Merge pull request #22665 from slavapestov/remove-noreturn

Sema: Remove @NoReturn attribute support

Author: slavapestov

include/swift/AST/Attr.def

@@ -49,7 +49,6 @@
 // Type attributes
 TYPE_ATTR(autoclosure)
 TYPE_ATTR(convention)
-TYPE_ATTR(noreturn)
 TYPE_ATTR(noescape)
 TYPE_ATTR(escaping)
 
@@ -136,9 +135,7 @@ CONTEXTUAL_SIMPLE_DECL_ATTR(optional, Optional,
 SIMPLE_DECL_ATTR(dynamicCallable, DynamicCallable,
   OnNominalType,
   6)
-SIMPLE_DECL_ATTR(noreturn, NoReturn,
-  OnFunc | OnAccessor,
-  7)
+// NOTE: 7 is unused
 SIMPLE_DECL_ATTR(_exported, Exported,
   OnImport |
   UserInaccessible,

include/swift/AST/DiagnosticsSema.def

@@ -1508,9 +1508,6 @@ WARNING(function_type_usable_from_inline_warn,none,
         "'@usableFromInline' %select{function|method|initializer}0 "
         "should be '@usableFromInline' or public",
         (unsigned, bool))
-ERROR(noreturn_not_supported,none,
-      "'@noreturn' has been removed; functions that never return should have a "
-      "return type of 'Never' instead", ())
 
 // Extensions
 ERROR(non_nominal_extension,none,

lib/Sema/TypeCheckAttr.cpp

@@ -123,66 +123,6 @@ class AttributeEarlyChecker : public AttributeVisitor<AttributeEarlyChecker> {
   IGNORED_ATTR(PrivateImport)
 #undef IGNORED_ATTR
 
-  // @noreturn has been replaced with a 'Never' return type.
-  void visitNoReturnAttr(NoReturnAttr *attr) {
-    if (auto FD = dyn_cast<FuncDecl>(D)) {
-      auto &SM = TC.Context.SourceMgr;
-
-      auto diag = TC.diagnose(attr->getLocation(),
-                              diag::noreturn_not_supported);
-      auto range = attr->getRangeWithAt();
-      if (range.isValid())
-        range.End = range.End.getAdvancedLoc(1);
-      diag.fixItRemove(range);
-
-      auto *last = FD->getParameters();
-
-      // If the declaration already has a result type, we're going
-      // to change it to 'Never'.
-      bool hadResultType = false;
-      bool isEndOfLine = false;
-      SourceLoc resultLoc;
-      if (FD->getBodyResultTypeLoc().hasLocation()) {
-        const auto &typeLoc = FD->getBodyResultTypeLoc();
-        hadResultType = true;
-        resultLoc = typeLoc.getSourceRange().Start;
-
-      // If the function 'throws', insert the result type after the
-      // 'throws'.
-      } else {
-        if (FD->getThrowsLoc().isValid()) {
-          resultLoc = FD->getThrowsLoc();
-
-        // Otherwise, insert the result type after the final parameter
-        // list.
-        } else if (last->getRParenLoc().isValid()) {
-          resultLoc = last->getRParenLoc();
-        }
-
-        if (Lexer::getLocForEndOfToken(SM, resultLoc).getAdvancedLoc(1) ==
-            Lexer::getLocForEndOfLine(SM, resultLoc))
-          isEndOfLine = true;
-
-        resultLoc = Lexer::getLocForEndOfToken(SM, resultLoc);
-      }
-
-      if (hadResultType) {
-        diag.fixItReplace(resultLoc, "Never");
-      } else {
-        std::string fix = " -> Never";
-
-        if (!isEndOfLine)
-          fix = fix + " ";
-
-        diag.fixItInsert(resultLoc, fix);
-      }
-
-      auto neverType = TC.Context.getNeverType();
-      if (neverType)
-        FD->getBodyResultTypeLoc() = TypeLoc::withoutLoc(neverType);
-    }
-  }
-
   void visitAlignmentAttr(AlignmentAttr *attr) {
     // Alignment must be a power of two.
     auto value = attr->getValue();
@@ -821,7 +761,6 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
     IGNORED_ATTR(Mutating)
     IGNORED_ATTR(NonMutating)
     IGNORED_ATTR(NonObjC)
-    IGNORED_ATTR(NoReturn)
     IGNORED_ATTR(NSManaged) // checked early.
     IGNORED_ATTR(ObjC)
     IGNORED_ATTR(ObjCBridged)

lib/Sema/TypeCheckDeclOverride.cpp

@@ -1273,7 +1273,6 @@ namespace  {
     UNINTERESTING_ATTR(NonMutating)
     UNINTERESTING_ATTR(NonObjC)
     UNINTERESTING_ATTR(NonOverride)
-    UNINTERESTING_ATTR(NoReturn)
     UNINTERESTING_ATTR(NSApplicationMain)
     UNINTERESTING_ATTR(NSCopying)
     UNINTERESTING_ATTR(NSManaged)

lib/Sema/TypeCheckType.cpp

@@ -2031,7 +2031,7 @@ Type TypeResolver::resolveAttributedType(TypeAttributes &attrs,
   // Pass down the variable function type attributes to the
   // function-type creator.
   static const TypeAttrKind FunctionAttrs[] = {
-    TAK_convention, TAK_noreturn, TAK_pseudogeneric,
+    TAK_convention, TAK_pseudogeneric,
     TAK_callee_owned, TAK_callee_guaranteed, TAK_noescape, TAK_autoclosure,
     TAK_escaping, TAK_yield_once, TAK_yield_many
   };
@@ -2165,17 +2165,6 @@ Type TypeResolver::resolveAttributedType(TypeAttributes &attrs,
         attrs.clearAttribute(TAK_autoclosure);
       }
 
-      // @noreturn has been replaced with a 'Never' return type.
-      if (attrs.has(TAK_noreturn)) {
-        auto loc = attrs.getLoc(TAK_noreturn);
-        auto attrRange = getTypeAttrRangeWithAt(Context, loc);
-        auto resultRange = fnRepr->getResultTypeRepr()->getSourceRange();
-
-        diagnose(loc, diag::noreturn_not_supported)
-            .fixItRemove(attrRange)
-            .fixItReplace(resultRange, "Never");
-      }
-
       // Resolve the function type directly with these attributes.
       FunctionType::ExtInfo extInfo(rep, attrs.has(TAK_noescape),
                                     fnRepr->throws());

test/IDE/complete_decl_attribute.swift

@@ -34,10 +34,9 @@
 @#^KEYWORD2^#
 func method(){}
 
-// KEYWORD2:                  Begin completions, 11 items
+// KEYWORD2:                  Begin completions, 10 items
 // KEYWORD2-NEXT:             Keyword/None:                       available[#Func Attribute#]; name=available{{$}}
 // KEYWORD2-NEXT:             Keyword/None:                       objc[#Func Attribute#]; name=objc{{$}}
-// KEYWORD2-NEXT:             Keyword/None:                       noreturn[#Func Attribute#]; name=noreturn{{$}}
 // KEYWORD2-NEXT:             Keyword/None:                       IBAction[#Func Attribute#]; name=IBAction{{$}}
 // KEYWORD2-NEXT:             Keyword/None:                       NSManaged[#Func Attribute#]; name=NSManaged{{$}}
 // KEYWORD2-NEXT:             Keyword/None:                       inline[#Func Attribute#]; name=inline{{$}}
@@ -91,11 +90,10 @@ struct S{}
 
 @#^KEYWORD_LAST^#
 
-// KEYWORD_LAST:                  Begin completions, 22 items
+// KEYWORD_LAST:                  Begin completions, 21 items
 // KEYWORD_LAST-NEXT:             Keyword/None:                       available[#Declaration Attribute#]; name=available{{$}}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       objc[#Declaration Attribute#]; name=objc{{$}}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       dynamicCallable[#Declaration Attribute#]; name=dynamicCallable
-// KEYWORD_LAST-NEXT:             Keyword/None:                       noreturn[#Declaration Attribute#]; name=noreturn{{$}}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       dynamicMemberLookup[#Declaration Attribute#]; name=dynamicMemberLookup
 // KEYWORD_LAST-NEXT:             Keyword/None:                       NSCopying[#Declaration Attribute#]; name=NSCopying{{$}}
 // KEYWORD_LAST-NEXT:             Keyword/None:                       IBAction[#Declaration Attribute#]; name=IBAction{{$}}