Merge pull request #37720 from hamishknight/all-the-patter

Author: hamishknight

include/swift/AST/DiagnosticsRefactoring.def

@@ -70,5 +70,7 @@ ERROR(callback_multiple_case_items, none, "cannot refactor switch using a case w
 
 ERROR(callback_where_case_item, none, "cannot refactor switch using a case with where clause", ())
 
+ERROR(unknown_callback_case_item, none, "cannot refactor complex case conditions", ())
+
 #define UNDEFINE_DIAGNOSTIC_MACROS
 #include "DefineDiagnosticMacros.h"

include/swift/AST/Pattern.h

@@ -202,6 +202,9 @@ class alignas(8) Pattern {
   /// Does this binding declare something that requires storage?
   bool hasStorage() const;
 
+  /// Does this pattern have any mutable 'var' bindings?
+  bool hasAnyMutableBindings() const;
+
   static bool classof(const Pattern *P) { return true; }
 
   //*** Allocation Routines ************************************************/

include/swift/IDE/SourceEntityWalker.h

@@ -73,6 +73,9 @@ class SourceEntityWalker {
   /// Walks the provided Expr.
   /// \returns true if traversal was aborted, false otherwise.
   bool walk(Expr *E);
+  /// Walks the provided Pattern.
+  /// \returns true if traversal was aborted, false otherwise.
+  bool walk(Pattern *P);
   /// Walks the provided ASTNode.
   /// \returns true if traversal was aborted, false otherwise.
   bool walk(ASTNode N);
@@ -101,6 +104,14 @@ class SourceEntityWalker {
   /// returns false, the remaining traversal is terminated and returns failure.
   virtual bool walkToExprPost(Expr *E) { return true; }
 
+  /// This method is called when first visiting a pattern, before walking
+  /// into its children. If it returns false, the subtree is skipped.
+  virtual bool walkToPatternPre(Pattern *P) { return true; }
+
+  /// This method is called after visiting the children of a pattern. If it
+  /// returns false, the remaining traversal is terminated and returns failure.
+  virtual bool walkToPatternPost(Pattern *P) { return true; }
+
   /// This method is called when a ValueDecl is referenced in source. If it
   /// returns false, the remaining traversal is terminated and returns failure.
   ///

lib/AST/Pattern.cpp

@@ -291,6 +291,15 @@ bool Pattern::hasStorage() const {
   return HasStorage;
 }
 
+bool Pattern::hasAnyMutableBindings() const {
+  auto HasMutable = false;
+  forEachVariable([&](VarDecl *VD) {
+    if (!VD->isLet())
+      HasMutable = true;
+  });
+  return HasMutable;
+}
+
 /// Return true if this is a non-resolved ExprPattern which is syntactically
 /// irrefutable.
 static bool isIrrefutableExprPattern(const ExprPattern *EP) {