Scott Murphy Heiberg created GROOVY-12695:
---------------------------------------------
Summary: Primitive type keyword used as a variable name gets
inconsistent and misleading diagnostics
Key: GROOVY-12695
URL: https://issues.apache.org/jira/browse/GROOVY-12695
Project: Groovy
Issue Type: Bug
Components: parser
Affects Versions: 6.0.0
Reporter: Scott Murphy Heiberg
*Environment:* macOS 26.5, BellSoft Liberica JDK 21.0.12; reproduced with the
{{groovy}} command of each distribution
h3. Problem
Declaring a local variable named after a primitive type keyword is rejected (as
it should be), but the message depends on which declaration keyword was used,
and neither message says what is wrong.
{code}
var long = 1
val long = 1
def long = 1
final long = 1
{code}
h3. Actual
{{var}} and {{val}} report a resolve-phase message that talks about assigning
to a class, with the caret on the keyword:
{noformat}
var_long.groovy: 1: you tried to assign a value to the class 'long'
@ line 1, column 5.
var long = 1
^
{noformat}
{noformat}
val_long.groovy: 1: you tried to assign a value to the class 'long'
@ line 1, column 5.
val long = 1
^
{noformat}
{{def}} and {{final}} report a generic syntax error with the caret on the
{{=}}, one token past the mistake:
{noformat}
def_long.groovy: 1: Unexpected input: 'def long =' @ line 1, column 10.
def long = 1
^
{noformat}
{noformat}
final_long.groovy: 1: Unexpected input: 'final long =' @ line 1, column 12.
final long = 1
^
{noformat}
Other primitive names and {{void}} behave the same way ({{var int = 1}} reports
{{you tried to assign a value to the class 'int'}}, {{def int = 1}} reports
{{Unexpected input: 'def int ='}}). Inside a method body {{def long = 1}}
reports {{Unexpected input: '='}} on the {{=}}. The same two shapes also appear
for a typed declaration ({{String long = "x"}} and {{int long = 1}} report the
class message, a field {{class C { int long = 1 }}} reports {{Unexpected input:
'int long'}}) and for a bare {{long = 1}}.
h3. Cause
{{var}} and {{val}} are soft keywords, so when {{var long = 1}} fails to parse
as a declaration the parser accepts it as the command expression {{var(long =
1)}}; {{AstBuilder}} builds an assignment whose left-hand side is the built-in
type name, and {{ResolveVisitor}} later reports it as an assignment to a class.
({{var long}} without an initializer actually runs, as a call to a method named
{{var}}.) {{def}} and {{final}} are reserved, so the parser commits to a
declaration, consumes {{long}} as the declared type and fails on the {{=}} with
the generic {{Unexpected input}} sentence.
h3. Expected
One diagnostic for every form, naming the keyword, with the caret on the
keyword:
{noformat}
'long' is a keyword and cannot be used as a variable name @ line 1, column 5.
var long = 1
^
{noformat}
This is in line with the other developer-facing parser sentences added in
GROOVY-12353 and GROOVY-12401.
A pull request with regression tests follows.
h3. Versions
Reproduced on 6.0.0, 6.0.1-SNAPSHOT (GROOVY_6_0_X at 7c0dcf17dd) and master
(d86ea7eb85).
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