Variable types -> metadata

crates/frontend/src/ast.rs

@@ -325,6 +325,7 @@ impl ir::ProgramInfo for ProgramInfo {
     type AssumptionMeta = Infallible;
     type RuleMeta = AstNode;
     type RuleBodyMeta = AstNode;
+    type VariableMeta = Infallible;
     type ExprMeta = AstNode;
     type BinaryOp = BinaryOpKind;
     type UnaryOp = ir::UnaryOpKind;

crates/ir/src/lib.rs

@@ -135,10 +135,10 @@ pub struct RuleBody<T: ProgramInfo> {
     /// Metadata for this rule body.
     pub meta: T::RuleBodyMeta,
 
-    /// The type of each variable.
+    /// The metadata for each variable.
     ///
     /// Also defines the upper bound on valid variable indices.
-    pub vars: Vec<Type>,
+    pub vars: Vec<T::VariableMeta>,
 
     /// Maps relation indices to the IDs of loaded relations.
     pub loaded: Vec<T::RelationLabel>,
@@ -435,6 +435,9 @@ pub trait ProgramInfo {
     /// Metadata for a rule body.
     type RuleBodyMeta: Info;
 
+    /// Metadata for each variable in a rule body.
+    type VariableMeta: Info;
+
     /// Metadata for each expression tree node.
     type ExprMeta: Info;
 
@@ -464,6 +467,7 @@ macro_rules! def_bound_info {
             AssumptionMeta: $bounds,
             RuleMeta: $bounds,
             RuleBodyMeta: $bounds,
+            VariableMeta: $bounds,
             ExprMeta: $bounds,
             BinaryOp: $bounds,
             UnaryOp: $bounds,
@@ -479,6 +483,7 @@ macro_rules! def_bound_info {
                 AssumptionMeta: $bounds,
                 RuleMeta: $bounds,
                 RuleBodyMeta: $bounds,
+                VariableMeta: $bounds,
                 ExprMeta: $bounds,
                 BinaryOp: $bounds,
                 UnaryOp: $bounds,