
+struct TestParameterizedProtocol<T> : Collection {
+  typealias T = T
+
+  let x : Collection<T> // expected-error {{use of protocol 'Collection<T>' as a type must be written 'any Collection<T>'}}
+}
+
 func acceptAny(_: Collection<Int>) {}
-// expected-error@-1 {{use of protocol 'Collection' as a type must be written 'any Collection'}}
+// expected-error@-1 {{use of protocol 'Collection<Int>' as a type must be written 'any Collection<Int>'}}
 func returnsAny() -> Collection<Int> {}
-// expected-error@-1 {{use of protocol 'Collection' as a type must be written 'any Collection'}}
+// expected-error@-1 {{use of protocol 'Collection<Int>' as a type must be written 'any Collection<Int>'}}
 
 func testInvalidAny() {
   struct S: HasAssoc {

test/type/parameterized_existential.swift

@@ -7,10 +7,10 @@ protocol Sequence<Element> { // expected-note {{'Sequence' declared here}}
 // 'any' is required here
 
 func takesSequenceOfInt1(_: Sequence<Int>) {}
-// expected-error@-1 {{use of protocol 'Sequence' as a type must be written 'any Sequence'}}
+// expected-error@-1 {{use of protocol 'Sequence<Int>' as a type must be written 'any Sequence<Int>'}}
 
 func returnsSequenceOfInt1() -> Sequence<Int> {}
-// expected-error@-1 {{use of protocol 'Sequence' as a type must be written 'any Sequence'}}
+// expected-error@-1 {{use of protocol 'Sequence<Int>' as a type must be written 'any Sequence<Int>'}}
 
 struct ConcreteSequence<Element> : Sequence {}
 
@@ -74,7 +74,7 @@ func saturation(_ dry: any Sponge, _ wet: any Sponge<Int, Int>) {
 
 func typeExpr() {
   _ = Sequence<Int>.self
-  // expected-error@-1 {{use of protocol 'Sequence' as a type must be written 'any Sequence'}}
+  // expected-error@-1 {{use of protocol 'Sequence<Int>' as a type must be written 'any Sequence<Int>'}}
 
   _ = any Sequence<Int>.self
   // expected-error@-1 {{'self' is not a member type of protocol 'parameterized_existential.Sequence<Swift.Int>'}}