Merge pull request swiftlang#38391 from wongzigii/SR-14883

[SR-14883] Improve diagnostic error message for empty cases

Author: varungandhi-apple

include/swift/AST/DiagnosticsParse.def

@@ -1139,7 +1139,7 @@ ERROR(default_with_where,none,
       "'default' cannot be used with a 'where' guard expression",
       ())
 ERROR(case_stmt_without_body,none,
-      "%select{'case'|'default'}0 label in a 'switch' should have at least one "
+      "%select{'case'|'default'}0 label in a 'switch' must have at least one "
       "executable statement", (bool))
 
 // 'try' on statements

test/Constraints/result_builder_diags.swift

@@ -652,7 +652,7 @@ struct MyView {
 
   @TupleBuilder var invalidSwitchMultiple: some P {
     switch Optional.some(1) {
-    case .none: // expected-error {{'case' label in a 'switch' should have at least one executable statement}}
+    case .none: // expected-error {{'case' label in a 'switch' must have at least one executable statement}}
     case . // expected-error {{expected ':' after 'case'}}
     } // expected-error {{expected identifier after '.' expression}}
   }

test/Parse/switch.swift

@@ -72,27 +72,27 @@ default:
 
 // Multiple cases per case block
 switch x { // expected-error {{switch must be exhaustive}} expected-note{{do you want to add a default clause?}}
-case 0: // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{8-8= break}}
+case 0: // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{8-8= break}}
 case 1:
   x = 0
 }
 
 switch x {
-case 0: // expected-error{{'case' label in a 'switch' should have at least one executable statement}} {{8-8= break}}
+case 0: // expected-error{{'case' label in a 'switch' must have at least one executable statement}} {{8-8= break}}
 default:
   x = 0
 }
 
 switch x { // expected-error {{switch must be exhaustive}} expected-note{{do you want to add a default clause?}}
 case 0:
   x = 0
-case 1: // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{8-8= break}}
+case 1: // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{8-8= break}}
 }
 
 switch x {
 case 0:
   x = 0
-default: // expected-error {{'default' label in a 'switch' should have at least one executable statement}} {{9-9= break}}
+default: // expected-error {{'default' label in a 'switch' must have at least one executable statement}} {{9-9= break}}
 }
 
 switch x { // expected-error {{switch must be exhaustive}} expected-note{{do you want to add a default clause?}}
@@ -131,13 +131,13 @@ switch x { // expected-error{{'switch' statement body must have at least one 'ca
 }
 
 switch x {
-default: // expected-error{{'default' label in a 'switch' should have at least one executable statement}} {{9-9= break}}
+default: // expected-error{{'default' label in a 'switch' must have at least one executable statement}} {{9-9= break}}
 case 0: // expected-error{{additional 'case' blocks cannot appear after the 'default' block of a 'switch'}}
   x = 0
 }
 
 switch x {
-default: // expected-error{{'default' label in a 'switch' should have at least one executable statement}} {{9-9= break}}
+default: // expected-error{{'default' label in a 'switch' must have at least one executable statement}} {{9-9= break}}
 default: // expected-error{{additional 'case' blocks cannot appear after the 'default' block of a 'switch'}}
   x = 0
 }
@@ -148,19 +148,19 @@ default where x == 0: // expected-error{{'default' cannot be used with a 'where'
 }
 
 switch x { // expected-error {{switch must be exhaustive}} expected-note{{do you want to add a default clause?}}
-case 0: // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{8-8= break}}
+case 0: // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{8-8= break}}
 }
 
 switch x { // expected-error {{switch must be exhaustive}} expected-note{{do you want to add a default clause?}}
-case 0: // expected-error{{'case' label in a 'switch' should have at least one executable statement}} {{8-8= break}}
+case 0: // expected-error{{'case' label in a 'switch' must have at least one executable statement}} {{8-8= break}}
 case 1:
   x = 0
 }
 
 switch x { // expected-error {{switch must be exhaustive}} expected-note{{do you want to add a default clause?}}
 case 0:
   x = 0
-case 1: // expected-error{{'case' label in a 'switch' should have at least one executable statement}} {{8-8= break}}
+case 1: // expected-error{{'case' label in a 'switch' must have at least one executable statement}} {{8-8= break}}
 }
 
 
@@ -206,15 +206,15 @@ case (_, 2), (var a, _): // expected-error {{'a' must be bound in every pattern}
 case (var a, 2), (1, var b): // expected-error {{'a' must be bound in every pattern}} expected-error {{'b' must be bound in every pattern}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
   ()
 
-case (var a, 2): // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{17-17= break}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
+case (var a, 2): // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{17-17= break}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
 case (1, _):
   ()
 
-case (_, 2): // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{13-13= break}}
+case (_, 2): // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{13-13= break}}
 case (1, var a): // expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
   ()
 
-case (var a, 2): // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{17-17= break}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
+case (var a, 2): // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{17-17= break}} expected-warning {{variable 'a' was never used; consider replacing with '_' or removing it}}
 case (1, var b): // expected-warning {{variable 'b' was never used; consider replacing with '_' or removing it}}
   ()
 
@@ -238,7 +238,7 @@ case (var a, var b), (var b, var a): // expected-warning {{variable 'a' was neve
   // expected-warning@-2 {{case is already handled by previous patterns; consider removing it}}
   ()
 
-case (_, 2): // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{13-13= break}}
+case (_, 2): // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{13-13= break}}
 case (1, _):
   ()
 }
@@ -353,27 +353,27 @@ func f1(x: String, y: Whichever) {
 
 
 switch Whatever.Thing {
-case .Thing: // expected-error{{'case' label in a 'switch' should have at least one executable statement}} {{13-13= break}}
+case .Thing: // expected-error{{'case' label in a 'switch' must have at least one executable statement}} {{13-13= break}}
 @unknown case _:
   x = 0
 }
 
 switch Whatever.Thing {
-case .Thing: // expected-error{{'case' label in a 'switch' should have at least one executable statement}} {{13-13= break}}
+case .Thing: // expected-error{{'case' label in a 'switch' must have at least one executable statement}} {{13-13= break}}
 @unknown default:
   x = 0
 }
 
 switch Whatever.Thing {
 case .Thing:
   x = 0
-@unknown case _: // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{17-17= break}}
+@unknown case _: // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{17-17= break}}
 }
 
 switch Whatever.Thing {
 case .Thing:
   x = 0
-@unknown default: // expected-error {{'default' label in a 'switch' should have at least one executable statement}} {{18-18= break}}
+@unknown default: // expected-error {{'default' label in a 'switch' must have at least one executable statement}} {{18-18= break}}
 }
 
 

test/stmt/statements.swift

@@ -412,7 +412,7 @@ func matching_pattern_recursion() {
 // <rdar://problem/18776073> Swift's break operator in switch should be indicated in errors
 func r18776073(_ a : Int?) {
   switch a {
-    case nil:   // expected-error {{'case' label in a 'switch' should have at least one executable statement}} {{14-14= break}}
+    case nil:   // expected-error {{'case' label in a 'switch' must have at least one executable statement}} {{14-14= break}}
     case _?: break
   }
 }