astgen: fix structInitExpr rvalue, RL handling, sentinel coercion, and empty init

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

astgen.c

@@ -4044,8 +4044,72 @@ static uint32_t callExpr(
     return call_index + ZIR_REF_START_INDEX;
 }
 
+// structInitExprAnon (AstGen.zig:1865-1893).
+// Anonymous struct init using struct_init_anon instruction.
+static uint32_t structInitExprAnon(GenZir* gz, Scope* scope, uint32_t node,
+    const uint32_t* fields, uint32_t fields_len) {
+    AstGenCtx* ag = gz->astgen;
+    const Ast* tree = ag->tree;
+
+    ensureExtraCapacity(ag, 3 + fields_len * 2);
+    uint32_t payload_index = ag->extra_len;
+    ag->extra[ag->extra_len++] = node; // abs_node
+    ag->extra[ag->extra_len++] = ag->source_line; // abs_line
+    ag->extra[ag->extra_len++] = fields_len;
+    uint32_t items_start = ag->extra_len;
+    ag->extra_len += fields_len * 2;
+
+    for (uint32_t i = 0; i < fields_len; i++) {
+        uint32_t field_init = fields[i];
+        uint32_t name_token = firstToken(tree, field_init) - 2;
+        uint32_t str_index = identAsString(ag, name_token);
+        uint32_t init_ref = expr(gz, scope, field_init);
+        ag->extra[items_start + i * 2] = str_index;
+        ag->extra[items_start + i * 2 + 1] = init_ref;
+    }
+
+    return addPlNodePayloadIndex(
+        gz, ZIR_INST_STRUCT_INIT_ANON, node, payload_index);
+}
+
+// structInitExprTyped (AstGen.zig:1896-1931).
+// Typed struct init using struct_init or struct_init_ref instruction.
+static uint32_t structInitExprTyped(GenZir* gz, Scope* scope, uint32_t node,
+    const uint32_t* fields, uint32_t fields_len, uint32_t ty_inst,
+    bool is_ref) {
+    AstGenCtx* ag = gz->astgen;
+    const Ast* tree = ag->tree;
+
+    ensureExtraCapacity(ag, 3 + fields_len * 2);
+    uint32_t payload_index = ag->extra_len;
+    ag->extra[ag->extra_len++] = node; // abs_node
+    ag->extra[ag->extra_len++] = ag->source_line; // abs_line
+    ag->extra[ag->extra_len++] = fields_len;
+    uint32_t items_start = ag->extra_len;
+    ag->extra_len += fields_len * 2;
+
+    for (uint32_t i = 0; i < fields_len; i++) {
+        uint32_t field_init = fields[i];
+        uint32_t name_token = firstToken(tree, field_init) - 2;
+        uint32_t str_index = identAsString(ag, name_token);
+        uint32_t field_ty_inst = addPlNodeBin(gz,
+            ZIR_INST_STRUCT_INIT_FIELD_TYPE, field_init, ty_inst, str_index);
+        ResultLoc elem_rl = { .tag = RL_COERCED_TY,
+            .data = field_ty_inst,
+            .src_node = 0,
+            .ctx = RI_CTX_NONE };
+        uint32_t init_ref = exprRl(gz, scope, elem_rl, field_init);
+        ag->extra[items_start + i * 2]
+            = field_ty_inst - ZIR_REF_START_INDEX; // .toIndex()
+        ag->extra[items_start + i * 2 + 1] = init_ref;
+    }
+
+    ZirInstTag init_tag
+        = is_ref ? ZIR_INST_STRUCT_INIT_REF : ZIR_INST_STRUCT_INIT;
+    return addPlNodePayloadIndex(gz, init_tag, node, payload_index);
+}
+
 // --- structInitExpr (AstGen.zig:1674) ---
-// Simplified: handles .{} (empty tuple), .{.a = b} (anon init).
 static uint32_t structInitExpr(
     GenZir* gz, Scope* scope, ResultLoc rl, uint32_t node) {
     AstGenCtx* ag = gz->astgen;
@@ -4118,7 +4182,15 @@ static uint32_t structInitExpr(
         if (rl.tag == RL_DISCARD) {
             return ZIR_REF_VOID_VALUE;
         }
-        return ZIR_REF_EMPTY_TUPLE;
+        if (rl.tag == RL_PTR) {
+            // AstGen.zig:1691-1696.
+            uint32_t ty_inst = rlResultType(gz, rl, node);
+            uint32_t val = addUnNode(
+                gz, ZIR_INST_STRUCT_INIT_EMPTY_RESULT, ty_inst, node);
+            return rvalue(gz, rl, val, node);
+        }
+        // RL_NONE, RL_REF, RL_INFERRED_PTR (AstGen.zig:1697-1699).
+        return rvalue(gz, rl, ZIR_REF_EMPTY_TUPLE, node);
     }
 
     // Pre-register all field names to match upstream string ordering.
@@ -4130,8 +4202,46 @@ static uint32_t structInitExpr(
     }
 
     if (type_expr_node == 0 && fields_len > 0) {
-        // structInitExprPtr for RL_PTR (AstGen.zig:1843-1846, 1934-1964).
+        // Anonymous struct init with fields (AstGen.zig:1821-1861).
-        if (rl.tag == RL_PTR) {
+        switch (rl.tag) {
+        case RL_NONE:
+            // structInitExprAnon (AstGen.zig:1822, 1865-1893).
+            return structInitExprAnon(gz, scope, node, fields, fields_len);
+        case RL_DISCARD: {
+            // Even if discarding we must perform side-effects
+            // (AstGen.zig:1823-1828).
+            for (uint32_t i = 0; i < fields_len; i++)
+                exprRl(gz, scope, RL_DISCARD_VAL, fields[i]);
+            return ZIR_REF_VOID_VALUE;
+        }
+        case RL_REF: {
+            // structInitExprAnon + ref (AstGen.zig:1830-1833).
+            uint32_t result
+                = structInitExprAnon(gz, scope, node, fields, fields_len);
+            return addUnTok(gz, ZIR_INST_REF, result, firstToken(tree, node));
+        }
+        case RL_REF_COERCED_TY: {
+            // Get elem type, validate, structInitExprTyped(is_ref=true)
+            // (AstGen.zig:1834-1837).
+            uint32_t result_ty_inst
+                = addUnNode(gz, ZIR_INST_ELEM_TYPE, rl.data, node);
+            addUnNode(gz, ZIR_INST_VALIDATE_STRUCT_INIT_RESULT_TY,
+                result_ty_inst, node);
+            return structInitExprTyped(
+                gz, scope, node, fields, fields_len, result_ty_inst, true);
+        }
+        case RL_TY:
+        case RL_COERCED_TY: {
+            // validate_struct_init_result_ty +
+            // structInitExprTyped(is_ref=false) (AstGen.zig:1839-1841).
+            uint32_t ty_inst = rl.data;
+            addUnNode(
+                gz, ZIR_INST_VALIDATE_STRUCT_INIT_RESULT_TY, ty_inst, node);
+            return structInitExprTyped(
+                gz, scope, node, fields, fields_len, ty_inst, false);
+        }
+        case RL_PTR: {
+            // structInitExprPtr (AstGen.zig:1843-1846, 1934-1964).
             uint32_t struct_ptr_inst
                 = addUnNode(gz, ZIR_INST_OPT_EU_BASE_PTR_INIT, rl.data, node);
             // Block payload: body_len = fields_len.
@@ -4155,68 +4265,22 @@ static uint32_t structInitExpr(
                 ResultLoc ptr_rl = { .tag = RL_PTR,
                     .data = field_ptr,
                     .src_node = 0,
-                    .ctx = rl.ctx };
+                    .ctx = RI_CTX_NONE };
                 exprRl(gz, scope, ptr_rl, field_init);
             }
             addPlNodePayloadIndex(
                 gz, ZIR_INST_VALIDATE_PTR_STRUCT_INIT, node, payload_index);
             return ZIR_REF_VOID_VALUE;
         }
-        // Anonymous struct init with RL type (AstGen.zig:1706-1731).
+        case RL_INFERRED_PTR: {
-        if (rl.tag == RL_TY || rl.tag == RL_COERCED_TY) {
+            // Standard anon init + rvalue store (AstGen.zig:1847-1852).
-            uint32_t ty_inst = rl.data;
+            uint32_t struct_inst
-            // validate_struct_init_result_ty (AstGen.zig:1840).
+                = structInitExprAnon(gz, scope, node, fields, fields_len);
-            addUnNode(
+            return rvalue(gz, rl, struct_inst, node);
-                gz, ZIR_INST_VALIDATE_STRUCT_INIT_RESULT_TY, ty_inst, node);
-            // structInitExprTyped (AstGen.zig:1896-1931).
-            ensureExtraCapacity(ag, 3 + fields_len * 2);
-            uint32_t payload_index = ag->extra_len;
-            ag->extra[ag->extra_len++] = node;
-            ag->extra[ag->extra_len++] = ag->source_line;
-            ag->extra[ag->extra_len++] = fields_len;
-            uint32_t items_start = ag->extra_len;
-            ag->extra_len += fields_len * 2;
-            for (uint32_t i = 0; i < fields_len; i++) {
-                uint32_t field_init = fields[i];
-                uint32_t name_token = firstToken(tree, field_init) - 2;
-                uint32_t str_index = identAsString(ag, name_token);
-                uint32_t field_ty_inst
-                    = addPlNodeBin(gz, ZIR_INST_STRUCT_INIT_FIELD_TYPE,
-                        field_init, ty_inst, str_index);
-                ResultLoc elem_rl = {
-                    .tag = RL_COERCED_TY, .data = field_ty_inst, .src_node = 0
-                };
-                uint32_t init_ref = exprRl(gz, scope, elem_rl, field_init);
-                ag->extra[items_start + i * 2]
-                    = field_ty_inst - ZIR_REF_START_INDEX;
-                ag->extra[items_start + i * 2 + 1] = init_ref;
-            }
-            return addPlNodePayloadIndex(
-                gz, ZIR_INST_STRUCT_INIT, node, payload_index);
         }
-        // Anonymous struct init without RL type (AstGen.zig:1864).
-        // StructInitAnon payload: abs_node, abs_line, fields_len.
-        ensureExtraCapacity(ag, 3 + fields_len * 2);
-        uint32_t payload_index = ag->extra_len;
-        ag->extra[ag->extra_len++] = node; // abs_node
-        ag->extra[ag->extra_len++] = ag->source_line; // abs_line
-        ag->extra[ag->extra_len++] = fields_len;
-        // Reserve space for field entries.
-        uint32_t items_start = ag->extra_len;
-        ag->extra_len += fields_len * 2;
-
-        for (uint32_t i = 0; i < fields_len; i++) {
-            uint32_t field_init = fields[i];
-            // field name is 2 tokens before the field init's first token.
-            uint32_t name_token = firstToken(tree, field_init) - 2;
-            uint32_t str_index = identAsString(ag, name_token);
-            uint32_t init_ref = expr(gz, scope, field_init);
-            ag->extra[items_start + i * 2] = str_index;
-            ag->extra[items_start + i * 2 + 1] = init_ref;
         }
-
+        SET_ERROR(ag);
-        return addPlNodePayloadIndex(
+        return ZIR_REF_VOID_VALUE;
-            gz, ZIR_INST_STRUCT_INIT_ANON, node, payload_index);
     }
 
     // Typed init: evaluate type, emit struct_init_empty or struct_init.
@@ -4246,7 +4310,7 @@ static uint32_t structInitExpr(
                 uint32_t elem_type_node
                     = tree->extra_data.arr[type_nd.rhs + 1];
                 uint32_t elem_type = typeExpr(gz, scope, elem_type_node);
-                ResultLoc sent_rl = { .tag = RL_COERCED_TY,
+                ResultLoc sent_rl = { .tag = RL_TY,
                     .data = elem_type,
                     .src_node = 0,
                     .ctx = RI_CTX_NONE };
@@ -4270,41 +4334,15 @@ static uint32_t structInitExpr(
     if (type_expr_node != 0 && fields_len > 0) {
         uint32_t ty_inst = typeExpr(gz, scope, type_expr_node);
         addUnNode(gz, ZIR_INST_VALIDATE_STRUCT_INIT_TY, ty_inst, node);
-
+        // Upstream: .ref => structInitExprTyped(is_ref=true)
-        // structInitExprTyped (AstGen.zig:1896-1931).
+        //           else => rvalue(structInitExprTyped(is_ref=false))
-        // StructInit payload: abs_node, abs_line, fields_len.
+        if (rl.tag == RL_REF) {
-        ensureExtraCapacity(ag, 3 + fields_len * 2);
+            return structInitExprTyped(
-        uint32_t payload_index = ag->extra_len;
+                gz, scope, node, fields, fields_len, ty_inst, true);
-        ag->extra[ag->extra_len++] = node; // abs_node
-        ag->extra[ag->extra_len++] = ag->source_line; // abs_line
-        ag->extra[ag->extra_len++] = fields_len;
-        // Reserve space for field items (field_type + init each).
-        uint32_t items_start = ag->extra_len;
-        ag->extra_len += fields_len * 2;
-
-        for (uint32_t i = 0; i < fields_len; i++) {
-            uint32_t field_init = fields[i];
-            uint32_t name_token = firstToken(tree, field_init) - 2;
-            uint32_t str_index = identAsString(ag, name_token);
-            // struct_init_field_type (AstGen.zig:1918-1921).
-            uint32_t field_ty_inst
-                = addPlNodeBin(gz, ZIR_INST_STRUCT_INIT_FIELD_TYPE, field_init,
-                    ty_inst, str_index);
-            // Evaluate init with coerced_ty (AstGen.zig:1924).
-            ResultLoc elem_rl = { .tag = RL_COERCED_TY,
-                .data = field_ty_inst,
-                .src_node = 0,
-                .ctx = rl.ctx };
-            uint32_t init_ref = exprRl(gz, scope, elem_rl, field_init);
-            ag->extra[items_start + i * 2]
-                = field_ty_inst - ZIR_REF_START_INDEX; // .toIndex()
-            ag->extra[items_start + i * 2 + 1] = init_ref;
         }
-
+        uint32_t struct_inst = structInitExprTyped(
-        bool is_ref = (RL_IS_REF(rl));
+            gz, scope, node, fields, fields_len, ty_inst, false);
-        ZirInstTag init_tag
+        return rvalue(gz, rl, struct_inst, node);
-            = is_ref ? ZIR_INST_STRUCT_INIT_REF : ZIR_INST_STRUCT_INIT;
-        return addPlNodePayloadIndex(gz, init_tag, node, payload_index);
     }
 
     SET_ERROR(ag);