Merge pull request #13259 from rudkx/do-not-decay-iuo-to-optional

For Swift 3/4 mode, do not treat IUOs in illegal positions as Optionals.

Author: shahmishal

include/swift/AST/DiagnosticsSema.def

@@ -3117,11 +3117,11 @@ WARNING(implicitly_unwrapped_optional_spelling_deprecated,none,
 WARNING(implicitly_unwrapped_optional_spelling_deprecated_with_fixit,none,
         "the spelling 'ImplicitlyUnwrappedOptional' is deprecated; use '!' after the type name", ())
 
-WARNING(implicitly_unwrapped_optional_spelling_decay_to_optional,none,
-        "'ImplicitlyUnwrappedOptional' is not allowed here; interpreting this as 'Optional' instead", ())
+WARNING(implicitly_unwrapped_optional_spelling_suggest_optional,none,
+        "using 'ImplicitlyUnwrappedOptional' in this location is deprecated and will be removed in a future release; consider changing this to 'Optional' instead", ())
 
-WARNING(implicitly_unwrapped_optional_in_illegal_position_decay_to_optional,none,
-        "'!' is not allowed here; interpreting this as '?' instead", ())
+WARNING(implicitly_unwrapped_optional_in_illegal_position_suggest_optional,none,
+        "using '!' in this location is deprecated and will be removed in a future release; consider changing this to '?' instead", ())
 
 ERROR(implicitly_unwrapped_optional_spelling_error,none,
         "the spelling 'ImplicitlyUnwrappedOptional' is unsupported; use an explicit type followed by '!'", ())

lib/Sema/TypeCheckType.cpp

@@ -1130,14 +1130,6 @@ resolveTopLevelIdentTypeComponent(TypeChecker &TC, DeclContext *DC,
 
   auto id = comp->getIdentifier();
 
-  // If we're compiling for Swift version < 5 and we have a mention of
-  // ImplicitlyUnwrappedOptional where it is not allowed, treat it as
-  // if it was spelled Optional.
-  if (id == TC.Context.Id_ImplicitlyUnwrappedOptional
-      && !options.contains(TypeResolutionFlags::AllowIUO)
-      && !TC.Context.isSwiftVersionAtLeast(5))
-    id = TC.Context.Id_Optional;
-
   NameLookupOptions lookupOptions = defaultUnqualifiedLookupOptions;
   if (options.contains(TypeResolutionFlags::KnownNonCascadingDependency))
     lookupOptions |= NameLookupFlags::KnownPrivate;
@@ -1239,7 +1231,7 @@ resolveTopLevelIdentTypeComponent(TypeChecker &TC, DeclContext *DC,
       }
     } else if (isa<GenericIdentTypeRepr>(comp)) {
       Diagnostic diag =
-          diag::implicitly_unwrapped_optional_spelling_decay_to_optional;
+          diag::implicitly_unwrapped_optional_spelling_suggest_optional;
 
       if (TC.Context.isSwiftVersionAtLeast(5))
         diag = diag::implicitly_unwrapped_optional_spelling_in_illegal_position;
@@ -1258,7 +1250,7 @@ resolveTopLevelIdentTypeComponent(TypeChecker &TC, DeclContext *DC,
               genericTyR->getAngleBrackets().End.getAdvancedLoc(1));
     } else {
       Diagnostic diag =
-          diag::implicitly_unwrapped_optional_spelling_decay_to_optional;
+          diag::implicitly_unwrapped_optional_spelling_suggest_optional;
 
       if (TC.Context.isSwiftVersionAtLeast(5))
         diag = diag::
@@ -2847,7 +2839,7 @@ Type TypeResolver::resolveImplicitlyUnwrappedOptionalType(
        TypeResolutionOptions options) {
   if (!options.contains(TypeResolutionFlags::AllowIUO)) {
     Diagnostic diag = diag::
-        implicitly_unwrapped_optional_in_illegal_position_decay_to_optional;
+        implicitly_unwrapped_optional_in_illegal_position_suggest_optional;
 
     if (TC.Context.isSwiftVersionAtLeast(5))
       diag = diag::implicitly_unwrapped_optional_in_illegal_position;
@@ -2865,12 +2857,8 @@ Type TypeResolver::resolveImplicitlyUnwrappedOptionalType(
   if (!baseTy || baseTy->hasError()) return baseTy;
 
   Type uncheckedOptionalTy;
-  if (!options.contains(TypeResolutionFlags::AllowIUO))
-    // Treat IUOs in illegal positions as optionals.
-    uncheckedOptionalTy = TC.getOptionalType(repr->getExclamationLoc(), baseTy);
-  else
-    uncheckedOptionalTy = TC.getImplicitlyUnwrappedOptionalType(
-        repr->getExclamationLoc(), baseTy);
+  uncheckedOptionalTy =
+      TC.getImplicitlyUnwrappedOptionalType(repr->getExclamationLoc(), baseTy);
 
   if (!uncheckedOptionalTy)
     return ErrorType::get(Context);

test/Migrator/Inputs/API.json

@@ -319,7 +319,7 @@
     "NodeKind": "Function",
     "NodeAnnotation": "WrapOptional",
     "ChildIndex": "1",
-    "LeftUsr": "s:6Cities05ExtraA0P6blibliySSSgAE_SStc1x_tF",
+    "LeftUsr": "s:6Cities05ExtraA0P6blibliySQySSGSSSg_SStc1x_tF",
     "LeftComment": "",
     "RightUsr": "",
     "RightComment": "",
@@ -330,7 +330,7 @@
     "NodeKind": "Function",
     "NodeAnnotation": "WrapOptional",
     "ChildIndex": "1",
-    "LeftUsr": "s:6Cities05ExtraA0P6blibliySSSgAE_SStc1x_tF",
+    "LeftUsr": "s:6Cities05ExtraA0P6blibliySQySSGSSSg_SStc1x_tF",
     "LeftComment": "",
     "RightUsr": "",
     "RightComment": "",
@@ -341,7 +341,7 @@
     "NodeKind": "Function",
     "NodeAnnotation": "WrapOptional",
     "ChildIndex": "1",
-    "LeftUsr": "s:6Cities05ExtraA0P6blibliySSSgAE_SStc1x_tF",
+    "LeftUsr": "s:6Cities05ExtraA0P6blibliySQySSGSSSg_SStc1x_tF",
     "LeftComment": "",
     "RightUsr": "",
     "RightComment": "",
@@ -352,7 +352,7 @@
     "NodeKind": "Function",
     "NodeAnnotation": "ImplicitOptionalToOptional",
     "ChildIndex": "1:0",
-    "LeftUsr": "s:6Cities05ExtraA0P6blibliySSSgAE_SStc1x_tF",
+    "LeftUsr": "s:6Cities05ExtraA0P6blibliySQySSGSSSg_SStc1x_tF",
     "LeftComment": "",
     "RightUsr": "",
     "RightComment": "",
@@ -363,7 +363,7 @@
     "NodeKind": "Function",
     "NodeAnnotation": "UnwrapOptional",
     "ChildIndex": "1:1:0",
-    "LeftUsr": "s:6Cities05ExtraA0P6blibliySSSgAE_SStc1x_tF",
+    "LeftUsr": "s:6Cities05ExtraA0P6blibliySQySSGSSSg_SStc1x_tF",
     "LeftComment": "",
     "RightUsr": "",
     "RightComment": "",