SI-9015 Reject 0x and minor parser cleanup

Only print error results.  Show deprecated forms.

Test for rejected literals and clean up parser

There was no negative test for what constitutes a legal literal.

The ultimate goal is for the test to report all errors in
one compilation.

This commit follows up the removal of "1." syntax to simplify
number parsing.  It removes previous paulp code to contain the
erstwhile complexity.

Leading zero is not immediately put to the buffer.  Instead,
the empty buffer is handled on evaluation.  In particular, an
empty buffer due to `0x` is a syntax error.

The message for obsolete octal syntax is nuanced and deferred
until evaluation by the parser, which is slightly simpler to
reason about.

Improve comment on usage of base

The slice-and-dicey usage of base deserves a better
comment. The difference is that `intVal` sees an empty
char buffer for input `"0"`.

1 files changed, 40 insertions, 0 deletions

diff --git a/test/files/neg/literals.check b/test/files/neg/literals.check
new file mode 100644
index 0000000000..148a9346c5
--- /dev/null
+++ b/test/files/neg/literals.check
@@ -0,0 +1,40 @@
+literals.scala:6: error: missing integer number
+  def missingHex: Int    = { 0x }        // line 4: was: not reported, taken as zero
+                             ^
+literals.scala:8: error: Decimal integer literals may not have a leading zero. (Octal syntax is obsolete.)
+  def leadingZeros: Int  = { 01 }        // line 6: no leading zero
+                             ^
+literals.scala:10: error: Decimal integer literals may not have a leading zero. (Octal syntax is obsolete.)
+  def tooManyZeros: Int  = { 00 }        // line 8: no leading zero
+                             ^
+literals.scala:12: error: Decimal integer literals may not have a leading zero. (Octal syntax is obsolete.)
+  def zeroOfNine: Int    = { 09 }        // line 10: no leading zero
+                             ^
+literals.scala:16: error: Decimal integer literals may not have a leading zero. (Octal syntax is obsolete.)
+  def zeroOfNineDot: Int = { 09. }       // line 14: malformed integer, ident expected
+                             ^
+literals.scala:23: error: missing integer number
+  def missingHex: Int    = 0x            // line 22: was: not reported, taken as zero
+                           ^
+literals.scala:27: error: Decimal integer literals may not have a leading zero. (Octal syntax is obsolete.)
+  def tooManyZeros: Int  = 00            // line 26: no leading zero
+                           ^
+literals.scala:14: error: identifier expected but '}' found.
+  def orphanDot: Int     = { 9. }        // line 12: ident expected
+                                ^
+literals.scala:16: error: identifier expected but '}' found.
+  def zeroOfNineDot: Int = { 09. }       // line 14: malformed integer, ident expected
+                                 ^
+literals.scala:18: error: ';' expected but double literal found.
+  def noHexFloat: Double = { 0x1.2 }     // line 16: ';' expected but double literal found.
+                                ^
+literals.scala:25: error: ';' expected but 'def' found.
+  def leadingZeros: Int  = 01            // line 24: no leading zero
+  ^
+literals.scala:29: error: ';' expected but 'def' found.
+  def zeroOfNine: Int    = 09            // line 28: no leading zero
+  ^
+literals.scala:33: error: identifier expected but 'def' found.
+  def zeroOfNineDot: Int = 09.           // line 32: malformed integer, ident expected
+  ^
+13 errors found