[CSDiagnostics] Update test cases for variadic generic functions

Author: li3zhen1

lib/Sema/CSDiagnostics.cpp

@@ -8203,19 +8203,18 @@ bool UnableToInferGenericPackElementType::diagnoseAsError() {
   auto *locator = getLocator();
   auto path = locator->getPath();
 
-  const auto applyArgToParamElt =
-      (path.end() - 2)->getAs<LocatorPathElt::ApplyArgToParam>();
-  const auto packElementElt =
-      (path.end() - 1)->getAs<LocatorPathElt::PackElement>();
-  if (!applyArgToParamElt || !packElementElt) {
-    return false;
-  }
+  auto packElementElt = (path.end() - 1)->getAs<LocatorPathElt::PackElement>();
+  assert(packElementElt && "Expected path to end with a pack element locator");
 
   if (isExpr<NilLiteralExpr>(getAnchor())) {
     // `nil` appears as an element of generic pack params, let's record a
     // specify contextual type for nil fix.
     emitDiagnostic(diag::unresolved_nil_literal);
   } else {
+    if (llvm::any_of(getSolution().Fixes, [&locator](const ConstraintFix *fix) {
+          return fix->getLocator() == locator;
+        }))
+      return false;
     // unable to infer the type of an element of generic pack params
     emitDiagnostic(diag::could_not_infer_pack_element,
                    packElementElt->getIndex());
@@ -8226,6 +8225,8 @@ bool UnableToInferGenericPackElementType::diagnoseAsError() {
     if (auto *calleeLocator = getSolution().getCalleeLocator(locator)) {
       if (const auto choice = getOverloadChoiceIfAvailable(calleeLocator)) {
         if (auto *decl = choice->choice.getDeclOrNull()) {
+          const auto applyArgToParamElt =
+              (path.end() - 2)->getAs<LocatorPathElt::ApplyArgToParam>();
           if (auto paramDecl =
                   getParameterAt(decl, applyArgToParamElt->getParamIdx())) {
             emitDiagnosticAt(

test/Constraints/variadic_generic_functions.swift

@@ -1,4 +1,4 @@
-// RUN: %target-typecheck-verify-swift
+// RUN: %target-typecheck-verify-swift -disable-availability-checking
 
 func debugPrint<each T>(_ items: repeat each T)
   where repeat each T: CustomDebugStringConvertible
@@ -83,25 +83,33 @@ do {
 
 // apple/swift#69432 - Passing nil to a parameter pack fails to produce diagnostic for expression
 do {
-  func foo<each T>(_ value: repeat each T) {} // expected-note {{in inferring pack element #1 of 'value'}}
-  // expected-note@-1 {{in inferring pack element #1 of 'value'}}
-  // expected-note@-2 {{in inferring pack element #2 of 'value'}}
+  func foo<each T>(_ value: repeat each T) {} // expected-note {{in inferring pack element #0 of 'value'}}
+  // expected-note@-1 {{in inferring pack element #0 of 'value'}}
+  // expected-note@-2 {{in inferring pack element #1 of 'value'}}
 
   foo(nil) // expected-error {{'nil' requires a contextual type}}
   foo(nil, 1) // expected-error {{'nil' requires a contextual type}}
   foo(2, nil) // expected-error {{'nil' requires a contextual type}}
 
-  func bar<each T, U, each W>(_ t: repeat each T, u: U, w: repeat each W) {} // expected-note {{in inferring pack element #3 of 'w'}}
-  // expected-note@-1 {{in inferring pack element #4 of 't'}}
+  func bar<each T, U, each W>(_ t: repeat each T, u: U, w: repeat each W) {} // expected-note {{in inferring pack element #2 of 'w'}}
+  // expected-note@-1 {{in inferring pack element #3 of 't'}}
 
   bar(1, 2, 3, nil, "Hello", u: 3, w: 4, 8, nil) // expected-error {{'nil' requires a contextual type}}
   // expected-error@-1 {{'nil' requires a contextual type}}
 
 
   func fooWithOverload(_ value: Int) {}
   func fooWithOverload<each T>(_ value: repeat each T) {}
-  // expected-note@-1 {{in inferring pack element #5 of 'value'}}
+  // expected-note@-1 {{in inferring pack element #4 of 'value'}}
 
   fooWithOverload(0, 1, 2, 3, nil) // expected-error {{'nil' requires a contextual type}}
 
+  struct Foo<each T> {
+    init(_ value: repeat each T) {}
+    // expected-note@-1 {{in inferring pack element #0 of 'value'}}
+    // expected-note@-2 {{in inferring pack element #0 of 'value'}}
+  }
+
+  _ = Foo(nil) // expected-error {{'nil' requires a contextual type}}
+  _ = Foo(nil, 1) // expected-error {{'nil' requires a contextual type}}
 }