Merge pull request #30757 from slavapestov/fix-function-builder-autoclosure-crash

Sema: Contextualize closures for function builder bodies also

Author: slavapestov

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -812,7 +812,7 @@ Expr *DefaultArgumentExprRequest::evaluate(Evaluator &evaluator,
 
   // Walk the checked initializer and contextualize any closures
   // we saw there.
-  (void)TypeChecker::contextualizeInitializer(dc, initExpr);
+  TypeChecker::contextualizeInitializer(dc, initExpr);
   return initExpr;
 }
 
@@ -1582,7 +1582,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
           if (initContext) {
             // Check safety of error-handling in the declaration, too.
             TypeChecker::checkInitializerErrorHandling(initContext, init);
-            (void)TypeChecker::contextualizeInitializer(initContext, init);
+            TypeChecker::contextualizeInitializer(initContext, init);
           }
         }
       }

lib/Sema/TypeCheckStmt.cpp

@@ -84,10 +84,6 @@ namespace {
                           unsigned nextDiscriminator = 0)
       : ParentDC(parent), NextDiscriminator(nextDiscriminator) {}
 
-    bool hasAutoClosures() const {
-      return NextDiscriminator != 0;
-    }
-
     std::pair<bool, Expr *> walkToExprPre(Expr *E) override {
       // Autoclosures need to be numbered and potentially reparented.
       // Reparenting is required with:
@@ -228,14 +224,9 @@ namespace {
   };
 } // end anonymous namespace
 
-static void setAutoClosureDiscriminators(DeclContext *DC, Stmt *S) {
-  S->walk(ContextualizeClosures(DC));
-}
-
-bool TypeChecker::contextualizeInitializer(Initializer *DC, Expr *E) {
+void TypeChecker::contextualizeInitializer(Initializer *DC, Expr *E) {
   ContextualizeClosures CC(DC);
   E->walk(CC);
-  return CC.hasAutoClosures();
 }
 
 void TypeChecker::contextualizeTopLevelCode(TopLevelCodeDecl *TLCD) {
@@ -422,7 +413,7 @@ class StmtChecker : public StmtVisitor<StmtChecker, Stmt*> {
   /// Type-check an entire function body.
   bool typeCheckBody(BraceStmt *&S) {
     bool HadError = typeCheckStmt(S);
-    setAutoClosureDiscriminators(DC, S);
+    S->walk(ContextualizeClosures(DC));
     return HadError;
   }
 
@@ -1920,6 +1911,8 @@ TypeCheckFunctionBodyUntilRequest::evaluate(Evaluator &evaluator,
 
         body = *optBody;
         alreadyTypeChecked = true;
+
+        body->walk(ContextualizeClosures(AFD));
       }
     } else if (func->hasSingleExpressionBody() &&
                func->getResultInterfaceType()->isVoid()) {

lib/Sema/TypeChecker.h

@@ -935,9 +935,7 @@ void checkPatternBindingCaptures(IterableDeclContext *DC);
 
 /// Change the context of closures in the given initializer
 /// expression to the given context.
-///
-/// \returns true if any closures were found
-bool contextualizeInitializer(Initializer *DC, Expr *init);
+void contextualizeInitializer(Initializer *DC, Expr *init);
 void contextualizeTopLevelCode(TopLevelCodeDecl *TLCD);
 
 /// Retrieve the default type for the given protocol.

test/SILGen/function_builder_curry_thunks.swift

@@ -0,0 +1,33 @@
+// RUN: %target-swift-emit-silgen %s | %FileCheck %s
+
+@_functionBuilder
+struct Builder {
+  static func buildBlock<T1>(_ t1: T1) -> (T1) {
+    return (t1)
+  }
+}
+
+struct Handler {
+  var firstHandler: () -> ()
+  var secondHandler: () -> ()
+}
+
+// We were neglecting to assign discriminators and re-parent
+// autoclosures, which would manifest as curried method references
+// producing a bogus diagnostic about captures from inside a
+// nested type.
+class Outer {
+  struct Inner {
+    @Builder
+    var build: Handler {
+      Handler(firstHandler: self.handler, secondHandler: self.handler)
+    }
+
+    private func handler() {}
+  }
+}
+
+// CHECK-LABEL: sil private [ossa] @$s29function_builder_curry_thunks5OuterC5InnerV5buildAA7HandlerVvgyycAEcfu_ : $@convention(thin) (Outer.Inner) -> @owned @callee_guaranteed () -> ()
+// CHECK-LABEL: sil private [ossa] @$s29function_builder_curry_thunks5OuterC5InnerV5buildAA7HandlerVvgyycAEcfu_yycfu0_ : $@convention(thin) (Outer.Inner) -> ()
+// CHECK-LABEL: sil private [ossa] @$s29function_builder_curry_thunks5OuterC5InnerV7handler33_DC254A3F89F9C7E65D25434E199F17A4LLyyF : $@convention(method) (Outer.Inner) -> ()
+// CHECK-LABEL: sil private [ossa] @$s29function_builder_curry_thunks5OuterC5InnerV5buildAA7HandlerVvgyycAEcfu1_ : $@convention(thin) (Outer.Inner) -> @owned @callee_guaranteed () -> ()