Refactor CIR regions to be in a separate array

src/cache.zig

@@ -284,10 +284,11 @@ test "NodeStore cache round-trip" {
         .data_1 = 42,
         .data_2 = 100,
         .data_3 = 200,
-        .region = .{ .start = .{ .offset = 0 }, .end = .{ .offset = 10 } },
         .tag = .expr_string,
     };
     const expr_idx = store.nodes.append(store.gpa, expr_node);
+    const region = base.Region{ .start = .{ .offset = 0 }, .end = .{ .offset = 10 } };
+    _ = store.regions.append(store.gpa, region);
 
     try store.extra_data.append(store.gpa, 1234);
     try store.extra_data.append(store.gpa, 5678);

src/check/canonicalize/CIR.zig

@@ -466,8 +466,8 @@ fn formatPatternIdxNode(gpa: std.mem.Allocator, pattern_idx: Pattern.Idx) SExpr
     return node;
 }
 
-test "Node is 24 bytes" {
-    try testing.expectEqual(24, @sizeOf(Node));
+test "Node is 16 bytes" {
+    try testing.expectEqual(16, @sizeOf(Node));
 }
 
 /// A working representation of a record field
@@ -710,7 +710,7 @@ pub const Def = struct {
 
         var node = SExpr.init(gpa, kind);
 
-        var pattern_node = ir.store.getPattern(self.pattern).toSExpr(ir);
+        var pattern_node = ir.store.getPattern(self.pattern).toSExpr(ir, self.pattern);
         node.appendNode(gpa, &pattern_node);
 
         var expr_node = ir.store.getExpr(self.expr).toSExpr(ir);
@@ -1075,10 +1075,10 @@ pub fn toSexprTypes(ir: *CIR, maybe_expr_idx: ?Expr.Idx, source: []const u8) SEx
             // Extract identifier name from the pattern (assuming it's an assign pattern)
             const pattern = ir.store.getPattern(def.pattern);
             switch (pattern) {
-                .assign => |assign_pat| {
+                .assign => |_| {
                     var def_node = SExpr.init(gpa, "patt");
 
-                    ir.appendRegionInfoToSexprNodeFromRegion(&def_node, assign_pat.region);
+                    ir.appendRegionInfoToSexprNode(&def_node, def_idx);
 
                     // Get the type variable for this definition
                     // Each definition has a type_var at its node index which represents the type of the definition

src/check/canonicalize/Expression.zig

@@ -715,7 +715,7 @@ pub const Expr = union(enum) {
                 // Handle args span
                 var args_node = SExpr.init(gpa, "args");
                 for (ir.store.slicePatterns(lambda_expr.args)) |arg_idx| {
-                    var pattern_node = ir.store.getPattern(arg_idx).toSExpr(ir);
+                    var pattern_node = ir.store.getPattern(arg_idx).toSExpr(ir, arg_idx);
                     args_node.appendNode(gpa, &pattern_node);
                 }
                 node.appendNode(gpa, &args_node);
@@ -837,7 +837,7 @@ pub const Expr = union(enum) {
                 for (patterns_slice) |branch_pat_idx| {
                     const branch_pat = ir.store.getMatchBranchPattern(branch_pat_idx);
                     const pattern = ir.store.getPattern(branch_pat.pattern);
-                    var pattern_sexpr = pattern.toSExpr(ir);
+                    var pattern_sexpr = pattern.toSExpr(ir, branch_pat.pattern);
                     pattern_sexpr.appendBoolAttr(gpa, "degenerate", branch_pat.degenerate);
                     patterns_node.appendNode(gpa, &pattern_sexpr);
                 }

src/check/canonicalize/Node.zig

@@ -12,7 +12,6 @@ const collections = @import("../../collections.zig");
 data_1: u32,
 data_2: u32,
 data_3: u32,
-region: base.Region,
 tag: Tag,
 
 /// A list of nodes.