Commit ca2a788a24

Andrew Kelley <andrew@ziglang.org>
2019-11-11 23:50:41
fully anonymous struct literals
1 parent 1bca8e6
Changed files (5)
src/all_types.hpp
@@ -1187,10 +1187,22 @@ bool fn_type_id_eql(FnTypeId *a, FnTypeId *b);
 static const uint32_t VECTOR_INDEX_NONE = UINT32_MAX;
 static const uint32_t VECTOR_INDEX_RUNTIME = UINT32_MAX - 1;
 
+struct InferredStructField {
+    ZigType *inferred_struct_type;
+    Buf *field_name;
+};
+
 struct ZigTypePointer {
     ZigType *child_type;
     ZigType *slice_parent;
 
+    // Anonymous struct literal syntax uses this when the result location has
+    // no type in it. This field is null if this pointer does not refer to
+    // a field of a currently-being-inferred struct type.
+    // When this is non-null, the pointer is pointing to the base of the inferred
+    // struct.
+    InferredStructField *inferred_struct_field;
+
     PtrLen ptr_len;
     uint32_t explicit_alignment; // 0 means use ABI alignment
 
@@ -1743,6 +1755,7 @@ struct TypeId {
     union {
         struct {
             ZigType *child_type;
+            InferredStructField *inferred_struct_field;
             PtrLen ptr_len;
             uint32_t alignment;
 
src/analyze.cpp
@@ -486,7 +486,7 @@ ZigType *get_fn_frame_type(CodeGen *g, ZigFn *fn) {
 ZigType *get_pointer_to_type_extra2(CodeGen *g, ZigType *child_type, bool is_const,
         bool is_volatile, PtrLen ptr_len, uint32_t byte_alignment,
         uint32_t bit_offset_in_host, uint32_t host_int_bytes, bool allow_zero,
-        uint32_t vector_index)
+        uint32_t vector_index, InferredStructField *inferred_struct_field)
 {
     assert(ptr_len != PtrLenC || allow_zero);
     assert(!type_is_invalid(child_type));
@@ -509,7 +509,7 @@ ZigType *get_pointer_to_type_extra2(CodeGen *g, ZigType *child_type, bool is_con
     TypeId type_id = {};
     ZigType **parent_pointer = nullptr;
     if (host_int_bytes != 0 || is_volatile || byte_alignment != 0 || ptr_len != PtrLenSingle ||
-        allow_zero || vector_index != VECTOR_INDEX_NONE)
+        allow_zero || vector_index != VECTOR_INDEX_NONE || inferred_struct_field != nullptr)
     {
         type_id.id = ZigTypeIdPointer;
         type_id.data.pointer.child_type = child_type;
@@ -521,6 +521,7 @@ ZigType *get_pointer_to_type_extra2(CodeGen *g, ZigType *child_type, bool is_con
         type_id.data.pointer.ptr_len = ptr_len;
         type_id.data.pointer.allow_zero = allow_zero;
         type_id.data.pointer.vector_index = vector_index;
+        type_id.data.pointer.inferred_struct_field = inferred_struct_field;
 
         auto existing_entry = g->type_table.maybe_get(type_id);
         if (existing_entry)
@@ -548,8 +549,15 @@ ZigType *get_pointer_to_type_extra2(CodeGen *g, ZigType *child_type, bool is_con
     }
     buf_resize(&entry->name, 0);
     if (host_int_bytes == 0 && byte_alignment == 0 && vector_index == VECTOR_INDEX_NONE) {
-        buf_appendf(&entry->name, "%s%s%s%s%s",
-                star_str, const_str, volatile_str, allow_zero_str, buf_ptr(&child_type->name));
+        if (inferred_struct_field == nullptr) {
+            buf_appendf(&entry->name, "%s%s%s%s%s",
+                    star_str, const_str, volatile_str, allow_zero_str, buf_ptr(&child_type->name));
+        } else {
+            buf_appendf(&entry->name, "(%s%s%s%s field '%s' of %s)",
+                    star_str, const_str, volatile_str, allow_zero_str,
+                    buf_ptr(inferred_struct_field->field_name),
+                    buf_ptr(&inferred_struct_field->inferred_struct_type->name));
+        }
     } else if (host_int_bytes == 0 && vector_index == VECTOR_INDEX_NONE) {
         buf_appendf(&entry->name, "%salign(%" PRIu32 ") %s%s%s%s", star_str, byte_alignment,
                 const_str, volatile_str, allow_zero_str, buf_ptr(&child_type->name));
@@ -606,6 +614,7 @@ ZigType *get_pointer_to_type_extra2(CodeGen *g, ZigType *child_type, bool is_con
     entry->data.pointer.host_int_bytes = host_int_bytes;
     entry->data.pointer.allow_zero = allow_zero;
     entry->data.pointer.vector_index = vector_index;
+    entry->data.pointer.inferred_struct_field = inferred_struct_field;
 
     if (parent_pointer) {
         *parent_pointer = entry;
@@ -620,12 +629,12 @@ ZigType *get_pointer_to_type_extra(CodeGen *g, ZigType *child_type, bool is_cons
         uint32_t bit_offset_in_host, uint32_t host_int_bytes, bool allow_zero)
 {
     return get_pointer_to_type_extra2(g, child_type, is_const, is_volatile, ptr_len,
-            byte_alignment, bit_offset_in_host, host_int_bytes, allow_zero, VECTOR_INDEX_NONE);
+            byte_alignment, bit_offset_in_host, host_int_bytes, allow_zero, VECTOR_INDEX_NONE, nullptr);
 }
 
 ZigType *get_pointer_to_type(CodeGen *g, ZigType *child_type, bool is_const) {
     return get_pointer_to_type_extra2(g, child_type, is_const, false, PtrLenSingle, 0, 0, 0, false,
-            VECTOR_INDEX_NONE);
+            VECTOR_INDEX_NONE, nullptr);
 }
 
 ZigType *get_optional_type(CodeGen *g, ZigType *child_type) {
@@ -2082,7 +2091,7 @@ static Error resolve_struct_type(CodeGen *g, ZigType *struct_type) {
     }
 
     assert(struct_type->data.structure.fields || struct_type->data.structure.src_field_count == 0);
-    assert(decl_node->type == NodeTypeContainerDecl);
+    assert(decl_node->type == NodeTypeContainerDecl || decl_node->type == NodeTypeContainerInitExpr);
 
     size_t field_count = struct_type->data.structure.src_field_count;
 
@@ -2670,7 +2679,6 @@ static Error resolve_struct_zero_bits(CodeGen *g, ZigType *struct_type) {
         return ErrorNone;
 
     AstNode *decl_node = struct_type->data.structure.decl_node;
-    assert(decl_node->type == NodeTypeContainerDecl);
 
     if (struct_type->data.structure.resolve_loop_flag_zero_bits) {
         if (struct_type->data.structure.resolve_status != ResolveStatusInvalid) {
@@ -2681,29 +2689,46 @@ static Error resolve_struct_zero_bits(CodeGen *g, ZigType *struct_type) {
         }
         return ErrorSemanticAnalyzeFail;
     }
-
     struct_type->data.structure.resolve_loop_flag_zero_bits = true;
 
-    assert(!struct_type->data.structure.fields);
-    size_t field_count = decl_node->data.container_decl.fields.length;
-    struct_type->data.structure.src_field_count = (uint32_t)field_count;
-    struct_type->data.structure.fields = allocate<TypeStructField>(field_count);
+    size_t field_count;
+    if (decl_node->type == NodeTypeContainerDecl) {
+        field_count = decl_node->data.container_decl.fields.length;
+        struct_type->data.structure.src_field_count = (uint32_t)field_count;
+
+        src_assert(struct_type->data.structure.fields == nullptr, decl_node);
+        struct_type->data.structure.fields = allocate<TypeStructField>(field_count);
+    } else if (decl_node->type == NodeTypeContainerInitExpr) {
+        src_assert(struct_type->data.structure.is_inferred, decl_node);
+        src_assert(struct_type->data.structure.fields != nullptr, decl_node);
+
+        field_count = struct_type->data.structure.src_field_count;
+    } else zig_unreachable();
+
     struct_type->data.structure.fields_by_name.init(field_count);
 
     Scope *scope = &struct_type->data.structure.decls_scope->base;
 
     size_t gen_field_index = 0;
     for (size_t i = 0; i < field_count; i += 1) {
-        AstNode *field_node = decl_node->data.container_decl.fields.at(i);
         TypeStructField *type_struct_field = &struct_type->data.structure.fields[i];
-        type_struct_field->name = field_node->data.struct_field.name;
-        type_struct_field->decl_node = field_node;
 
-        if (field_node->data.struct_field.type == nullptr) {
-            add_node_error(g, field_node, buf_sprintf("struct field missing type"));
-            struct_type->data.structure.resolve_status = ResolveStatusInvalid;
-            return ErrorSemanticAnalyzeFail;
-        }
+        AstNode *field_node;
+        if (decl_node->type == NodeTypeContainerDecl) {
+            field_node = decl_node->data.container_decl.fields.at(i);
+            type_struct_field->name = field_node->data.struct_field.name;
+            type_struct_field->decl_node = field_node;
+
+            if (field_node->data.struct_field.type == nullptr) {
+                add_node_error(g, field_node, buf_sprintf("struct field missing type"));
+                struct_type->data.structure.resolve_status = ResolveStatusInvalid;
+                return ErrorSemanticAnalyzeFail;
+            }
+        } else if (decl_node->type == NodeTypeContainerInitExpr) {
+            field_node = type_struct_field->decl_node;
+
+            src_assert(type_struct_field->type_entry != nullptr, field_node);
+        } else zig_unreachable();
 
         auto field_entry = struct_type->data.structure.fields_by_name.put_unique(type_struct_field->name, type_struct_field);
         if (field_entry != nullptr) {
@@ -2714,16 +2739,21 @@ static Error resolve_struct_zero_bits(CodeGen *g, ZigType *struct_type) {
             return ErrorSemanticAnalyzeFail;
         }
 
-        ConstExprValue *field_type_val = analyze_const_value(g, scope,
-                field_node->data.struct_field.type, g->builtin_types.entry_type, nullptr, LazyOkNoUndef);
-        if (type_is_invalid(field_type_val->type)) {
-            struct_type->data.structure.resolve_status = ResolveStatusInvalid;
-            return ErrorSemanticAnalyzeFail;
-        }
-        assert(field_type_val->special != ConstValSpecialRuntime);
-        type_struct_field->type_val = field_type_val;
-        if (struct_type->data.structure.resolve_status == ResolveStatusInvalid)
-            return ErrorSemanticAnalyzeFail;
+        ConstExprValue *field_type_val;
+        if (decl_node->type == NodeTypeContainerDecl) {
+            field_type_val = analyze_const_value(g, scope,
+                    field_node->data.struct_field.type, g->builtin_types.entry_type, nullptr, LazyOkNoUndef);
+            if (type_is_invalid(field_type_val->type)) {
+                struct_type->data.structure.resolve_status = ResolveStatusInvalid;
+                return ErrorSemanticAnalyzeFail;
+            }
+            assert(field_type_val->special != ConstValSpecialRuntime);
+            type_struct_field->type_val = field_type_val;
+            if (struct_type->data.structure.resolve_status == ResolveStatusInvalid)
+                return ErrorSemanticAnalyzeFail;
+        } else if (decl_node->type == NodeTypeContainerInitExpr) {
+            field_type_val = type_struct_field->type_val;
+        } else zig_unreachable();
 
         bool field_is_opaque_type;
         if ((err = type_val_resolve_is_opaque_type(g, field_type_val, &field_is_opaque_type))) {
@@ -2807,7 +2837,7 @@ static Error resolve_struct_alignment(CodeGen *g, ZigType *struct_type) {
     }
 
     struct_type->data.structure.resolve_loop_flag_other = true;
-    assert(decl_node->type == NodeTypeContainerDecl);
+    assert(decl_node->type == NodeTypeContainerDecl || decl_node->type == NodeTypeContainerInitExpr);
 
     size_t field_count = struct_type->data.structure.src_field_count;
     bool packed = struct_type->data.structure.layout == ContainerLayoutPacked;
@@ -2817,7 +2847,8 @@ static Error resolve_struct_alignment(CodeGen *g, ZigType *struct_type) {
         if (field->gen_index == SIZE_MAX)
             continue;
 
-        AstNode *align_expr = field->decl_node->data.struct_field.align_expr;
+        AstNode *align_expr = (field->decl_node->type == NodeTypeStructField) ?
+            field->decl_node->data.struct_field.align_expr : nullptr;
         if (align_expr != nullptr) {
             if (!analyze_const_align(g, &struct_type->data.structure.decls_scope->base, align_expr,
                         &field->align))
@@ -5416,6 +5447,12 @@ OnePossibleValue type_has_one_possible_value(CodeGen *g, ZigType *type_entry) {
     if (type_entry->one_possible_value != OnePossibleValueInvalid)
         return type_entry->one_possible_value;
 
+    if (type_entry->id == ZigTypeIdStruct &&
+        type_entry->data.structure.resolve_status == ResolveStatusBeingInferred)
+    {
+        return OnePossibleValueNo;
+    }
+
     Error err;
     if ((err = type_resolve(g, type_entry, ResolveStatusZeroBitsKnown)))
         return OnePossibleValueInvalid;
@@ -5820,9 +5857,15 @@ ConstExprValue *create_const_arg_tuple(CodeGen *g, size_t arg_index_start, size_
 
 
 ConstExprValue *create_const_vals(size_t count) {
-    ConstGlobalRefs *global_refs = allocate<ConstGlobalRefs>(count, "ConstGlobalRefs");
-    ConstExprValue *vals = allocate<ConstExprValue>(count, "ConstExprValue");
-    for (size_t i = 0; i < count; i += 1) {
+    return realloc_const_vals(nullptr, 0, count);
+}
+
+ConstExprValue *realloc_const_vals(ConstExprValue *base, size_t old_count, size_t new_count) {
+    ConstGlobalRefs *old_global_refs = (base == nullptr) ? nullptr : base->global_refs;
+    ConstGlobalRefs *global_refs = reallocate<ConstGlobalRefs>(old_global_refs, old_count,
+            new_count, "ConstGlobalRefs");
+    ConstExprValue *vals = reallocate<ConstExprValue>(base, old_count, new_count, "ConstExprValue");
+    for (size_t i = old_count; i < new_count; i += 1) {
         vals[i].global_refs = &global_refs[i];
     }
     return vals;
@@ -7002,7 +7045,16 @@ bool type_id_eql(TypeId a, TypeId b) {
                 a.data.pointer.alignment == b.data.pointer.alignment &&
                 a.data.pointer.bit_offset_in_host == b.data.pointer.bit_offset_in_host &&
                 a.data.pointer.vector_index == b.data.pointer.vector_index &&
-                a.data.pointer.host_int_bytes == b.data.pointer.host_int_bytes;
+                a.data.pointer.host_int_bytes == b.data.pointer.host_int_bytes &&
+                (
+                    a.data.pointer.inferred_struct_field == b.data.pointer.inferred_struct_field ||
+                    (a.data.pointer.inferred_struct_field != nullptr &&
+                        b.data.pointer.inferred_struct_field != nullptr &&
+                     a.data.pointer.inferred_struct_field->inferred_struct_type ==
+                        b.data.pointer.inferred_struct_field->inferred_struct_type &&
+                     buf_eql_buf(a.data.pointer.inferred_struct_field->field_name,
+                        b.data.pointer.inferred_struct_field->field_name))
+                );
         case ZigTypeIdArray:
             return a.data.array.child_type == b.data.array.child_type &&
                 a.data.array.size == b.data.array.size;
@@ -7815,7 +7867,6 @@ static void resolve_llvm_types_struct(CodeGen *g, ZigType *struct_type, ResolveS
     ZigLLVMDIScope *di_scope;
     unsigned line;
     if (decl_node != nullptr) {
-        assert(decl_node->type == NodeTypeContainerDecl);
         Scope *scope = &struct_type->data.structure.decls_scope->base;
         ZigType *import = get_scope_import(scope);
         di_file = import->data.structure.root_struct->di_file;
@@ -8018,7 +8069,7 @@ static void resolve_llvm_types_struct(CodeGen *g, ZigType *struct_type, ResolveS
         }
         unsigned line;
         if (decl_node != nullptr) {
-            AstNode *field_node = decl_node->data.container_decl.fields.at(i);
+            AstNode *field_node = field->decl_node;
             line = field_node->line + 1;
         } else {
             line = 0;
@@ -8314,12 +8365,12 @@ static void resolve_llvm_types_pointer(CodeGen *g, ZigType *type, ResolveStatus
         if (type->data.pointer.vector_index == VECTOR_INDEX_NONE) {
             peer_type = get_pointer_to_type_extra2(g, elem_type, false, false,
                 PtrLenSingle, 0, 0, type->data.pointer.host_int_bytes, false,
-                VECTOR_INDEX_NONE);
+                VECTOR_INDEX_NONE, nullptr);
         } else {
             uint32_t host_vec_len = type->data.pointer.host_int_bytes;
             ZigType *host_vec_type = get_vector_type(g, host_vec_len, elem_type);
             peer_type = get_pointer_to_type_extra2(g, host_vec_type, false, false,
-                PtrLenSingle, 0, 0, 0, false, VECTOR_INDEX_NONE);
+                PtrLenSingle, 0, 0, 0, false, VECTOR_INDEX_NONE, nullptr);
         }
         type->llvm_type = get_llvm_type(g, peer_type);
         type->llvm_di_type = get_llvm_di_type(g, peer_type);
src/analyze.hpp
@@ -24,7 +24,7 @@ ZigType *get_pointer_to_type_extra(CodeGen *g, ZigType *child_type,
 ZigType *get_pointer_to_type_extra2(CodeGen *g, ZigType *child_type,
         bool is_const, bool is_volatile, PtrLen ptr_len,
         uint32_t byte_alignment, uint32_t bit_offset, uint32_t unaligned_bit_count,
-        bool allow_zero, uint32_t vector_index);
+        bool allow_zero, uint32_t vector_index, InferredStructField *inferred_struct_field);
 uint64_t type_size(CodeGen *g, ZigType *type_entry);
 uint64_t type_size_bits(CodeGen *g, ZigType *type_entry);
 ZigType *get_int_type(CodeGen *g, bool is_signed, uint32_t size_in_bits);
@@ -175,6 +175,7 @@ void init_const_arg_tuple(CodeGen *g, ConstExprValue *const_val, size_t arg_inde
 ConstExprValue *create_const_arg_tuple(CodeGen *g, size_t arg_index_start, size_t arg_index_end);
 
 ConstExprValue *create_const_vals(size_t count);
+ConstExprValue *realloc_const_vals(ConstExprValue *base, size_t old_count, size_t new_count);
 
 ZigType *make_int_type(CodeGen *g, bool is_signed, uint32_t size_in_bits);
 void expand_undef_array(CodeGen *g, ConstExprValue *const_val);
src/ir.cpp
@@ -202,6 +202,8 @@ static Buf *get_anon_type_name(CodeGen *codegen, IrExecutable *exec, const char
         Scope *scope, AstNode *source_node, Buf *out_bare_name);
 static ResultLocCast *ir_build_cast_result_loc(IrBuilder *irb, IrInstruction *dest_type,
         ResultLoc *parent_result_loc);
+static IrInstruction *ir_analyze_struct_field_ptr(IrAnalyze *ira, IrInstruction *source_instr,
+        TypeStructField *field, IrInstruction *struct_ptr, ZigType *struct_type, bool initializing);
 
 static ConstExprValue *const_ptr_pointee_unchecked(CodeGen *g, ConstExprValue *const_val) {
     assert(get_src_ptr_type(const_val->type) != nullptr);
@@ -16321,13 +16323,81 @@ static IrInstruction *ir_analyze_store_ptr(IrAnalyze *ira, IrInstruction *source
         return ir_const_void(ira, source_instr);
     }
 
-    ZigType *child_type = ptr->value.type->data.pointer.child_type;
+    InferredStructField *isf = ptr->value.type->data.pointer.inferred_struct_field;
+    if (allow_write_through_const && isf != nullptr) {
+        // Now it's time to add the field to the struct type.
+        uint32_t old_field_count = isf->inferred_struct_type->data.structure.src_field_count;
+        uint32_t new_field_count = old_field_count + 1;
+        isf->inferred_struct_type->data.structure.src_field_count = new_field_count;
+        // This thing with max(x, 16) is a hack to allow this functionality to work without
+        // modifying the ConstExprValue layout of structs. That reworking needs to be
+        // done, but this hack lets us do it separately, in the future.
+        TypeStructField *prev_ptr = isf->inferred_struct_type->data.structure.fields;
+        isf->inferred_struct_type->data.structure.fields = reallocate(
+                isf->inferred_struct_type->data.structure.fields,
+                (old_field_count == 0) ? 0 : max(old_field_count, 16u),
+                max(new_field_count, 16u));
+        if (prev_ptr != nullptr && prev_ptr != isf->inferred_struct_type->data.structure.fields) {
+            zig_panic("TODO need to rework the layout of ZigTypeStruct. this realloc would have caused invalid pointer references");
+        }
+
+        // This reference can't live long, don't keep it around outside this block.
+        TypeStructField *field = &isf->inferred_struct_type->data.structure.fields[old_field_count];
+        field->name = isf->field_name;
+        field->type_entry = uncasted_value->value.type;
+        field->type_val = create_const_type(ira->codegen, field->type_entry);
+        field->src_index = old_field_count;
+        field->decl_node = uncasted_value->source_node;
+
+        ZigType *struct_ptr_type = get_pointer_to_type(ira->codegen, isf->inferred_struct_type, false);
+        IrInstruction *casted_ptr;
+        if (instr_is_comptime(ptr)) {
+            casted_ptr = ir_const(ira, source_instr, struct_ptr_type);
+            copy_const_val(&casted_ptr->value, &ptr->value, false);
+            casted_ptr->value.type = struct_ptr_type;
+        } else {
+            casted_ptr = ir_build_cast(&ira->new_irb, source_instr->scope,
+                    source_instr->source_node, struct_ptr_type, ptr, CastOpNoop);
+            casted_ptr->value.type = struct_ptr_type;
+        }
+        if (instr_is_comptime(casted_ptr)) {
+            ConstExprValue *ptr_val = ir_resolve_const(ira, casted_ptr, UndefBad);
+            if (!ptr_val)
+                return ira->codegen->invalid_instruction;
+            if (ptr_val->data.x_ptr.special != ConstPtrSpecialHardCodedAddr) {
+                ConstExprValue *struct_val = const_ptr_pointee(ira, ira->codegen, ptr_val,
+                        source_instr->source_node);
+                struct_val->special = ConstValSpecialStatic;
+                ConstExprValue *prev_ptr = struct_val->data.x_struct.fields;
+                // This thing with max(x, 16) is a hack to allow this functionality to work without
+                // modifying the ConstExprValue layout of structs. That reworking needs to be
+                // done, but this hack lets us do it separately, in the future.
+                struct_val->data.x_struct.fields = realloc_const_vals(struct_val->data.x_struct.fields,
+                        (old_field_count == 0) ? 0 : max(old_field_count, 16u),
+                        max(new_field_count, 16u));
+                if (prev_ptr != nullptr && prev_ptr != struct_val->data.x_struct.fields) {
+                    zig_panic("TODO need to rework the layout of ConstExprValue for structs. this realloc would have caused invalid pointer references");
+                }
+
+                ConstExprValue *field_val = &struct_val->data.x_struct.fields[old_field_count];
+                field_val->special = ConstValSpecialUndef;
+                field_val->type = field->type_entry;
+                field_val->parent.id = ConstParentIdStruct;
+                field_val->parent.data.p_struct.struct_val = struct_val;
+                field_val->parent.data.p_struct.field_index = old_field_count;
+            }
+        }
+
+        ptr = ir_analyze_struct_field_ptr(ira, source_instr, field, casted_ptr,
+                isf->inferred_struct_type, true);
+    }
 
     if (ptr->value.type->data.pointer.is_const && !allow_write_through_const) {
         ir_add_error(ira, source_instr, buf_sprintf("cannot assign to constant"));
         return ira->codegen->invalid_instruction;
     }
 
+    ZigType *child_type = ptr->value.type->data.pointer.child_type;
     IrInstruction *value = ir_implicit_cast(ira, uncasted_value, child_type);
     if (value == ira->codegen->invalid_instruction)
         return ira->codegen->invalid_instruction;
@@ -17853,7 +17923,8 @@ static IrInstruction *ir_analyze_instruction_elem_ptr(IrAnalyze *ira, IrInstruct
             return_type = get_pointer_to_type_extra2(ira->codegen, elem_type,
                 ptr_type->data.pointer.is_const, ptr_type->data.pointer.is_volatile,
                 elem_ptr_instruction->ptr_len,
-                get_ptr_align(ira->codegen, ptr_type), 0, host_vec_len, false, (uint32_t)index);
+                get_ptr_align(ira->codegen, ptr_type), 0, host_vec_len, false, (uint32_t)index,
+                nullptr);
         } else if (return_type->data.pointer.explicit_alignment != 0) {
             // figure out the largest alignment possible
 
@@ -18094,7 +18165,8 @@ static IrInstruction *ir_analyze_instruction_elem_ptr(IrAnalyze *ira, IrInstruct
         return_type = get_pointer_to_type_extra2(ira->codegen, elem_type,
             ptr_type->data.pointer.is_const, ptr_type->data.pointer.is_volatile,
             elem_ptr_instruction->ptr_len,
-            get_ptr_align(ira->codegen, ptr_type), 0, host_vec_len, false, VECTOR_INDEX_RUNTIME);
+            get_ptr_align(ira->codegen, ptr_type), 0, host_vec_len, false, VECTOR_INDEX_RUNTIME,
+            nullptr);
     } else {
         // runtime known element index
         switch (type_requires_comptime(ira->codegen, return_type)) {
@@ -18210,31 +18282,34 @@ static IrInstruction *ir_analyze_struct_field_ptr(IrAnalyze *ira, IrInstruction
         case OnePossibleValueNo:
             break;
     }
-    ResolveStatus needed_resolve_status =
-        (struct_type->data.structure.layout == ContainerLayoutAuto) ?
-            ResolveStatusZeroBitsKnown : ResolveStatusSizeKnown;
-    if ((err = type_resolve(ira->codegen, struct_type, needed_resolve_status)))
-        return ira->codegen->invalid_instruction;
-    assert(struct_ptr->value.type->id == ZigTypeIdPointer);
-    uint32_t ptr_bit_offset = struct_ptr->value.type->data.pointer.bit_offset_in_host;
-    uint32_t ptr_host_int_bytes = struct_ptr->value.type->data.pointer.host_int_bytes;
-    uint32_t host_int_bytes_for_result_type = (ptr_host_int_bytes == 0) ?
-        get_host_int_bytes(ira->codegen, struct_type, field) : ptr_host_int_bytes;
     bool is_const = struct_ptr->value.type->data.pointer.is_const;
     bool is_volatile = struct_ptr->value.type->data.pointer.is_volatile;
-    ZigType *ptr_type = get_pointer_to_type_extra(ira->codegen, field_type,
-            is_const, is_volatile, PtrLenSingle, field->align,
-            (uint32_t)(ptr_bit_offset + field->bit_offset_in_host),
-            (uint32_t)host_int_bytes_for_result_type, false);
+    ZigType *ptr_type;
+    if (struct_type->data.structure.is_inferred) {
+        ptr_type = get_pointer_to_type_extra(ira->codegen, field_type,
+                is_const, is_volatile, PtrLenSingle, 0, 0, 0, false);
+    } else {
+        ResolveStatus needed_resolve_status =
+            (struct_type->data.structure.layout == ContainerLayoutAuto) ?
+                ResolveStatusZeroBitsKnown : ResolveStatusSizeKnown;
+        if ((err = type_resolve(ira->codegen, struct_type, needed_resolve_status)))
+            return ira->codegen->invalid_instruction;
+        assert(struct_ptr->value.type->id == ZigTypeIdPointer);
+        uint32_t ptr_bit_offset = struct_ptr->value.type->data.pointer.bit_offset_in_host;
+        uint32_t ptr_host_int_bytes = struct_ptr->value.type->data.pointer.host_int_bytes;
+        uint32_t host_int_bytes_for_result_type = (ptr_host_int_bytes == 0) ?
+            get_host_int_bytes(ira->codegen, struct_type, field) : ptr_host_int_bytes;
+        ptr_type = get_pointer_to_type_extra(ira->codegen, field_type,
+                is_const, is_volatile, PtrLenSingle, field->align,
+                (uint32_t)(ptr_bit_offset + field->bit_offset_in_host),
+                (uint32_t)host_int_bytes_for_result_type, false);
+    }
     if (instr_is_comptime(struct_ptr)) {
         ConstExprValue *ptr_val = ir_resolve_const(ira, struct_ptr, UndefBad);
         if (!ptr_val)
             return ira->codegen->invalid_instruction;
 
         if (ptr_val->data.x_ptr.special != ConstPtrSpecialHardCodedAddr) {
-            if ((err = type_resolve(ira->codegen, struct_type, ResolveStatusSizeKnown)))
-                return ira->codegen->invalid_instruction;
-
             ConstExprValue *struct_val = const_ptr_pointee(ira, ira->codegen, ptr_val, source_instr->source_node);
             if (struct_val == nullptr)
                 return ira->codegen->invalid_instruction;
@@ -18246,7 +18321,8 @@ static IrInstruction *ir_analyze_struct_field_ptr(IrAnalyze *ira, IrInstruction
                 for (size_t i = 0; i < struct_type->data.structure.src_field_count; i += 1) {
                     ConstExprValue *field_val = &struct_val->data.x_struct.fields[i];
                     field_val->special = ConstValSpecialUndef;
-                    field_val->type = struct_type->data.structure.fields[i].type_entry;
+                    field_val->type = resolve_struct_field_type(ira->codegen,
+                            &struct_type->data.structure.fields[i]);
                     field_val->parent.id = ConstParentIdStruct;
                     field_val->parent.data.p_struct.struct_val = struct_val;
                     field_val->parent.data.p_struct.field_index = i;
@@ -18275,6 +18351,40 @@ static IrInstruction *ir_analyze_struct_field_ptr(IrAnalyze *ira, IrInstruction
     return result;
 }
 
+static IrInstruction *ir_analyze_inferred_field_ptr(IrAnalyze *ira, Buf *field_name,
+    IrInstruction *source_instr, IrInstruction *container_ptr, ZigType *container_type)
+{
+    // The type of the field is not available until a store using this pointer happens.
+    // So, here we create a special pointer type which has the inferred struct type and
+    // field name encoded in the type. Later, when there is a store via this pointer,
+    // the field type will then be available, and the field will be added to the inferred
+    // struct.
+
+    ZigType *container_ptr_type = container_ptr->value.type;
+    ir_assert(container_ptr_type->id == ZigTypeIdPointer, source_instr);
+
+    InferredStructField *inferred_struct_field = allocate<InferredStructField>(1, "InferredStructField");
+    inferred_struct_field->inferred_struct_type = container_type;
+    inferred_struct_field->field_name = field_name;
+
+    ZigType *elem_type = ira->codegen->builtin_types.entry_c_void;
+    ZigType *field_ptr_type = get_pointer_to_type_extra2(ira->codegen, elem_type,
+        container_ptr_type->data.pointer.is_const, container_ptr_type->data.pointer.is_volatile,
+        PtrLenSingle, 0, 0, 0, false, VECTOR_INDEX_NONE, inferred_struct_field);
+
+    if (instr_is_comptime(container_ptr)) {
+        IrInstruction *result = ir_const(ira, source_instr, field_ptr_type);
+        copy_const_val(&result->value, &container_ptr->value, false);
+        result->value.type = field_ptr_type;
+        return result;
+    }
+
+    IrInstruction *result = ir_build_cast(&ira->new_irb, source_instr->scope,
+            source_instr->source_node, field_ptr_type, container_ptr, CastOpNoop);
+    result->value.type = field_ptr_type;
+    return result;
+}
+
 static IrInstruction *ir_analyze_container_field_ptr(IrAnalyze *ira, Buf *field_name,
     IrInstruction *source_instr, IrInstruction *container_ptr, ZigType *container_type, bool initializing)
 {
@@ -18282,6 +18392,12 @@ static IrInstruction *ir_analyze_container_field_ptr(IrAnalyze *ira, Buf *field_
 
     ZigType *bare_type = container_ref_type(container_type);
 
+    if (initializing && bare_type->id == ZigTypeIdStruct &&
+        bare_type->data.structure.resolve_status == ResolveStatusBeingInferred)
+    {
+        return ir_analyze_inferred_field_ptr(ira, field_name, source_instr, container_ptr, bare_type);
+    }
+
     if ((err = type_resolve(ira->codegen, bare_type, ResolveStatusZeroBitsKnown)))
         return ira->codegen->invalid_instruction;
 
@@ -20056,6 +20172,11 @@ static IrInstruction *ir_analyze_container_init_fields(IrAnalyze *ira, IrInstruc
         return ira->codegen->invalid_instruction;
     }
 
+    if (container_type->data.structure.resolve_status == ResolveStatusBeingInferred) {
+        // We're now done inferring the type.
+        container_type->data.structure.resolve_status = ResolveStatusUnstarted;
+    }
+
     if ((err = type_resolve(ira->codegen, container_type, ResolveStatusSizeKnown)))
         return ira->codegen->invalid_instruction;
 
test/stage1/behavior/struct.zig
@@ -729,3 +729,25 @@ test "anonymous struct literal syntax" {
     S.doTheTest();
     comptime S.doTheTest();
 }
+
+test "fully anonymous struct" {
+    const S = struct {
+        fn doTheTest() void {
+            dump(.{
+                .int = @as(u32, 1234),
+                .float = @as(f64, 12.34),
+                .b = true,
+                .s = "hi",
+            });
+        }
+        fn dump(args: var) void {
+            expect(args.int == 1234);
+            expect(args.float == 12.34);
+            expect(args.b);
+            expect(args.s[0] == 'h');
+            expect(args.s[1] == 'i');
+        }
+    };
+    S.doTheTest();
+    comptime S.doTheTest();
+}