Merge pull request #3901 from CodaFi/dolla-dolla-bills-yall

[Lex] Reject standalone dollars as identifiers

Author: CodaFi

lib/Parse/Lexer.cpp

@@ -805,7 +805,7 @@ void Lexer::lexOperatorIdentifier() {
   return formToken(leftBound ? tok::oper_postfix : tok::oper_prefix, TokStart);
 }
 
-/// lexDollarIdent - Match $[0-9a-zA-Z_$]*
+/// lexDollarIdent - Match $[0-9a-zA-Z_$]+
 void Lexer::lexDollarIdent() {
   const char *tokStart = CurPtr-1;
   assert(*tokStart == '$');
@@ -826,10 +826,15 @@ void Lexer::lexDollarIdent() {
     }
   }
 
-  // It's always an error to see a standalone $, and we reserve
-  // $nonNumeric for persistent bindings in the debugger.
-  if (CurPtr == tokStart + 1 || !isAllDigits) {
-    if (!isAllDigits && !LangOpts.EnableDollarIdentifiers)
+  // It's always an error to see a standalone $
+  if (CurPtr == tokStart + 1) {
+    diagnose(tokStart, diag::expected_dollar_numeric);
+    return formToken(tok::unknown, tokStart);
+  }
+
+  // We reserve $nonNumeric for persistent bindings in the debugger.
+  if (!isAllDigits) {
+    if (!LangOpts.EnableDollarIdentifiers)
       diagnose(tokStart, diag::expected_dollar_numeric);
 
     // Even if we diagnose, we go ahead and form an identifier token,

test/Parse/ConditionalCompilation/compiler_version.swift

@@ -31,7 +31,7 @@
 
 #if !_compiler_version("777.*.7")
   // This shouldn't emit any diagnostics.
-  $#%^*&
+  %#^*&
 #endif
 
 #if _compiler_version("700a.*.10") // expected-error {{version component contains non-numeric characters}}

test/Parse/ConditionalCompilation/language_version.swift

@@ -31,7 +31,7 @@
 
 #if !swift(>=1.0)
   // This shouldn't emit any diagnostics.
-  $#%^*&
+  %#^*&
 #endif
 
 #if swift(">=7.1") // expected-error {{unexpected platform condition argument: expected a unary comparison, such as '>=2.2'}}
@@ -62,7 +62,7 @@ protocol P {
 
   // There should be no error here.
   adsf asdf asdf
-  $#%^*&
+  %#^*&
   func foo(sdfsdfdsf adsf adsf asdf adsf adsf)
 #endif
 }

test/Parse/dollar_identifier.swift

@@ -0,0 +1,29 @@
+// RUN: %target-parse-verify-swift
+
+// SR-1661: Dollar was accidentally allowed as an identifier and identifier head.
+
+func dollarVar() {
+  var $ : Int = 42 // expected-error {{expected numeric value following '$'}} expected-error {{expected pattern}}
+}
+func dollarLet() {
+  let $ = 42 // expected-error {{expected numeric value following '$'}} expected-error {{expected pattern}} 
+}
+func dollarClass() {
+  class $ {} // expected-error {{expected numeric value following '$'}} 
+             // expected-error@-1 {{expression resolves to an unused function}}
+             // expected-error@-2 {{expected identifier in class declaration}}
+             // expected-error@-3 {{braced block of statements is an unused closure}}
+}
+func dollarEnum() {
+  enum $ {} // expected-error {{expected numeric value following '$'}} 
+            // expected-error@-1 {{expected identifier in enum declaration}}
+            // expected-error@-2 {{expression resolves to an unused function}}
+            // expected-error@-3 {{braced block of statements is an unused closure}}
+}
+func dollarStruct() {
+  struct $ {} // expected-error {{expected numeric value following '$'}}
+              // expected-error@-1 {{expected identifier in struct declaration}}
+              // expected-error@-2 {{braced block of statements is an unused closure}}
+              // expected-error@-3 {{expression resolves to an unused function}}
+}
+