Merge pull request #40266 from hamishknight/hoping-for-closure

Author: hamishknight

lib/Sema/MiscDiagnostics.cpp

@@ -3509,6 +3509,13 @@ static void checkStmtConditionTrailingClosure(ASTContext &ctx, const Expr *E) {
 
     bool shouldWalkIntoTapExpression() override { return false; }
 
+    std::pair<bool, ArgumentList *>
+    walkToArgumentListPre(ArgumentList *args) override {
+      // Don't walk into an explicit argument list, as trailing closures that
+      // appear in child arguments are fine.
+      return {args->isImplicit(), args};
+    }
+
     std::pair<bool, Expr *> walkToExprPre(Expr *E) override {
       switch (E->getKind()) {
       case ExprKind::Paren:

test/expr/closure/trailing.swift

@@ -466,3 +466,12 @@ class TrailingDerived : TrailingBase {
     super.init(x: x) {}
   }
 }
+
+// rdar://85343171 - Spurious warning on trailing closure in argument list.
+func rdar85343171() {
+  func foo(_ i: Int) -> Bool { true }
+  func bar(_ fn: () -> Void) -> Int { 0 }
+
+  // Okay, as trailing closure is nested in argument list.
+  if foo(bar {}) {}
+}