implement anon struct literal syntax

This implements stage1 parser support for anonymous struct literal
syntax (see #685), as well as semantic analysis support for anonymous
struct literals and anonymous list literals (see #208). The semantic
analysis works when there is a type coercion in the result location;
inferring the struct type based on the values in the literal is not
implemented yet. Also remaining to do is zig fmt support for this new
syntax and documentation updates.

lib/std/builtin.zig

@@ -90,40 +90,11 @@ pub const Mode = enum {
     ReleaseSmall,
 };
 
-/// This data structure is used by the Zig language code generation and
-/// therefore must be kept in sync with the compiler implementation.
-pub const TypeId = enum {
-    Type,
-    Void,
-    Bool,
-    NoReturn,
-    Int,
-    Float,
-    Pointer,
-    Array,
-    Struct,
-    ComptimeFloat,
-    ComptimeInt,
-    Undefined,
-    Null,
-    Optional,
-    ErrorUnion,
-    ErrorSet,
-    Enum,
-    Union,
-    Fn,
-    BoundFn,
-    ArgTuple,
-    Opaque,
-    Frame,
-    AnyFrame,
-    Vector,
-    EnumLiteral,
-};
+pub const TypeId = @TagType(TypeInfo);
 
 /// This data structure is used by the Zig language code generation and
 /// therefore must be kept in sync with the compiler implementation.
-pub const TypeInfo = union(TypeId) {
+pub const TypeInfo = union(enum) {
     Type: void,
     Void: void,
     Bool: void,

src/all_types.hpp

@@ -1237,6 +1237,7 @@ struct TypeStructField {
 enum ResolveStatus {
     ResolveStatusUnstarted,
     ResolveStatusInvalid,
+    ResolveStatusBeingInferred,
     ResolveStatusZeroBitsKnown,
     ResolveStatusAlignmentKnown,
     ResolveStatusSizeKnown,
@@ -1285,6 +1286,7 @@ struct ZigTypeStruct {
     bool requires_comptime;
     bool resolve_loop_flag_zero_bits;
     bool resolve_loop_flag_other;
+    bool is_inferred;
 };
 
 struct ZigTypeOptional {
@@ -2812,7 +2814,7 @@ struct IrInstructionElemPtr {
 
     IrInstruction *array_ptr;
     IrInstruction *elem_index;
-    IrInstruction *init_array_type;
+    AstNode *init_array_type_source_node;
     PtrLen ptr_len;
     bool safety_check_on;
 };
@@ -2909,11 +2911,11 @@ struct IrInstructionResizeSlice {
 struct IrInstructionContainerInitList {
     IrInstruction base;
 
-    IrInstruction *container_type;
     IrInstruction *elem_type;
     size_t item_count;
     IrInstruction **elem_result_loc_list;
     IrInstruction *result_loc;
+    AstNode *init_array_type_source_node;
 };
 
 struct IrInstructionContainerInitFieldsField {
@@ -2926,7 +2928,6 @@ struct IrInstructionContainerInitFieldsField {
 struct IrInstructionContainerInitFields {
     IrInstruction base;
 
-    IrInstruction *container_type;
     size_t field_count;
     IrInstructionContainerInitFieldsField *fields;
     IrInstruction *result_loc;

src/analyze.cpp

@@ -140,7 +140,6 @@ void init_scope(CodeGen *g, Scope *dest, ScopeId id, AstNode *source_node, Scope
 static ScopeDecls *create_decls_scope(CodeGen *g, AstNode *node, Scope *parent, ZigType *container_type,
         ZigType *import, Buf *bare_name)
 {
-    assert(node == nullptr || node->type == NodeTypeContainerDecl || node->type == NodeTypeFnCallExpr);
     ScopeDecls *scope = allocate<ScopeDecls>(1);
     init_scope(g, &scope->base, ScopeIdDecls, node, parent);
     scope->decl_table.init(4);
@@ -346,6 +345,8 @@ bool type_is_resolved(ZigType *type_entry, ResolveStatus status) {
             switch (status) {
                 case ResolveStatusInvalid:
                     zig_unreachable();
+                case ResolveStatusBeingInferred:
+                    zig_unreachable();
                 case ResolveStatusUnstarted:
                 case ResolveStatusZeroBitsKnown:
                     return true;
@@ -362,6 +363,8 @@ bool type_is_resolved(ZigType *type_entry, ResolveStatus status) {
             switch (status) {
                 case ResolveStatusInvalid:
                     zig_unreachable();
+                case ResolveStatusBeingInferred:
+                    zig_unreachable();
                 case ResolveStatusUnstarted:
                     return true;
                 case ResolveStatusZeroBitsKnown:
@@ -6132,6 +6135,8 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
                 continue;
             if (instruction->ref_count == 0)
                 continue;
+            if ((err = type_resolve(g, instruction->value.type, ResolveStatusZeroBitsKnown)))
+                return ErrorSemanticAnalyzeFail;
             if (!type_has_bits(instruction->value.type))
                 continue;
             if (scope_needs_spill(instruction->scope)) {
@@ -6271,6 +6276,8 @@ Error type_resolve(CodeGen *g, ZigType *ty, ResolveStatus status) {
     switch (status) {
         case ResolveStatusUnstarted:
             return ErrorNone;
+        case ResolveStatusBeingInferred:
+            zig_unreachable();
         case ResolveStatusInvalid:
             zig_unreachable();
         case ResolveStatusZeroBitsKnown:
@@ -9038,4 +9045,3 @@ Error analyze_import(CodeGen *g, ZigType *source_import, Buf *import_target_str,
     *out_import = add_source_file(g, target_package, resolved_path, import_code, source_kind);
     return ErrorNone;
 }
-

src/ast_render.cpp

@@ -821,7 +821,9 @@ static void render_node_extra(AstRender *ar, AstNode *node, bool grouped) {
                 break;
             }
         case NodeTypeContainerInitExpr:
-            render_node_ungrouped(ar, node->data.container_init_expr.type);
+            if (node->data.container_init_expr.type != nullptr) {
+                render_node_ungrouped(ar, node->data.container_init_expr.type);
+            }
             if (node->data.container_init_expr.kind == ContainerInitKindStruct) {
                 fprintf(ar->f, "{\n");
                 ar->indent += ar->indent_size;