Spruce Up Static/Class Diagnostics

Mention the let/var character of the property in addition to its static
spelling kind. Then drop the reference to "specifier". As icing on top,
offer to insert an initializer after any binding patterns.

rdar://19827674

Author: CodaFi

include/swift/AST/DiagnosticsSema.def

@@ -1553,10 +1553,13 @@ ERROR(observingprop_requires_initializer,none,
       "non-member observing properties require an initializer", ())
 ERROR(global_requires_initializer,none,
       "global '%select{var|let}0' declaration requires an initializer expression"
-      "%select{ or getter/setter specifier|}0", (bool))
+      "%select{ or an explicitly stated getter|}0", (bool))
 ERROR(static_requires_initializer,none,
-      "%select{ERROR|'static var'|'class var'|}0 declaration requires an initializer "
-      "expression or getter/setter specifier", (StaticSpellingKind))
+      "'%select{ERROR|static|class|}0 %select{var|let}1' declaration requires "
+      "an initializer expression or an explicitly stated getter",
+      (StaticSpellingKind, bool))
+NOTE(static_requires_initializer_add_init,none,
+      "add an initializer to silence this error", ())
 ERROR(pattern_type_access,none,
       "%select{%select{variable|constant}0|property}1 "
       "%select{must be declared %select{"

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -1622,7 +1622,8 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
           Ctx.evaluator, PatternBindingEntryRequest{PBD, i}, nullptr);
       assert(entry && "No pattern binding entry?");
 
-      PBD->getPattern(i)->forEachVariable([&](VarDecl *var) {
+      const auto *Pat = PBD->getPattern(i);
+      Pat->forEachVariable([&](VarDecl *var) {
         this->visitBoundVariable(var);
 
         if (PBD->isInitialized(i)) {
@@ -1680,7 +1681,10 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
           }
 
           var->diagnose(diag::static_requires_initializer,
-                        var->getCorrectStaticSpelling());
+                        var->getCorrectStaticSpelling(),
+                        var->isLet());
+          var->diagnose(diag::static_requires_initializer_add_init)
+            .fixItInsert(Pat->getEndLoc(), " = <#initializer#>");
           markVarAndPBDInvalid();
           return;
         }
@@ -1697,6 +1701,8 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
           }
 
           var->diagnose(diag::global_requires_initializer, var->isLet());
+          var->diagnose(diag::static_requires_initializer_add_init)
+            .fixItInsert(Pat->getEndLoc(), " = <#initializer#>");
           markVarAndPBDInvalid();
           return;
         }

test/decl/var/static_var.swift

@@ -2,21 +2,27 @@
 
 // See also rdar://15626843.
 static var gvu1: Int // expected-error {{static properties may only be declared on a type}}{{1-8=}}
-    // expected-error@-1 {{global 'var' declaration requires an initializer expression or getter/setter specifier}}
+    // expected-error@-1 {{global 'var' declaration requires an initializer expression or an explicitly stated getter}}
+    // expected-note@-2 {{add an initializer to silence this error}} {{18-18= = <#initializer#>}}
 class var gvu2: Int // expected-error {{class properties may only be declared on a type}}{{1-7=}}
-    // expected-error@-1 {{global 'var' declaration requires an initializer expression or getter/setter specifier}}
+    // expected-error@-1 {{global 'var' declaration requires an initializer expression or an explicitly stated getter}}
+    // expected-note@-2 {{add an initializer to silence this error}} {{17-17= = <#initializer#>}}
 override static var gvu3: Int // expected-error {{static properties may only be declared on a type}}{{10-17=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{1-10=}}
-    // expected-error@-2 {{global 'var' declaration requires an initializer expression or getter/setter specifier}}
+    // expected-error@-2 {{global 'var' declaration requires an initializer expression or an explicitly stated getter}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{27-27= = <#initializer#>}}
 override class var gvu4: Int // expected-error {{class properties may only be declared on a type}}{{10-16=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{1-10=}}
-    // expected-error@-2 {{global 'var' declaration requires an initializer expression or getter/setter specifier}}
+    // expected-error@-2 {{global 'var' declaration requires an initializer expression or an explicitly stated getter}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{26-26= = <#initializer#>}}
 static override var gvu5: Int // expected-error {{static properties may only be declared on a type}}{{1-8=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{8-17=}}
-    // expected-error@-2 {{global 'var' declaration requires an initializer expression or getter/setter specifier}}
+    // expected-error@-2 {{global 'var' declaration requires an initializer expression or an explicitly stated getter}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{27-27= = <#initializer#>}}
 class override var gvu6: Int // expected-error {{class properties may only be declared on a type}}{{1-7=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{7-16=}}
-    // expected-error@-2 {{global 'var' declaration requires an initializer expression or getter/setter specifier}}
+    // expected-error@-2 {{global 'var' declaration requires an initializer expression or an explicitly stated getter}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{26-26= = <#initializer#>}}
 
 static var gvu7: Int { // expected-error {{static properties may only be declared on a type}}{{1-8=}}
   return 42
@@ -28,20 +34,26 @@ class var gvu8: Int { // expected-error {{class properties may only be declared
 
 static let glu1: Int // expected-error {{static properties may only be declared on a type}}{{1-8=}}
     // expected-error@-1 {{global 'let' declaration requires an initializer expression}}
+    // expected-note@-2 {{add an initializer to silence this error}} {{18-18= = <#initializer#>}}
 class let glu2: Int // expected-error {{class properties may only be declared on a type}}{{1-7=}}
     // expected-error@-1 {{global 'let' declaration requires an initializer expression}}
+    // expected-note@-2 {{add an initializer to silence this error}} {{17-17= = <#initializer#>}}
 override static let glu3: Int // expected-error {{static properties may only be declared on a type}}{{10-17=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{1-10=}}
     // expected-error@-2 {{global 'let' declaration requires an initializer expression}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{27-27= = <#initializer#>}}
 override class let glu4: Int // expected-error {{class properties may only be declared on a type}}{{10-16=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{1-10=}}
     // expected-error@-2 {{global 'let' declaration requires an initializer expression}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{26-26= = <#initializer#>}}
 static override let glu5: Int // expected-error {{static properties may only be declared on a type}}{{1-8=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{8-17=}}
     // expected-error@-2 {{global 'let' declaration requires an initializer expression}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{27-27= = <#initializer#>}}
 class override let glu6: Int // expected-error {{class properties may only be declared on a type}}{{1-7=}}
     // expected-error@-1 {{'override' can only be specified on class members}}{{7-16=}}
     // expected-error@-2 {{global 'let' declaration requires an initializer expression}}
+    // expected-note@-3 {{add an initializer to silence this error}} {{26-26= = <#initializer#>}}
 
 
 static var gvi1: Int = 0 // expected-error {{static properties may only be declared on a type}}{{1-8=}}
@@ -187,7 +199,8 @@ extension P {
 
 struct S1 {
   // rdar://15626843
-  static var x: Int  // expected-error {{'static var' declaration requires an initializer expression or getter/setter specifier}}
+  static var x: Int  // expected-error {{'static var' declaration requires an initializer expression or an explicitly stated getter}}
+  // expected-note@-1 {{add an initializer to silence this error}} {{17-17= = <#initializer#>}}
   var y = 1
 
   static var z = 5
@@ -205,7 +218,20 @@ enum E1 {
 }
 
 class C1 {
-  class var x: Int // expected-error {{class stored properties not supported}} expected-error {{'class var' declaration requires an initializer expression or getter/setter specifier}}
+  class var x: Int // expected-error {{class stored properties not supported}} expected-error {{'class var' declaration requires an initializer expression or an explicitly stated getter}}
+  // expected-note@-1 {{add an initializer to silence this error}} {{16-16= = <#initializer#>}}
+  class let x: Int // expected-error {{class stored properties not supported}} expected-error {{'class let' declaration requires an initializer expression or an explicitly stated getter}}
+  // expected-note@-1 {{add an initializer to silence this error}} {{16-16= = <#initializer#>}}
+  static var x: Int // expected-error {{'static var' declaration requires an initializer expression or an explicitly stated getter}}
+  // expected-note@-1 {{add an initializer to silence this error}} {{17-17= = <#initializer#>}}
+  static let x: Int // expected-error {{'static let' declaration requires an initializer expression or an explicitly stated getter}}
+  // expected-note@-1 {{add an initializer to silence this error}} {{17-17= = <#initializer#>}}
+
+  // FIXME: We immediately invalidate the pattern binding after the first error
+  // is emitted, but we could definitely emit a second round of fixits for the
+  // other pattern here.
+  static var (x, y): (Int, Int), (z, w): (Int, Int)  // expected-error {{'static var' declaration requires an initializer expression or an explicitly stated getter}}
+  // expected-note@-1 {{add an initializer to silence this error}} {{31-31= = <#initializer#>}}
 }
 
 class C2 {