Merge pull request #24059 from sl/sl/sr-10293

Allow var / let as parameter names but provide a warning and fixit to add backticks.

include/swift/AST/DiagnosticsParse.def

@@ -852,10 +852,9 @@ ERROR(parameter_specifier_as_attr_disallowed,none,
       "'%0' before a parameter name is not allowed, place it before the parameter type instead",
       (StringRef))
 ERROR(parameter_specifier_repeated,none,
-      "parameter must not have multiple '__owned', 'inout', '__shared',"
-      " 'var', or 'let' specifiers", ())
-ERROR(parameter_let_var_as_attr,none,
-      "'%0' as a parameter attribute is not allowed",
+      "parameter must not have multiple '__owned', 'inout', or '__shared' specifiers", ())
+WARNING(parameter_let_var_as_attr,none,
+      "'%0' in this position is interpreted as an argument label",
       (StringRef))
 
 

include/swift/Parse/Parser.h

@@ -609,6 +609,8 @@ public:
 
   void skipUntilDeclRBrace(tok T1, tok T2);
   
+  void skipListUntilDeclRBrace(SourceLoc startLoc, tok T1, tok T2);
+  
   /// Skip a single token, but match parentheses, braces, and square brackets.
   ///
   /// Note: this does \em not match angle brackets ("<" and ">")! These are

include/swift/Parse/Token.h

@@ -173,8 +173,8 @@ public:
       return true;
     }
 
-    // 'let', 'var', and 'inout' cannot be argument labels.
-    if (isAny(tok::kw_let, tok::kw_var, tok::kw_inout))
+    // inout cannot be used as an argument label.
+    if (is(tok::kw_inout))
       return false;
 
     // All other keywords can be argument labels.