[Typechecker] Fix a few regressions with @autoclosure (#28677)

* [Typechecker] Introduce a new request to check the structure of @autoclosure

* Revert "[Typechecker] Introduce a new request to check the structure of @autoclosure"

This reverts commit 3b1d4308bd3444230bfc7d031f7ccfa3b366a038.

* [Typechecker] Fix a few regressions related to use of @autoclosure

Author: theblixguy

lib/Sema/TypeCheckType.cpp

@@ -2241,33 +2241,9 @@ Type TypeResolver::resolveAttributedType(TypeAttributes &attrs,
           rep = FunctionType::Representation::Swift;
         } else {
           rep = *parsedRep;
-          
-          if (attrs.has(TAK_autoclosure)) {
-            // @convention(c) and @convention(block) are not allowed with an @autoclosure type.
-            if (rep == FunctionType::Representation::CFunctionPointer ||
-                rep == FunctionType::Representation::Block) {
-              diagnose(attrs.getLoc(TAK_convention),
-                       diag::invalid_autoclosure_and_convention_attributes,
-                       attrs.getConventionName());
-              attrs.clearAttribute(TAK_convention);
-            }
-          }
         }
       }
 
-      // @autoclosure is only valid on parameters.
-      if (!isParam && attrs.has(TAK_autoclosure)) {
-        bool isVariadicFunctionParam =
-            options.is(TypeResolverContext::VariadicFunctionInput) &&
-            !options.hasBase(TypeResolverContext::EnumElementDecl);
-
-        diagnose(attrs.getLoc(TAK_autoclosure),
-                 isVariadicFunctionParam ? diag::attr_not_on_variadic_parameters
-                                         : diag::attr_only_on_parameters,
-                 "@autoclosure");
-        attrs.clearAttribute(TAK_autoclosure);
-      }
-
       if (attrs.has(TAK_differentiable) &&
           !Context.LangOpts.EnableExperimentalDifferentiableProgramming) {
         diagnose(attrs.getLoc(TAK_differentiable),
@@ -2287,6 +2263,28 @@ Type TypeResolver::resolveAttributedType(TypeAttributes &attrs,
     }
   }
 
+  // Validate use of @autoclosure
+  if (attrs.has(TAK_autoclosure)) {
+    if (attrs.hasConvention()) {
+      if (attrs.getConventionName() == "c" ||
+          attrs.getConventionName() == "block") {
+        diagnose(attrs.getLoc(TAK_convention),
+                 diag::invalid_autoclosure_and_convention_attributes,
+                 attrs.getConventionName());
+        attrs.clearAttribute(TAK_convention);
+      }
+    } else if (options.is(TypeResolverContext::VariadicFunctionInput) &&
+               !options.hasBase(TypeResolverContext::EnumElementDecl)) {
+      diagnose(attrs.getLoc(TAK_autoclosure),
+               diag::attr_not_on_variadic_parameters, "@autoclosure");
+      attrs.clearAttribute(TAK_autoclosure);
+    } else if (!options.is(TypeResolverContext::FunctionInput)) {
+      diagnose(attrs.getLoc(TAK_autoclosure), diag::attr_only_on_parameters,
+               "@autoclosure");
+      attrs.clearAttribute(TAK_autoclosure);
+    }
+  }
+
   auto instanceOptions = options;
   instanceOptions.setContext(None);
 

test/attr/attr_autoclosure.swift

@@ -281,3 +281,14 @@ func test_autoclosure_with_generic_argument_mismatch() {
 
   foo(S<String>()) // expected-error {{cannot convert value of type 'S<String>' to expected argument type 'S<Int>'}}
 }
+
+// SR-11934
+func sr_11934(_ x: @autoclosure String...) {} // expected-error {{'@autoclosure' must not be used on variadic parameters}}
+
+// SR-11938
+let sr_11938_1: Array<@autoclosure String> = [] // expected-error {{'@autoclosure' may only be used on parameters}}
+func sr_11938_2() -> @autoclosure String { "" } // expected-error {{'@autoclosure' may only be used on parameters}}
+func sr_11938_3(_ x: [@autoclosure String]) {} // expected-error {{'@autoclosure' may only be used on parameters}}
+
+protocol SR_11938_P {}
+struct SR_11938_S : @autoclosure SR_11938_P {} // expected-error {{'@autoclosure' may only be used on parameters}}