[[FIX]] Improve numeric literal warnings/errors

Previously, JSHint issued the warning W045 in response to invalid
numeric literals and numeric literals which could not be represented
with the JavaScript "number" type. (The existing code comment which
claims otherwise is erroneous.) While the warning's message was generic
enough to describe both cases ("Bad number"), the dual usage undermined
JSHint's distinction between "errors" and "warnings."

Create a new error to describe the invalid syntax and emit it as
appropriate. Reword the existing warning to more precisely describe the
likely programming error it reflects.

src/lex.js

@@ -966,11 +966,19 @@ Lexer.prototype = {
       }
     }
 
+    // TODO: Extend this check to other numeric literals
+    this.triggerAsync("warning", {
+      code: "W045",
+      line: this.line,
+      character: this.char + value.length,
+      data: [ value ]
+    }, checks, function() { return !isFinite(value); });
+
     return {
       type: Token.NumericLiteral,
       value: value,
       base: base,
-      isMalformed: !isFinite(value)
+      isMalformed: false
     };
   },
 
@@ -2143,10 +2151,8 @@ Lexer.prototype = {
 
       case Token.NumericLiteral:
         if (token.isMalformed) {
-          // This condition unequivocally describes a syntax error.
-          // TODO: Re-factor as an "error" (not a "warning").
-          this.trigger("warning", {
-            code: "W045",
+          this.trigger("error", {
+            code: "E067",
             line: this.line,
             character: this.char,
             data: [ token.value ]

src/messages.js

@@ -82,7 +82,8 @@ var errors = {
   E064: "Super call may only be used within class method bodies.",
   E065: "Functions defined outside of strict mode with non-simple parameter lists may not " +
     "enable strict mode.",
-  E066: "Asynchronous iteration is only available with for-of loops."
+  E066: "Asynchronous iteration is only available with for-of loops.",
+  E067: "Malformed numeric literal: '{a}'."
 };
 
 var warnings = {
@@ -131,7 +132,8 @@ var warnings = {
   W042: "Avoid EOL escaping.",
   W043: "Bad escaping of EOL. Use option multistr if needed.",
   W044: "Bad or unnecessary escaping.", /* TODO(caitp): remove W044 */
-  W045: "Bad number '{a}'.",
+  W045: "Value described by numeric literal cannot be accurately " +
+    "represented with a number value: '{a}'.",
   W046: "Don't use extra leading zeros '{a}'.",
   W047: "A trailing decimal point can be confused with a dot: '{a}'.",
   W048: "Unexpected control character in regular expression.",

tests/test262/expectations.txt

@@ -150,15 +150,7 @@ test/language/rest-parameters/object-pattern.js(strict mode)
 test/language/arguments-object/10.6-13-c-1-s.js(strict mode)
 test/language/arguments-object/10.6-1gs.js(strict mode)
 test/language/arguments-object/10.6-2gs.js(strict mode)
-test/language/literals/numeric/S7.8.3_A6.1_T1.js(default)
-test/language/literals/numeric/S7.8.3_A6.1_T1.js(strict mode)
-test/language/literals/numeric/S7.8.3_A6.1_T2.js(default)
-test/language/literals/numeric/S7.8.3_A6.1_T2.js(strict mode)
-test/language/literals/numeric/binary-invalid-truncated.js(default)
-test/language/literals/numeric/binary-invalid-truncated.js(strict mode)
 test/language/literals/numeric/non-octal-decimal-integer-strict.js(strict mode)
-test/language/literals/numeric/octal-invalid-truncated.js(default)
-test/language/literals/numeric/octal-invalid-truncated.js(strict mode)
 test/language/block-scope/syntax/function-declarations/in-statement-position-if-expression-statement-else-statement.js(strict mode)
 test/language/block-scope/syntax/function-declarations/in-statement-position-if-expression-statement.js(strict mode)
 test/language/destructuring/binding/syntax/array-elements-with-initializer.js(default)

tests/unit/parser.js

@@ -537,7 +537,7 @@ exports.numbers = function (test) {
   ];
 
   TestRun(test)
-    .addError(2, 15, "Bad number '10e308'.")
+    .addError(2, 15, "Value described by numeric literal cannot be accurately represented with a number value: '10e308'.")
     .addError(5, 11, "A leading decimal point can be confused with a dot: '.3'.")
     .addError(6, 9, "Unexpected '0'.")
     .addError(7, 1, "Expected an identifier and instead saw 'var'.")
@@ -547,7 +547,7 @@ exports.numbers = function (test) {
     .addError(9, 9, "A dot following a number can be confused with a decimal point.")
     .addError(11, 9, "'Octal integer literal' is only available in ES6 (use 'esversion: 6').")
     .addError(12, 9, "'Binary integer literal' is only available in ES6 (use 'esversion: 6').")
-    .addError(13, 11, "Bad number '0x'.")
+    .addError(13, 11, "Malformed numeric literal: '0x'.")
     .addError(15, 9, "Unexpected '1'.")
     .addError(16, 11, "Expected an identifier and instead saw ';'.")
     .addError(16, 1, "Expected an identifier and instead saw 'var'.")

tests/unit/unstable/bigint.js

@@ -75,19 +75,19 @@ exports.invalid = function (test) {
     .test("void 1e3n;", {esversion: 6, unstable: {bigint: true}});
 
   TestRun(test, "invalid hex digit")
-    .addError(1, 8, "Bad number '0x'.")
+    .addError(1, 8, "Malformed numeric literal: '0x'.")
     .addError(1, 8, "Missing semicolon.")
     .addError(1, 8, "Expected an assignment or function call and instead saw an expression.")
     .test("void 0xgn;", {esversion: 6, unstable: {bigint: true}});
 
   TestRun(test, "invalid binary digit")
-    .addError(1, 8, "Bad number '0b'.")
+    .addError(1, 8, "Malformed numeric literal: '0b'.")
     .addError(1, 8, "Missing semicolon.")
     .addError(1, 8, "Expected an assignment or function call and instead saw an expression.")
     .test("void 0b2n;", {esversion: 6, unstable: {bigint: true}});
 
   TestRun(test, "invalid octal digit")
-    .addError(1, 8, "Bad number '0o'.")
+    .addError(1, 8, "Malformed numeric literal: '0o'.")
     .addError(1, 8, "Missing semicolon.")
     .addError(1, 8, "Expected an assignment or function call and instead saw an expression.")
     .test("void 0o8n;", {esversion: 6, unstable: {bigint: true}});