fix(parser): bind source-counter-gated rider pronouns to the source (Gemstone Mine #6507)

crates/engine/src/parser/oracle_effect/mod.rs

@@ -238,12 +238,53 @@ pub(crate) fn resolve_it_pronoun(ctx: &mut ParseContext) -> TargetFilter {
     }
 }
 
+/// CR 122.1 + CR 608.2k: true when the expression reads a counter total on the
+/// ability's own source object ("counters on ~" / "counters on this land").
+/// Recognizes `CountersOn { scope: Source }` through the arithmetic wrappers so
+/// a wrapped threshold still registers as source-referential. Mirrors the
+/// exhaustive wrapper walk of `quantity_expr_uses_recipient`
+/// (`game/quantity.rs`) so the compiler flags any future `QuantityExpr` variant.
+fn quantity_expr_reads_source_counters(expr: &QuantityExpr) -> bool {
+    match expr {
+        QuantityExpr::Fixed { .. } => false,
+        QuantityExpr::Ref { qty } => matches!(
+            qty,
+            QuantityRef::CountersOn {
+                scope: ObjectScope::Source,
+                ..
+            }
+        ),
+        QuantityExpr::DivideRounded { inner, .. }
+        | QuantityExpr::Offset { inner, .. }
+        | QuantityExpr::ClampMin { inner, .. }
+        | QuantityExpr::Multiply { inner, .. } => quantity_expr_reads_source_counters(inner),
+        QuantityExpr::Sum { exprs } | QuantityExpr::Max { exprs } => {
+            exprs.iter().any(quantity_expr_reads_source_counters)
+        }
+        QuantityExpr::UpTo { max } => quantity_expr_reads_source_counters(max),
+        QuantityExpr::Power { exponent, .. } => quantity_expr_reads_source_counters(exponent),
+        QuantityExpr::Difference { left, right } => {
+            quantity_expr_reads_source_counters(left) || quantity_expr_reads_source_counters(right)
+        }
+    }
+}
+
 fn condition_refs_source_object(condition: &AbilityCondition) -> bool {
     match condition {
         AbilityCondition::SourceMatchesFilter { .. }
         | AbilityCondition::SourceEnteredThisTurn
         | AbilityCondition::SourceIsTapped
         | AbilityCondition::SourceAttachedToCreature => true,
+        // CR 122.1: a counter-threshold gate scoped to the SOURCE
+        // ("if there are no mining counters on this land", "if it has six or
+        // more quest counters on it") refers to the ability's own untargeted
+        // source object, so a bare "it" in the gated body anaphors to the
+        // source permanent — Gemstone Mine / the Mercadian depletion lands
+        // (issue #6507), Tourach's Gate, Daredevil Dragster, Last Light of
+        // Durin's Day.
+        AbilityCondition::QuantityCheck { lhs, rhs, .. } => {
+            quantity_expr_reads_source_counters(lhs) || quantity_expr_reads_source_counters(rhs)
+        }
         AbilityCondition::Not { condition }
         | AbilityCondition::ConditionInstead { inner: condition } => {
             condition_refs_source_object(condition)
@@ -255,6 +296,64 @@ fn condition_refs_source_object(condition: &AbilityCondition) -> bool {
     }
 }
 
+fn generic_effect_has_source_counter_quantity_condition(effect: &Effect) -> bool {
+    matches!(
+        effect,
+        Effect::GenericEffect {
+            static_abilities,
+            ..
+        } if static_abilities.iter().any(|definition| {
+            matches!(
+                &definition.condition,
+                Some(StaticCondition::QuantityComparison {
+                    lhs: QuantityExpr::Ref {
+                        qty: QuantityRef::CountersOn {
+                            scope: ObjectScope::Source,
+                            ..
+                        },
+                    },
+                    ..
+                })
+            )
+        })
+    )
+}
+
+/// CR 122.1 + CR 608.2c: The bare recipient pronoun in a leading
+/// `if it has … counter on it,` gate follows the prior chosen target. This is
+/// the sole authority for that lexical form after its static definitions have
+/// been finalized; explicit source subjects never reach this helper.
+fn rewrite_generic_effect_source_counter_quantity_condition_to_recipient(effect: &mut Effect) {
+    let Effect::GenericEffect {
+        static_abilities, ..
+    } = effect
+    else {
+        return;
+    };
+
+    for definition in static_abilities {
+        let is_source_counter_quantity = matches!(
+            &definition.condition,
+            Some(StaticCondition::QuantityComparison {
+                lhs: QuantityExpr::Ref {
+                    qty: QuantityRef::CountersOn {
+                        scope: ObjectScope::Source,
+                        ..
+                    },
+                },
+                ..
+            })
+        );
+        if !is_source_counter_quantity {
+            continue;
+        }
+        definition.condition = definition
+            .condition
+            .take()
+            .map(crate::parser::oracle_static::rebind_source_object_quantities_to_recipient);
+    }
+}
+
 fn condition_refs_cost_paid_object(condition: &AbilityCondition) -> bool {
     match condition {
         AbilityCondition::CostPaidObjectMatchesFilter { .. } => true,
@@ -30137,6 +30236,7 @@ pub(crate) fn parse_effect_chain_ir(
             (None, Some(unless_cond)) => Some(unless_cond),
             (existing, None) => existing,
         };
+        let prior_typed_referent = chain_has_prior_typed_referent(builder.clauses(), false);
         // CR 701.34a + CR 122.1: keep the whole "for each kind of counter on
         // target permanent or player, give … another counter of that kind"
         // clause intact so the targeted-proliferate recognizer in
@@ -30474,7 +30574,14 @@ pub(crate) fn parse_effect_chain_ir(
         }
         .or_else(|| ctx.actor.clone());
         let if_you_do_anchor = if_you_do_object_anchor(builder.clauses(), &condition);
-        let chunk_subject = if condition.as_ref().is_some_and(condition_refs_source_object) {
+        // CR 608.2k: An `AbilityCondition` source-counter gate binds a bare
+        // body pronoun to the source only when no prior clause chose a typed
+        // target. This preserves the depletion-land / counter-rider class;
+        // GenericEffect static counter gates are rebound after their static
+        // definitions are finalized below.
+        let binds_source_counter_pronoun =
+            condition.as_ref().is_some_and(condition_refs_source_object) && !prior_typed_referent;
+        let chunk_subject = if binds_source_counter_pronoun {
             Some(TargetFilter::SelfRef)
         } else {
             if_you_do_anchor.clone().or_else(|| ctx.subject.clone())
@@ -30487,9 +30594,8 @@ pub(crate) fn parse_effect_chain_ir(
         // this flag when the outer chain has such a referent (Brilliance Unleashed).
         // It is false on every top-level and non-else nested parse, so this OR is a
         // no-op for all pre-existing cards.
-        let parent_target_available = ctx.parent_target_available
-            || if_you_do_anchor.is_some()
-            || chain_has_prior_typed_referent(builder.clauses(), false);
+        let parent_target_available =
+            ctx.parent_target_available || if_you_do_anchor.is_some() || prior_typed_referent;
         // CR 608.2c + CR 601.2a: a strict subset of `parent_target_available`
         // restricted to chosen-target referents (Emry), excluding impulse
         // publishers (Territorial Bruntar's `ExileFromTopUntil`). An "if you
@@ -31047,6 +31153,16 @@ pub(crate) fn parse_effect_chain_ir(
         // carries the caster default (Controller). Per D-04, this is parse-time
         // pronoun resolution that belongs in IR production.
         let mut clause = clause;
+        if prior_typed_referent
+            && generic_effect_has_source_counter_quantity_condition(&clause.effect)
+            && crate::parser::oracle_nom::condition::is_leading_if_bare_recipient_counter_condition(
+                normalized_text,
+            )
+        {
+            rewrite_generic_effect_source_counter_quantity_condition_to_recipient(
+                &mut clause.effect,
+            );
+        }
         // CR 608.2c: Bind a bare anaphoric "the difference" count placeholder in
         // this clause against the two operands its own leading `QuantityCheck`
         // condition established ("If the discovered card's mana value is less than
@@ -31266,7 +31382,11 @@ pub(crate) fn parse_effect_chain_ir(
         // which is scoped to exactly the reported bug class.
         if condition.is_some()
             && !is_distributed_chunk
-            && !condition.as_ref().is_some_and(condition_refs_source_object)
+            // CR 608.2k: only a GENUINE source-counter gate (no prior chosen
+            // target — see `binds_source_counter_pronoun`) keeps the SelfRef
+            // binding; a mis-scoped bare "it" over a prior typed target
+            // (Revelation of Power) still rewrites to the parent target here.
+            && !binds_source_counter_pronoun
             && !builder.is_empty()
             && has_anaphoric_reference(&text_lower)
             && !matches!(if_you_do_anchor, Some(TargetFilter::SelfRef))

crates/engine/src/parser/oracle_effect/tests.rs

@@ -29361,6 +29361,146 @@ fn resolve_it_pronoun_any_subject() {
     assert_eq!(resolve_it_pronoun(&mut ctx), TargetFilter::SelfRef);
 }
 
+/// Issue #6507 (CR 122.1): `condition_refs_source_object` must
+/// recognize a source-scoped counter-threshold `QuantityCheck` ("if there are
+/// no mining counters on this land") as source-referential — that gate is what
+/// threads `SelfRef` as the chunk subject so the rider's bare "it" binds to
+/// the source. Adjacent-variant hostiles: `Target`/`Recipient`-scoped counter
+/// reads (the deliberately excluded "if that creature has … counters" class)
+/// must stay non-source-referential.
+#[test]
+fn condition_refs_source_object_source_counter_quantity_check() {
+    fn counters_check(scope: ObjectScope) -> AbilityCondition {
+        AbilityCondition::QuantityCheck {
+            lhs: QuantityExpr::Ref {
+                qty: QuantityRef::CountersOn {
+                    scope,
+                    counter_type: Some(crate::types::counter::parse_counter_type("mining")),
+                },
+            },
+            comparator: Comparator::EQ,
+            rhs: QuantityExpr::Fixed { value: 0 },
+        }
+    }
+
+    // Positive: source-scoped counter threshold (the Gemstone Mine class).
+    assert!(condition_refs_source_object(&counters_check(
+        ObjectScope::Source
+    )));
+    // Wrapped-expression positive: the walker must see through arithmetic
+    // wrappers (`Offset { CountersOn { Source } }` still reads the source).
+    assert!(condition_refs_source_object(
+        &AbilityCondition::QuantityCheck {
+            lhs: QuantityExpr::Offset {
+                inner: Box::new(QuantityExpr::Ref {
+                    qty: QuantityRef::CountersOn {
+                        scope: ObjectScope::Source,
+                        counter_type: None,
+                    },
+                }),
+                offset: 1,
+            },
+            comparator: Comparator::GE,
+            rhs: QuantityExpr::Fixed { value: 2 },
+        }
+    ));
+    // Existing wrapper recursion still applies to the new arm.
+    assert!(condition_refs_source_object(&AbilityCondition::Not {
+        condition: Box::new(counters_check(ObjectScope::Source)),
+    }));
+    assert!(condition_refs_source_object(&AbilityCondition::And {
+        conditions: vec![
+            AbilityCondition::IsYourTurn,
+            counters_check(ObjectScope::Source),
+        ],
+    }));
+    // `QuantityCheck` must inspect both sides of the comparison, not only the
+    // customary left-hand counter threshold.
+    assert!(condition_refs_source_object(
+        &AbilityCondition::QuantityCheck {
+            lhs: QuantityExpr::Fixed { value: 0 },
+            comparator: Comparator::EQ,
+            rhs: QuantityExpr::Ref {
+                qty: QuantityRef::CountersOn {
+                    scope: ObjectScope::Source,
+                    counter_type: None,
+                },
+            },
+        }
+    ));
+
+    // Adjacent-variant hostiles: target-/recipient-scoped counter reads keep
+    // their current (non-source) binding.
+    assert!(!condition_refs_source_object(&counters_check(
+        ObjectScope::Target
+    )));
+    assert!(!condition_refs_source_object(&counters_check(
+        ObjectScope::Recipient
+    )));
+    // A QuantityCheck with no counter read at all stays non-source-referential.
+    assert!(!condition_refs_source_object(
+        &AbilityCondition::QuantityCheck {
+            lhs: QuantityExpr::Ref {
+                qty: QuantityRef::HandSize {
+                    player: PlayerScope::Controller,
+                },
+            },
+            comparator: Comparator::GE,
+            rhs: QuantityExpr::Fixed { value: 7 },
+        }
+    ));
+
+    // Two-operand wrapper arms: the walker must recurse into BOTH branches so a
+    // source-counter read hidden in either operand still registers, and a
+    // wrapper with neither operand reading the source stays negative. These
+    // arms were previously undriven by this test (only Ref/Offset were).
+    let source_read = QuantityExpr::Ref {
+        qty: QuantityRef::CountersOn {
+            scope: ObjectScope::Source,
+            counter_type: None,
+        },
+    };
+    // Sum { exprs } — recurse via `.any(..)`: source read in one operand → true.
+    assert!(condition_refs_source_object(
+        &AbilityCondition::QuantityCheck {
+            lhs: QuantityExpr::Sum {
+                exprs: vec![QuantityExpr::Fixed { value: 1 }, source_read.clone()],
+            },
+            comparator: Comparator::GE,
+            rhs: QuantityExpr::Fixed { value: 2 },
+        }
+    ));
+    // Difference { left, right } — recurse via `left || right`: source read on
+    // the right operand alone still registers.
+    assert!(condition_refs_source_object(
+        &AbilityCondition::QuantityCheck {
+            lhs: QuantityExpr::Difference {
+                left: Box::new(QuantityExpr::Fixed { value: 3 }),
+                right: Box::new(source_read.clone()),
+            },
+            comparator: Comparator::EQ,
+            rhs: QuantityExpr::Fixed { value: 0 },
+        }
+    ));
+    // Neither-operand-source Sum stays negative (no false positive).
+    assert!(!condition_refs_source_object(
+        &AbilityCondition::QuantityCheck {
+            lhs: QuantityExpr::Sum {
+                exprs: vec![
+                    QuantityExpr::Fixed { value: 1 },
+                    QuantityExpr::Ref {
+                        qty: QuantityRef::HandSize {
+                            player: PlayerScope::Controller,
+                        },
+                    },
+                ],
+            },
+            comparator: Comparator::GE,
+            rhs: QuantityExpr::Fixed { value: 2 },
+        }
+    ));
+}
+
 // --- Suffix condition extraction tests ---
 
 #[test]

crates/engine/src/parser/oracle_nom/condition.rs

@@ -12,6 +12,7 @@ use nom::multi::many0;
 use nom::sequence::{preceded, terminated};
 use nom::Parser;
 
+use super::bridge::nom_on_lower;
 use super::error::{oracle_err, OracleError, OracleResult};
 use super::primitives::{
     parse_article, parse_color, parse_keyword_name, parse_mana_cost, parse_number,
@@ -2223,6 +2224,20 @@ fn parse_has_counters_axes(
     Ok((rest, (subject, counters, minimum, maximum)))
 }
 
+/// CR 122.1 + CR 608.2c: identifies only a leading `if it has … counter on it,`
+/// condition. The generic counter-condition parser resolves bare `it` to the
+/// source by default; effect-chain parsing uses this narrow lexical fact to
+/// rebind that condition when an earlier clause established a typed referent.
+/// Explicit source subjects (`~`, `this creature`, `this land`) deliberately do
+/// not match and retain their source scope.
+pub(crate) fn is_leading_if_bare_recipient_counter_condition(input: &str) -> bool {
+    let lower = input.to_lowercase();
+    nom_on_lower(input, &lower, |i| {
+        terminated(preceded(tag("if "), parse_has_counters_axes), tag(",")).parse(i)
+    })
+    .is_some_and(|((subject, ..), _)| matches!(subject, CounterConditionSubject::RecipientPronoun))
+}
+
 /// Subject axis for counter-has conditions. Accepts the canonical
 /// source-referential subjects, the bound pronoun `"it "`, and the
 /// demonstrative anaphor `"that creature/land/permanent "` used in
@@ -19052,6 +19067,25 @@ mod tests {
         );
     }
 
+    /// CR 122.1 + CR 608.2c: effect-chain parsing may rebind only the bare
+    /// recipient-pronoun form after an earlier typed target. Explicit source
+    /// and demonstrative-recipient subjects must remain distinguishable.
+    #[test]
+    fn leading_if_bare_recipient_counter_condition_is_narrow() {
+        assert!(is_leading_if_bare_recipient_counter_condition(
+            "If it has a counter on it, it gains flying"
+        ));
+        assert!(!is_leading_if_bare_recipient_counter_condition(
+            "If this creature has a counter on it, it gains flying"
+        ));
+        assert!(!is_leading_if_bare_recipient_counter_condition(
+            "If that creature has a counter on it, it gains flying"
+        ));
+        assert!(!is_leading_if_bare_recipient_counter_condition(
+            "If it is tapped, it gains flying"
+        ));
+    }
+
     /// CR 611.3a: the bound pronoun "it" in a self-referential combat-state gate
     /// binds to the source permanent. Intrepid Ace's "it isn't attacking or
     /// blocking" must parse to `Not(Or[SourceIsAttacking, SourceIsBlocking])`,

crates/engine/src/parser/oracle_static/mod.rs

@@ -92,7 +92,9 @@ mod shared;
 mod static_helpers;
 mod type_change;
 
-pub(crate) use shared::parse_commander_subject_filter_prefix;
+pub(crate) use shared::{
+    parse_commander_subject_filter_prefix, rebind_source_object_quantities_to_recipient,
+};
 
 pub(crate) use dispatch::is_speed_unlock_sentence;
 pub(crate) use dispatch::parse_may_look_at_face_down_filter;