Merge pull request #8738 from wolframw/issue_19246

Fix Issue 19246 - Binary literal `0b_` allowed
dlang · Nov 6, 2018 · d6e4bbb · d6e4bbb
2 parents 3074a3d + 1caed61
commit d6e4bbb
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Showing 3 changed files with 32 additions and 4 deletions.
diff --git a/changelog/deprecated_binary_literals.dd b/changelog/deprecated_binary_literals.dd
@@ -0,0 +1,9 @@
+Deprecate invalid binary literals
+
+Prior to this release, binary literals without any digits after the prefix `0b`
+were considered valid. This has now been deprecated.
+---
+auto foo = 0b;   // deprecated
+auto bar = 0b_;  // deprecated
+auto baz = 0b0;  // conforming equivalent
+---
diff --git a/src/dmd/lexer.d b/src/dmd/lexer.d
@@ -1803,7 +1803,7 @@ class Lexer : ErrorHandler
         int d;
         bool err = false;
         bool overflow = false;
-        bool anyBinaryDigitsUS = false;
+        bool anyBinaryDigitsNoSingleUS = false;
         bool anyHexDigitsNoSingleUS = false;
         dchar c = *p;
         if (c == '0')
@@ -1914,15 +1914,14 @@ class Lexer : ErrorHandler
                 p = start;
                 return inreal(t);
             case '_':
-                anyBinaryDigitsUS = true;
                 ++p;
                 continue;
             default:
                 goto Ldone;
             }
             // got a digit here, set any necessary flags, check for errors
             anyHexDigitsNoSingleUS = true;
-            anyBinaryDigitsUS = true;
+            anyBinaryDigitsNoSingleUS = true;
             if (!err && d >= base)
             {
                 error("%s digit expected, not `%c`", base == 2 ? "binary".ptr :
@@ -1950,7 +1949,7 @@ class Lexer : ErrorHandler
         // Deprecated in 2018-06.
         // Change to error in 2019-06.
         // @@@DEPRECATED_2019-06@@@
-        if ((base == 2 && !anyBinaryDigitsUS) ||
+        if ((base == 2 && !anyBinaryDigitsNoSingleUS) ||
             (base == 16 && !anyHexDigitsNoSingleUS))
             deprecation("`%.*s` isn't a valid integer literal, use `%.*s0` instead", cast(int)(p - start), start, 2, start);
         enum FLAGS : int

diff --git a/test/fail_compilation/fix19246.d b/test/fail_compilation/fix19246.d
@@ -0,0 +1,20 @@
+/* REQUIRED_ARGS: -de
+ * PERMUTE_ARGS:
+ * TEST_OUTPUT:
+---
+fail_compilation/fix19246.d(16): Deprecation: `0b_` isn't a valid integer literal, use `0b0` instead
+fail_compilation/fix19246.d(17): Deprecation: `0B_` isn't a valid integer literal, use `0B0` instead
+fail_compilation/fix19246.d(18): Deprecation: `0b` isn't a valid integer literal, use `0b0` instead
+fail_compilation/fix19246.d(19): Deprecation: `0B` isn't a valid integer literal, use `0B0` instead
+---
+ */
+
+// https://issues.dlang.org/show_bug.cgi?id=19246
+
+void foo()
+{
+    auto a = 0b_;
+    auto b = 0B_;
+    auto c = 0b;
+    auto d = 0B;
+}