mpl/conformance/DIVERGENCES.md

DIVERGENCES — where the two parsers disagree

Each entry is a minimized program that one parser accepts and the other rejects (JS = the parse phase of js/mpl.js; ANTLR = the grammar via ./gradlew parseCheck). Divergences are recorded, never auto-fixed — which parser is right is a ratification question for Stage 3. Rulings happen in JUDGMENT_CALLS.md.

Entries below are appended by conformance/harness/fuzz.mjs (deterministic: seed and index reproduce the original program), except where a different source is noted.

Divergence (found during C3 corpus construction)

✎ "drop\qme";

• JS interpreter: accepts (prints dropqme — an unknown string escape drops the backslash silently)
• ANTLR grammar: rejects (token recognition error at: '"drop\q')
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 49)

• JS interpreter: rejects (err_unexpected at 1:1)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 11)

"a\zb"

• JS interpreter: accepts (runs)
• ANTLR grammar: rejects (1:0: token recognition error at: '"a\z')
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 86)

((f);)

• JS interpreter: rejects (err_expect at 1:5)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 247)

(42;)

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 119)

(a;)

• JS interpreter: rejects (err_expect at 1:3)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 9)

(f∘g)

• JS interpreter: rejects (err_expect at 1:3)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 144)

({"",(a)})

• JS interpreter: rejects (err_expect at 1:5)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 456)

({"a b",2})

• JS interpreter: rejects (err_expect at 1:8)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 182)

({(007),true})

• JS interpreter: rejects (err_expect at 1:8)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 284)

({(1),⊥})

• JS interpreter: rejects (err_expect at 1:6)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 276)

({5,"a b"})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 427)

({b:y})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 101)

({c,0.5})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 425)

({g:⊥})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 194)

({x,(5)})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 212)

({y:"hi"})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 25)

({y:0})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 347)

({{},{}})

• JS interpreter: rejects (err_expect at 1:5)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 52)

({λ})

• JS interpreter: rejects (err_expect at 1:4)
• ANTLR grammar: accepts (parses)
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 76)

λ(b):(42)

• JS interpreter: accepts (runs)
• ANTLR grammar: rejects (1:4: mismatched input ':' expecting {, ';', PARALLEL, LEFTARROW, IMPLIES, OR, AND, '=', NEQ, '<', '>', LEQ, GEQ, APPROX, SIM, '+', '-', TIMES, DIV, AST, COMPOSE, DEFINITION, HANDLE, ALLOC, RELEASE, '(', '|', MIDDOT})
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 13)

λ(f):42

• JS interpreter: accepts (runs)
• ANTLR grammar: rejects (1:4: mismatched input ':' expecting {, ';', PARALLEL, LEFTARROW, IMPLIES, OR, AND, '=', NEQ, '<', '>', LEQ, GEQ, APPROX, SIM, '+', '-', TIMES, DIV, AST, COMPOSE, DEFINITION, HANDLE, ALLOC, RELEASE, '(', '|', MIDDOT})
• RULING: pending (see JUDGMENT_CALLS.md)

Divergence (fuzz seed 20260709, index 29)

λ(y):f

• JS interpreter: accepts (runs)
• ANTLR grammar: rejects (1:4: mismatched input ':' expecting {, ';', PARALLEL, LEFTARROW, IMPLIES, OR, AND, '=', NEQ, '<', '>', LEQ, GEQ, APPROX, SIM, '+', '-', TIMES, DIV, AST, COMPOSE, DEFINITION, HANDLE, ALLOC, RELEASE, '(', '|', MIDDOT})
• RULING: pending (see JUDGMENT_CALLS.md)