Assertion failure with annotations

[Praetonus]

Minimal example:

actor Main
  new create(env: Env) =>
    if \likely\ U32(1) == 1 then
      None
    end

Using annotations on an expression results in an assertion failure:

src/libponyc/ast/ast.c:737: setannotation: Assertion `!hasparent(annotation) && (annotation->annotation_type == NULL)` failed.

Backtrace:

#2  0x0000000000502349 in ponyint_assert_fail (expr=0x50a12c "!hasparent(annotation) && (annotation->annotation_type == NULL)", file=0x509f07 "src/libponyc/ast/ast.c", 
    line=743, func=0x50a11e "setannotation") at src/libponyrt/platform/ponyassert.c:60
#3  0x0000000000432ddb in setannotation (ast=0x7ffff0559300, annotation=0x7ffff0490d80, allow_free=true) at src/libponyc/ast/ast.c:742
#4  0x0000000000433022 in ast_setannotation (ast=0x7ffff0559300, annotation=0x7ffff0490d80) at src/libponyc/ast/ast.c:769
#5  0x0000000000431cb0 in duplicate (parent=0x7ffff0524a80, ast=0x7ffff2f47c40) at src/libponyc/ast/ast.c:361
#6  0x0000000000431d1c in duplicate (parent=0x7ffff0524a80, ast=0x7ffff2f495c0) at src/libponyc/ast/ast.c:368
#7  0x0000000000431d1c in duplicate (parent=0x7ffff0524a80, ast=0x7ffff2f49bc0) at src/libponyc/ast/ast.c:368
#8  0x0000000000431c7c in duplicate (parent=0x7ffff0492cc0, ast=0x7ffff2f48a40) at src/libponyc/ast/ast.c:359
#9  0x0000000000431d1c in duplicate (parent=0x7ffff0492cc0, ast=0x7ffff2f49e80) at src/libponyc/ast/ast.c:368
#10 0x0000000000431d1c in duplicate (parent=0x7ffff0492cc0, ast=0x7ffff2f473c0) at src/libponyc/ast/ast.c:368
#11 0x0000000000431d1c in duplicate (parent=0x7ffff0492cc0, ast=0x7ffff2f49d80) at src/libponyc/ast/ast.c:368
#12 0x0000000000431d1c in duplicate (parent=0x7ffff0492cc0, ast=0x7ffff2f4a080) at src/libponyc/ast/ast.c:368
#13 0x0000000000431d1c in duplicate (parent=0x7ffff0492cc0, ast=0x7ffff2f4a7c0) at src/libponyc/ast/ast.c:368
#14 0x0000000000431d1c in duplicate (parent=0x7ffff0492cc0, ast=0x7ffff2f4a780) at src/libponyc/ast/ast.c:368
#15 0x0000000000431c7c in duplicate (parent=0x0, ast=0x7ffff2f4a6c0) at src/libponyc/ast/ast.c:359
#16 0x0000000000431b4c in ast_dup (ast=0x7ffff2f4a6c0) at src/libponyc/ast/ast.c:452
#17 0x00000000004e11f4 in viewpoint_replace (ast=0x7ffff2f4a6c0, target=0x7ffff0534b40, with=0x7ffff0562480) at src/libponyc/type/viewpoint.c:388
#18 0x00000000004e1545 in viewpoint_replacethis (ast=0x7ffff2f4a6c0, with=0x7ffff0562480) at src/libponyc/type/viewpoint.c:396
#19 0x00000000004f2c9a in lookup_nominal (opt=0x7fffffffe258, from=0x7ffff0562480, orig=0x7ffff0562480, type=0x7ffff0562480, name=0x7ffff3527f40 "create", errors=true)
    at src/libponyc/type/lookup.c:161
#20 0x00000000004f20c4 in lookup_base (opt=0x7fffffffe258, from=0x7ffff0562480, orig=0x7ffff0562480, type=0x7ffff0562480, name=0x7ffff3527f40 "create", errors=true)
    at src/libponyc/type/lookup.c:355
#21 0x00000000004f1f37 in lookup (opt=0x7fffffffe258, from=0x7ffff0562480, type=0x7ffff0562480, name=0x7ffff3527f40 "create") at src/libponyc/type/lookup.c:384
#22 0x0000000000485cc6 in genexe (c=0x7fffffffdda8, program=0x7ffff352fd40) at src/libponyc/codegen/genexe.c:382
#23 0x000000000046b47b in codegen (program=0x7ffff352fd40, opt=0x7fffffffe258) at src/libponyc/codegen/codegen.c:1000
#24 0x000000000044b4c3 in generate_passes (program=0x7ffff352fd40, options=0x7fffffffe258) at src/libponyc/pass/pass.c:291
#25 0x000000000043099d in compile_package (path=0x50cd5e ".", opt=0x7fffffffe258, print_program_ast=false, print_package_ast=false) at src/ponyc/main.c:245
#26 0x00000000004307d4 in main (argc=1, argv=0x7fffffffe3c8) at src/ponyc/main.c:367

It looks like the annotation node gets a type assigned to it. It doesn't happen when annotating a type declaration, only when annotating an expression.

According to git bisect, this bug was introduced in f788bb9.

[jemc]

Yep, this assert was introduced in #1649, but the weird behaviour of the annotation being assigned a type may have existed before the assert was present.

Is there any legitimate reason for an annotation node to get a type assigned to it? I think not, but just wanted to confirm with you.

[Praetonus]

I don't think there is. I tried to look where the annotation was getting a type assigned to it but I couldn't find the location.