var is no longer a pseudo-type, it is syntax

closes #779

doc/langref.html.in

@@ -5733,19 +5733,19 @@ UseDecl = "use" Expression ";"
 
 ExternDecl = "extern" option(String) (FnProto | VariableDeclaration) ";"
 
-FnProto = option("nakedcc" | "stdcallcc" | "extern" | ("async" option("(" Expression ")"))) "fn" option(Symbol) ParamDeclList option("align" "(" Expression ")") option("section" "(" Expression ")") option("!") TypeExpr
+FnProto = option("nakedcc" | "stdcallcc" | "extern" | ("async" option("(" Expression ")"))) "fn" option(Symbol) ParamDeclList option("align" "(" Expression ")") option("section" "(" Expression ")") option("!") (TypeExpr | "var")
 
 FnDef = option("inline" | "export") FnProto Block
 
 ParamDeclList = "(" list(ParamDecl, ",") ")"
 
-ParamDecl = option("noalias" | "comptime") option(Symbol ":") (TypeExpr | "...")
+ParamDecl = option("noalias" | "comptime") option(Symbol ":") (TypeExpr | "var" | "...")
 
 Block = option(Symbol ":") "{" many(Statement) "}"
 
 Statement = LocalVarDecl ";" | Defer(Block) | Defer(Expression) ";" | BlockExpression(Block) | Expression ";" | ";"
 
-TypeExpr = ErrorSetExpr | "var"
+TypeExpr = ErrorSetExpr
 
 ErrorSetExpr = (PrefixOpExpression "!" PrefixOpExpression) | PrefixOpExpression
 

src/all_types.hpp

@@ -16,6 +16,7 @@
 #include "bigint.hpp"
 #include "bigfloat.hpp"
 #include "target.hpp"
+#include "tokenizer.hpp"
 
 struct AstNode;
 struct ImportTableEntry;
@@ -399,7 +400,6 @@ enum NodeType {
     NodeTypeStructValueField,
     NodeTypeArrayType,
     NodeTypeErrorType,
-    NodeTypeVarLiteral,
     NodeTypeIfErrorExpr,
     NodeTypeTestExpr,
     NodeTypeErrorSetDecl,
@@ -427,6 +427,7 @@ struct AstNodeFnProto {
     Buf *name;
     ZigList<AstNode *> params;
     AstNode *return_type;
+    Token *return_var_token;
     bool is_var_args;
     bool is_extern;
     bool is_export;
@@ -456,6 +457,7 @@ struct AstNodeFnDecl {
 struct AstNodeParamDecl {
     Buf *name;
     AstNode *type;
+    Token *var_token;
     bool is_noalias;
     bool is_inline;
     bool is_var_args;
@@ -866,9 +868,6 @@ struct AstNodeUnreachableExpr {
 struct AstNodeErrorType {
 };
 
-struct AstNodeVarLiteral {
-};
-
 struct AstNodeAwaitExpr {
     AstNode *expr;
 };
@@ -933,7 +932,6 @@ struct AstNode {
         AstNodeUnreachableExpr unreachable_expr;
         AstNodeArrayType array_type;
         AstNodeErrorType error_type;
-        AstNodeVarLiteral var_literal;
         AstNodeErrorSetDecl err_set_decl;
         AstNodeCancelExpr cancel_expr;
         AstNodeResumeExpr resume_expr;
@@ -1134,7 +1132,6 @@ struct TypeTableEntryPromise {
 
 enum TypeTableEntryId {
     TypeTableEntryIdInvalid,
-    TypeTableEntryIdVar,
     TypeTableEntryIdMetaType,
     TypeTableEntryIdVoid,
     TypeTableEntryIdBool,

src/analyze.cpp

@@ -200,7 +200,6 @@ static uint8_t bits_needed_for_unsigned(uint64_t x) {
 bool type_is_complete(TypeTableEntry *type_entry) {
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdStruct:
             return type_entry->data.structure.complete;
@@ -239,7 +238,6 @@ bool type_is_complete(TypeTableEntry *type_entry) {
 bool type_has_zero_bits_known(TypeTableEntry *type_entry) {
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdStruct:
             return type_entry->data.structure.zero_bits_known;
@@ -1281,7 +1279,6 @@ static bool analyze_const_string(CodeGen *g, Scope *scope, AstNode *node, Buf **
 static bool type_allowed_in_packed_struct(TypeTableEntry *type_entry) {
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdUnreachable:
@@ -1324,7 +1321,6 @@ static bool type_allowed_in_packed_struct(TypeTableEntry *type_entry) {
 static bool type_allowed_in_extern(CodeGen *g, TypeTableEntry *type_entry) {
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdNumLitFloat:
@@ -1428,6 +1424,14 @@ static TypeTableEntry *analyze_fn_type(CodeGen *g, AstNode *proto_node, Scope *c
                             calling_convention_name(fn_type_id.cc)));
                 return g->builtin_types.entry_invalid;
             }
+        } else if (param_node->data.param_decl.var_token != nullptr) {
+            if (!calling_convention_allows_zig_types(fn_type_id.cc)) {
+                add_node_error(g, param_node->data.param_decl.type,
+                        buf_sprintf("parameter of type 'var' not allowed in function with calling convention '%s'",
+                            calling_convention_name(fn_type_id.cc)));
+                return g->builtin_types.entry_invalid;
+            }
+            return get_generic_fn_type(g, &fn_type_id);
         }
 
         TypeTableEntry *type_entry = analyze_type_expr(g, child_scope, param_node->data.param_decl.type);
@@ -1463,14 +1467,6 @@ static TypeTableEntry *analyze_fn_type(CodeGen *g, AstNode *proto_node, Scope *c
                 add_node_error(g, param_node->data.param_decl.type,
                     buf_sprintf("parameter of type '%s' not allowed", buf_ptr(&type_entry->name)));
                 return g->builtin_types.entry_invalid;
-            case TypeTableEntryIdVar:
-                if (!calling_convention_allows_zig_types(fn_type_id.cc)) {
-                    add_node_error(g, param_node->data.param_decl.type,
-                            buf_sprintf("parameter of type 'var' not allowed in function with calling convention '%s'",
-                                calling_convention_name(fn_type_id.cc)));
-                    return g->builtin_types.entry_invalid;
-                }
-                return get_generic_fn_type(g, &fn_type_id);
             case TypeTableEntryIdNumLitFloat:
             case TypeTableEntryIdNumLitInt:
             case TypeTableEntryIdNamespace:
@@ -1527,6 +1523,16 @@ static TypeTableEntry *analyze_fn_type(CodeGen *g, AstNode *proto_node, Scope *c
         fn_type_id.return_type = specified_return_type;
     }
 
+    if (fn_proto->return_var_token != nullptr) {
+        if (!calling_convention_allows_zig_types(fn_type_id.cc)) {
+            add_node_error(g, fn_proto->return_type,
+                buf_sprintf("return type 'var' not allowed in function with calling convention '%s'",
+                calling_convention_name(fn_type_id.cc)));
+            return g->builtin_types.entry_invalid;
+        }
+        return get_generic_fn_type(g, &fn_type_id);
+    }
+
     if (!calling_convention_allows_zig_types(fn_type_id.cc) && !type_allowed_in_extern(g, fn_type_id.return_type)) {
         add_node_error(g, fn_proto->return_type,
                 buf_sprintf("return type '%s' not allowed in function with calling convention '%s'",
@@ -1552,7 +1558,6 @@ static TypeTableEntry *analyze_fn_type(CodeGen *g, AstNode *proto_node, Scope *c
         case TypeTableEntryIdNamespace:
         case TypeTableEntryIdBlock:
         case TypeTableEntryIdBoundFn:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
             if (!calling_convention_allows_zig_types(fn_type_id.cc)) {
                 add_node_error(g, fn_proto->return_type,
@@ -3226,7 +3231,6 @@ void scan_decls(CodeGen *g, ScopeDecls *decls_scope, AstNode *node) {
         case NodeTypeStructValueField:
         case NodeTypeArrayType:
         case NodeTypeErrorType:
-        case NodeTypeVarLiteral:
         case NodeTypeIfErrorExpr:
         case NodeTypeTestExpr:
         case NodeTypeErrorSetDecl:
@@ -3262,7 +3266,6 @@ TypeTableEntry *validate_var_type(CodeGen *g, AstNode *source_node, TypeTableEnt
         case TypeTableEntryIdInvalid:
             return g->builtin_types.entry_invalid;
         case TypeTableEntryIdUnreachable:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdNumLitFloat:
         case TypeTableEntryIdNumLitInt:
         case TypeTableEntryIdUndefLit:
@@ -3641,7 +3644,6 @@ TypeEnumField *find_enum_field_by_tag(TypeTableEntry *enum_type, const BigInt *t
 static bool is_container(TypeTableEntry *type_entry) {
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdStruct:
         case TypeTableEntryIdEnum:
@@ -3716,7 +3718,6 @@ void resolve_container_type(CodeGen *g, TypeTableEntry *type_entry) {
         case TypeTableEntryIdBlock:
         case TypeTableEntryIdBoundFn:
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdArgTuple:
         case TypeTableEntryIdOpaque:
         case TypeTableEntryIdPromise:
@@ -4216,7 +4217,6 @@ bool handle_is_ptr(TypeTableEntry *type_entry) {
         case TypeTableEntryIdNamespace:
         case TypeTableEntryIdBlock:
         case TypeTableEntryIdBoundFn:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdArgTuple:
         case TypeTableEntryIdOpaque:
              zig_unreachable();
@@ -4515,7 +4515,6 @@ static uint32_t hash_const_val(ConstExprValue *const_val) {
         case TypeTableEntryIdBoundFn:
         case TypeTableEntryIdInvalid:
         case TypeTableEntryIdUnreachable:
-        case TypeTableEntryIdVar:
             zig_unreachable();
     }
     zig_unreachable();
@@ -4613,7 +4612,6 @@ bool type_has_bits(TypeTableEntry *type_entry) {
 bool type_requires_comptime(TypeTableEntry *type_entry) {
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdOpaque:
             zig_unreachable();
         case TypeTableEntryIdNumLitFloat:
@@ -5109,7 +5107,6 @@ bool const_values_equal(ConstExprValue *a, ConstExprValue *b) {
         case TypeTableEntryIdBoundFn:
         case TypeTableEntryIdInvalid:
         case TypeTableEntryIdUnreachable:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdPromise:
             zig_unreachable();
     }
@@ -5189,9 +5186,6 @@ void render_const_value(CodeGen *g, Buf *buf, ConstExprValue *const_val) {
         case TypeTableEntryIdInvalid:
             buf_appendf(buf, "(invalid)");
             return;
-        case TypeTableEntryIdVar:
-            buf_appendf(buf, "(var)");
-            return;
         case TypeTableEntryIdVoid:
             buf_appendf(buf, "{}");
             return;
@@ -5427,7 +5421,6 @@ TypeTableEntry *make_int_type(CodeGen *g, bool is_signed, uint32_t size_in_bits)
 uint32_t type_id_hash(TypeId x) {
     switch (x.id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdOpaque:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdVoid:
@@ -5474,7 +5467,6 @@ bool type_id_eql(TypeId a, TypeId b) {
         return false;
     switch (a.id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdVoid:
         case TypeTableEntryIdBool:
@@ -5629,7 +5621,6 @@ size_t type_id_len() {
 size_t type_id_index(TypeTableEntryId id) {
     switch (id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdMetaType:
             return 0;
@@ -5688,7 +5679,6 @@ size_t type_id_index(TypeTableEntryId id) {
 const char *type_id_name(TypeTableEntryId id) {
     switch (id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdMetaType:
             return "Type";

src/ast_render.cpp

@@ -236,8 +236,6 @@ static const char *node_type_str(NodeType node_type) {
             return "ArrayType";
         case NodeTypeErrorType:
             return "ErrorType";
-        case NodeTypeVarLiteral:
-            return "VarLiteral";
         case NodeTypeIfErrorExpr:
             return "IfErrorExpr";
         case NodeTypeTestExpr:
@@ -436,6 +434,8 @@ static void render_node_extra(AstRender *ar, AstNode *node, bool grouped) {
                     }
                     if (param_decl->data.param_decl.is_var_args) {
                         fprintf(ar->f, "...");
+                    } else if (param_decl->data.param_decl.var_token != nullptr) {
+                        fprintf(ar->f, "var");
                     } else {
                         render_node_grouped(ar, param_decl->data.param_decl.type);
                     }
@@ -456,13 +456,17 @@ static void render_node_extra(AstRender *ar, AstNode *node, bool grouped) {
                     fprintf(ar->f, ")");
                 }
 
-                AstNode *return_type_node = node->data.fn_proto.return_type;
+                if (node->data.fn_proto.return_var_token != nullptr) {
-                assert(return_type_node != nullptr);
+                    fprintf(ar->f, "var");
-                fprintf(ar->f, " ");
+                } else {
-                if (node->data.fn_proto.auto_err_set) {
+                    AstNode *return_type_node = node->data.fn_proto.return_type;
-                    fprintf(ar->f, "!");
+                    assert(return_type_node != nullptr);
+                    fprintf(ar->f, " ");
+                    if (node->data.fn_proto.auto_err_set) {
+                        fprintf(ar->f, "!");
+                    }
+                    render_node_grouped(ar, return_type_node);
                 }
-                render_node_grouped(ar, return_type_node);
                 break;
             }
         case NodeTypeFnDef:
@@ -768,9 +772,6 @@ static void render_node_extra(AstRender *ar, AstNode *node, bool grouped) {
         case NodeTypeErrorType:
             fprintf(ar->f, "error");
             break;
-        case NodeTypeVarLiteral:
-            fprintf(ar->f, "var");
-            break;
         case NodeTypeAsmExpr:
             {
                 AstNodeAsmExpr *asm_expr = &node->data.asm_expr;

src/codegen.cpp

@@ -4508,7 +4508,6 @@ static LLVMValueRef pack_const_int(CodeGen *g, LLVMTypeRef big_int_type_ref, Con
     assert(!type_entry->zero_bits);
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdUnreachable:
         case TypeTableEntryIdNumLitFloat:
@@ -4960,7 +4959,6 @@ static LLVMValueRef gen_const_val(CodeGen *g, ConstExprValue *const_val, const c
         case TypeTableEntryIdNamespace:
         case TypeTableEntryIdBlock:
         case TypeTableEntryIdBoundFn:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdArgTuple:
         case TypeTableEntryIdOpaque:
         case TypeTableEntryIdPromise:
@@ -5611,11 +5609,6 @@ static void define_builtin_types(CodeGen *g) {
         entry->zero_bits = true;
         g->builtin_types.entry_null = entry;
     }
-    {
-        TypeTableEntry *entry = new_type_table_entry(TypeTableEntryIdVar);
-        buf_init_from_str(&entry->name, "(var)");
-        g->builtin_types.entry_var = entry;
-    }
     {
         TypeTableEntry *entry = new_type_table_entry(TypeTableEntryIdArgTuple);
         buf_init_from_str(&entry->name, "(args)");
@@ -6444,7 +6437,6 @@ static void prepend_c_type_to_decl_list(CodeGen *g, GenH *gen_h, TypeTableEntry
 
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdNumLitFloat:
         case TypeTableEntryIdNumLitInt:
@@ -6639,7 +6631,6 @@ static void get_c_type(CodeGen *g, GenH *gen_h, TypeTableEntry *type_entry, Buf
         case TypeTableEntryIdNumLitInt:
         case TypeTableEntryIdUndefLit:
         case TypeTableEntryIdNullLit:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdArgTuple:
         case TypeTableEntryIdPromise:
             zig_unreachable();
@@ -6781,7 +6772,6 @@ static void gen_h_file(CodeGen *g) {
         TypeTableEntry *type_entry = gen_h->types_to_declare.at(type_i);
         switch (type_entry->id) {
             case TypeTableEntryIdInvalid:
-            case TypeTableEntryIdVar:
             case TypeTableEntryIdMetaType:
             case TypeTableEntryIdVoid:
             case TypeTableEntryIdBool:

src/ir.cpp

@@ -2147,7 +2147,7 @@ static IrInstruction *ir_build_fn_proto(IrBuilder *irb, Scope *scope, AstNode *s
     size_t param_count = source_node->data.fn_proto.params.length;
     if (is_var_args) param_count -= 1;
     for (size_t i = 0; i < param_count; i += 1) {
-        ir_ref_instruction(param_types[i], irb->current_basic_block);
+        if (param_types[i] != nullptr) ir_ref_instruction(param_types[i], irb->current_basic_block);
     }
     if (align_value != nullptr) ir_ref_instruction(align_value, irb->current_basic_block);
     ir_ref_instruction(return_type, irb->current_basic_block);
@@ -3305,12 +3305,6 @@ static IrInstruction *ir_gen_null_literal(IrBuilder *irb, Scope *scope, AstNode
     return ir_build_const_null(irb, scope, node);
 }
 
-static IrInstruction *ir_gen_var_literal(IrBuilder *irb, Scope *scope, AstNode *node) {
-    assert(node->type == NodeTypeVarLiteral);
-
-    return ir_build_const_type(irb, scope, node, irb->codegen->builtin_types.entry_var);
-}
-
 static IrInstruction *ir_gen_symbol(IrBuilder *irb, Scope *scope, AstNode *node, LVal lval) {
     assert(node->type == NodeTypeSymbol);
 
@@ -5916,11 +5910,15 @@ static IrInstruction *ir_gen_fn_proto(IrBuilder *irb, Scope *parent_scope, AstNo
             is_var_args = true;
             break;
         }
-        AstNode *type_node = param_node->data.param_decl.type;
+        if (param_node->data.param_decl.var_token == nullptr) {
-        IrInstruction *type_value = ir_gen_node(irb, type_node, parent_scope);
+            AstNode *type_node = param_node->data.param_decl.type;
-        if (type_value == irb->codegen->invalid_instruction)
+            IrInstruction *type_value = ir_gen_node(irb, type_node, parent_scope);
-            return irb->codegen->invalid_instruction;
+            if (type_value == irb->codegen->invalid_instruction)
-        param_types[i] = type_value;
+                return irb->codegen->invalid_instruction;
+            param_types[i] = type_value;
+        } else {
+            param_types[i] = nullptr;
+        }
     }
 
     IrInstruction *align_value = nullptr;
@@ -5931,12 +5929,16 @@ static IrInstruction *ir_gen_fn_proto(IrBuilder *irb, Scope *parent_scope, AstNo
     }
 
     IrInstruction *return_type;
-    if (node->data.fn_proto.return_type == nullptr) {
+    if (node->data.fn_proto.return_var_token == nullptr) {
-        return_type = ir_build_const_type(irb, parent_scope, node, irb->codegen->builtin_types.entry_void);
+        if (node->data.fn_proto.return_type == nullptr) {
+            return_type = ir_build_const_type(irb, parent_scope, node, irb->codegen->builtin_types.entry_void);
+        } else {
+            return_type = ir_gen_node(irb, node->data.fn_proto.return_type, parent_scope);
+            if (return_type == irb->codegen->invalid_instruction)
+                return irb->codegen->invalid_instruction;
+        }
     } else {
-        return_type = ir_gen_node(irb, node->data.fn_proto.return_type, parent_scope);
+        return_type = nullptr;
-        if (return_type == irb->codegen->invalid_instruction)
-            return irb->codegen->invalid_instruction;
     }
 
     return ir_build_fn_proto(irb, parent_scope, node, param_types, align_value, return_type, is_var_args);
@@ -6189,8 +6191,6 @@ static IrInstruction *ir_gen_node_raw(IrBuilder *irb, AstNode *node, Scope *scop
             return ir_lval_wrap(irb, scope, ir_gen_asm_expr(irb, scope, node), lval);
         case NodeTypeNullLiteral:
             return ir_lval_wrap(irb, scope, ir_gen_null_literal(irb, scope, node), lval);
-        case NodeTypeVarLiteral:
-            return ir_lval_wrap(irb, scope, ir_gen_var_literal(irb, scope, node), lval);
         case NodeTypeIfErrorExpr:
             return ir_lval_wrap(irb, scope, ir_gen_if_err_expr(irb, scope, node), lval);
         case NodeTypeTestExpr:
@@ -7515,11 +7515,6 @@ static ImplicitCastMatchResult ir_types_match_with_implicit_cast(IrAnalyze *ira,
         return ImplicitCastMatchResultReportedError;
     }
 
-    // implicit conversion from anything to var
-    if (expected_type->id == TypeTableEntryIdVar) {
-        return ImplicitCastMatchResultYes;
-    }
-
     // implicit conversion from non maybe type to maybe type
     if (expected_type->id == TypeTableEntryIdMaybe &&
         ir_types_match_with_implicit_cast(ira, expected_type->data.maybe.child_type, actual_type, value))
@@ -9341,9 +9336,6 @@ static IrInstruction *ir_analyze_cast(IrAnalyze *ira, IrInstruction *source_inst
         return ira->codegen->invalid_instruction;
     }
 
-    if (wanted_type->id == TypeTableEntryIdVar)
-        return value;
-
     // explicit match or non-const to const
     if (types_match_const_cast_only(ira, wanted_type, actual_type, source_node).id == ConstCastResultIdOk) {
         return ir_resolve_cast(ira, source_instr, value, wanted_type, CastOpNoop, false);
@@ -10311,9 +10303,6 @@ static TypeTableEntry *ir_analyze_bin_op_cmp(IrAnalyze *ira, IrInstructionBinOp
             ir_add_error_node(ira, source_node,
                 buf_sprintf("operator not allowed for type '%s'", buf_ptr(&resolved_type->name)));
             return ira->codegen->builtin_types.entry_invalid;
-
-        case TypeTableEntryIdVar:
-            zig_unreachable();
     }
 
     IrInstruction *casted_op1 = ir_implicit_cast(ira, op1, resolved_type);
@@ -11106,7 +11095,6 @@ static VarClassRequired get_var_class_required(TypeTableEntry *type_entry) {
         case TypeTableEntryIdInvalid:
             zig_unreachable();
         case TypeTableEntryIdUnreachable:
-        case TypeTableEntryIdVar:
             return VarClassRequiredIllegal;
         case TypeTableEntryIdBool:
         case TypeTableEntryIdInt:
@@ -11279,7 +11267,6 @@ static TypeTableEntry *ir_analyze_instruction_export(IrAnalyze *ira, IrInstructi
 
     switch (target->value.type->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdUnreachable:
             zig_unreachable();
         case TypeTableEntryIdFn: {
@@ -11332,7 +11319,6 @@ static TypeTableEntry *ir_analyze_instruction_export(IrAnalyze *ira, IrInstructi
             TypeTableEntry *type_value = target->value.data.x_type;
             switch (type_value->id) {
                 case TypeTableEntryIdInvalid:
-                case TypeTableEntryIdVar:
                     zig_unreachable();
                 case TypeTableEntryIdStruct:
                     if (is_slice(type_value)) {
@@ -11543,14 +11529,20 @@ static bool ir_analyze_fn_call_inline_arg(IrAnalyze *ira, AstNode *fn_proto_node
 {
     AstNode *param_decl_node = fn_proto_node->data.fn_proto.params.at(*next_proto_i);
     assert(param_decl_node->type == NodeTypeParamDecl);
-    AstNode *param_type_node = param_decl_node->data.param_decl.type;
-    TypeTableEntry *param_type = analyze_type_expr(ira->codegen, *exec_scope, param_type_node);
-    if (type_is_invalid(param_type))
-        return false;
 
-    IrInstruction *casted_arg = ir_implicit_cast(ira, arg, param_type);
+    IrInstruction *casted_arg;
-    if (type_is_invalid(casted_arg->value.type))
+    if (param_decl_node->data.param_decl.var_token == nullptr) {
-        return false;
+        AstNode *param_type_node = param_decl_node->data.param_decl.type;
+        TypeTableEntry *param_type = analyze_type_expr(ira->codegen, *exec_scope, param_type_node);
+        if (type_is_invalid(param_type))
+            return false;
+
+        casted_arg = ir_implicit_cast(ira, arg, param_type);
+        if (type_is_invalid(casted_arg->value.type))
+            return false;
+    } else {
+        casted_arg = arg;
+    }
 
     ConstExprValue *arg_val = ir_resolve_const(ira, casted_arg, UndefBad);
     if (!arg_val)
@@ -11579,19 +11571,18 @@ static bool ir_analyze_fn_call_generic_arg(IrAnalyze *ira, AstNode *fn_proto_nod
         arg_part_of_generic_id = true;
         casted_arg = ir_implicit_byval_const_ref_cast(ira, arg);
     } else {
-        AstNode *param_type_node = param_decl_node->data.param_decl.type;
+        if (param_decl_node->data.param_decl.var_token == nullptr) {
-        TypeTableEntry *param_type = analyze_type_expr(ira->codegen, *child_scope, param_type_node);
+            AstNode *param_type_node = param_decl_node->data.param_decl.type;
-        if (type_is_invalid(param_type))
+            TypeTableEntry *param_type = analyze_type_expr(ira->codegen, *child_scope, param_type_node);
-            return false;
+            if (type_is_invalid(param_type))
+                return false;
 
-        bool is_var_type = (param_type->id == TypeTableEntryIdVar);
-        if (is_var_type) {
-            arg_part_of_generic_id = true;
-            casted_arg = ir_implicit_byval_const_ref_cast(ira, arg);
-        } else {
             casted_arg = ir_implicit_cast(ira, arg, param_type);
             if (type_is_invalid(casted_arg->value.type))
                 return false;
+        } else {
+            arg_part_of_generic_id = true;
+            casted_arg = ir_implicit_byval_const_ref_cast(ira, arg);
         }
     }
 
@@ -12304,7 +12295,6 @@ static TypeTableEntry *ir_analyze_maybe(IrAnalyze *ira, IrInstructionUnOp *un_op
         return ira->codegen->builtin_types.entry_invalid;
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdVoid:
@@ -13539,10 +13529,6 @@ static TypeTableEntry *ir_analyze_instruction_typeof(IrAnalyze *ira, IrInstructi
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
             zig_unreachable(); // handled above
-        case TypeTableEntryIdVar:
-            ir_add_error_node(ira, expr_value->source_node,
-                    buf_sprintf("type '%s' not eligible for @typeOf", buf_ptr(&type_entry->name)));
-            return ira->codegen->builtin_types.entry_invalid;
         case TypeTableEntryIdNumLitFloat:
         case TypeTableEntryIdNumLitInt:
         case TypeTableEntryIdUndefLit:
@@ -13807,7 +13793,6 @@ static TypeTableEntry *ir_analyze_instruction_slice_type(IrAnalyze *ira,
     switch (child_type->id) {
         case TypeTableEntryIdInvalid: // handled above
             zig_unreachable();
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdUnreachable:
         case TypeTableEntryIdUndefLit:
         case TypeTableEntryIdNullLit:
@@ -13916,7 +13901,6 @@ static TypeTableEntry *ir_analyze_instruction_array_type(IrAnalyze *ira,
     switch (child_type->id) {
         case TypeTableEntryIdInvalid: // handled above
             zig_unreachable();
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdUnreachable:
         case TypeTableEntryIdUndefLit:
         case TypeTableEntryIdNullLit:
@@ -13968,7 +13952,6 @@ static TypeTableEntry *ir_analyze_instruction_size_of(IrAnalyze *ira,
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid: // handled above
             zig_unreachable();
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdUnreachable:
         case TypeTableEntryIdUndefLit:
         case TypeTableEntryIdNullLit:
@@ -14316,7 +14299,6 @@ static TypeTableEntry *ir_analyze_instruction_switch_target(IrAnalyze *ira,
 
     switch (target_type->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdVoid:
@@ -14911,7 +14893,6 @@ static TypeTableEntry *ir_analyze_min_max(IrAnalyze *ira, IrInstruction *source_
             }
         case TypeTableEntryIdEnum:
             zig_panic("TODO min/max value for enum type");
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdUnreachable:
         case TypeTableEntryIdPointer:
@@ -16159,7 +16140,6 @@ static TypeTableEntry *ir_analyze_instruction_align_of(IrAnalyze *ira, IrInstruc
 
     switch (type_entry->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
             zig_unreachable();
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdUnreachable:
@@ -16461,21 +16441,23 @@ static TypeTableEntry *ir_analyze_instruction_fn_proto(IrAnalyze *ira, IrInstruc
                 zig_unreachable();
             }
         }
-        IrInstruction *param_type_value = instruction->param_types[fn_type_id.next_param_index]->other;
-        if (type_is_invalid(param_type_value->value.type))
-            return ira->codegen->builtin_types.entry_invalid;
-
         FnTypeParamInfo *param_info = &fn_type_id.param_info[fn_type_id.next_param_index];
         param_info->is_noalias = param_node->data.param_decl.is_noalias;
-        param_info->type = ir_resolve_type(ira, param_type_value);
-        if (type_is_invalid(param_info->type))
-            return ira->codegen->builtin_types.entry_invalid;
 
-        if (param_info->type->id == TypeTableEntryIdVar) {
+        if (instruction->param_types[fn_type_id.next_param_index] == nullptr) {
+            param_info->type = nullptr;
             ConstExprValue *out_val = ir_build_const_from(ira, &instruction->base);
             out_val->data.x_type = get_generic_fn_type(ira->codegen, &fn_type_id);
             return ira->codegen->builtin_types.entry_type;
+        } else {
+            IrInstruction *param_type_value = instruction->param_types[fn_type_id.next_param_index]->other;
+            if (type_is_invalid(param_type_value->value.type))
+                return ira->codegen->builtin_types.entry_invalid;
+            param_info->type = ir_resolve_type(ira, param_type_value);
+            if (type_is_invalid(param_info->type))
+                return ira->codegen->builtin_types.entry_invalid;
         }
+
     }
 
     if (instruction->align_value != nullptr) {
@@ -16869,7 +16851,6 @@ static void buf_write_value_bytes(CodeGen *codegen, uint8_t *buf, ConstExprValue
     assert(val->special == ConstValSpecialStatic);
     switch (val->type->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdOpaque:
         case TypeTableEntryIdBoundFn:
@@ -16937,7 +16918,6 @@ static void buf_read_value_bytes(CodeGen *codegen, uint8_t *buf, ConstExprValue
     assert(val->special == ConstValSpecialStatic);
     switch (val->type->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdOpaque:
         case TypeTableEntryIdBoundFn:
@@ -17014,7 +16994,6 @@ static TypeTableEntry *ir_analyze_instruction_bit_cast(IrAnalyze *ira, IrInstruc
 
     switch (src_type->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdOpaque:
         case TypeTableEntryIdBoundFn:
@@ -17041,7 +17020,6 @@ static TypeTableEntry *ir_analyze_instruction_bit_cast(IrAnalyze *ira, IrInstruc
 
     switch (dest_type->id) {
         case TypeTableEntryIdInvalid:
-        case TypeTableEntryIdVar:
         case TypeTableEntryIdMetaType:
         case TypeTableEntryIdOpaque:
         case TypeTableEntryIdBoundFn:

src/parser.cpp

@@ -263,21 +263,14 @@ static AstNode *ast_parse_error_set_expr(ParseContext *pc, size_t *token_index,
 }
 
 /*
-TypeExpr = ErrorSetExpr | "var"
+TypeExpr = ErrorSetExpr
 */
 static AstNode *ast_parse_type_expr(ParseContext *pc, size_t *token_index, bool mandatory) {
-    Token *token = &pc->tokens->at(*token_index);
+    return ast_parse_error_set_expr(pc, token_index, mandatory);
-    if (token->id == TokenIdKeywordVar) {
-        AstNode *node = ast_create_node(pc, NodeTypeVarLiteral, token);
-        *token_index += 1;
-        return node;
-    } else {
-        return ast_parse_error_set_expr(pc, token_index, mandatory);
-    }
 }
 
 /*
-ParamDecl = option("noalias" | "comptime") option(Symbol ":") (TypeExpr | "...")
+ParamDecl = option("noalias" | "comptime") option(Symbol ":") (TypeExpr | "var" | "...")
 */
 static AstNode *ast_parse_param_decl(ParseContext *pc, size_t *token_index) {
     Token *token = &pc->tokens->at(*token_index);
@@ -308,6 +301,9 @@ static AstNode *ast_parse_param_decl(ParseContext *pc, size_t *token_index) {
     if (ellipsis_tok->id == TokenIdEllipsis3) {
         *token_index += 1;
         node->data.param_decl.is_var_args = true;
+    } else if (ellipsis_tok->id == TokenIdKeywordVar) {
+        *token_index += 1;
+        node->data.param_decl.var_token = ellipsis_tok;
     } else {
         node->data.param_decl.type = ast_parse_type_expr(pc, token_index, true);
     }
@@ -2421,7 +2417,7 @@ static AstNode *ast_parse_block(ParseContext *pc, size_t *token_index, bool mand
 }
 
 /*
-FnProto = option("nakedcc" | "stdcallcc" | "extern" | ("async" option("(" Expression ")"))) "fn" option(Symbol) ParamDeclList option("align" "(" Expression ")") option("section" "(" Expression ")") option("!") TypeExpr
+FnProto = option("nakedcc" | "stdcallcc" | "extern" | ("async" option("(" Expression ")"))) "fn" option(Symbol) ParamDeclList option("align" "(" Expression ")") option("section" "(" Expression ")") option("!") (TypeExpr | "var")
 */
 static AstNode *ast_parse_fn_proto(ParseContext *pc, size_t *token_index, bool mandatory, VisibMod visib_mod) {
     Token *first_token = &pc->tokens->at(*token_index);
@@ -2507,19 +2503,25 @@ static AstNode *ast_parse_fn_proto(ParseContext *pc, size_t *token_index, bool m
         ast_eat_token(pc, token_index, TokenIdRParen);
         next_token = &pc->tokens->at(*token_index);
     }
-    if (next_token->id == TokenIdKeywordError) {
+    if (next_token->id == TokenIdKeywordVar) {
-        Token *maybe_lbrace_tok = &pc->tokens->at(*token_index + 1);
+        node->data.fn_proto.return_var_token = next_token;
-        if (maybe_lbrace_tok->id == TokenIdLBrace) {
-            *token_index += 1;
-            node->data.fn_proto.return_type = ast_create_node(pc, NodeTypeErrorType, next_token);
-            return node;
-        }
-    } else if (next_token->id == TokenIdBang) {
         *token_index += 1;
-        node->data.fn_proto.auto_err_set = true;
         next_token = &pc->tokens->at(*token_index);
+    } else {
+        if (next_token->id == TokenIdKeywordError) {
+            Token *maybe_lbrace_tok = &pc->tokens->at(*token_index + 1);
+            if (maybe_lbrace_tok->id == TokenIdLBrace) {
+                *token_index += 1;
+                node->data.fn_proto.return_type = ast_create_node(pc, NodeTypeErrorType, next_token);
+                return node;
+            }
+        } else if (next_token->id == TokenIdBang) {
+            *token_index += 1;
+            node->data.fn_proto.auto_err_set = true;
+            next_token = &pc->tokens->at(*token_index);
+        }
+        node->data.fn_proto.return_type = ast_parse_type_expr(pc, token_index, true);
     }
-    node->data.fn_proto.return_type = ast_parse_type_expr(pc, token_index, true);
 
     return node;
 }
@@ -3069,9 +3071,6 @@ void ast_visit_node_children(AstNode *node, void (*visit)(AstNode **, void *cont
         case NodeTypeErrorType:
             // none
             break;
-        case NodeTypeVarLiteral:
-            // none
-            break;
         case NodeTypeAddrOfExpr:
             visit_field(&node->data.addr_of_expr.align_expr, visit, context);
             visit_field(&node->data.addr_of_expr.op_expr, visit, context);

test/compile_errors.zig

@@ -1,6 +1,13 @@
 const tests = @import("tests.zig");
 
 pub fn addCases(cases: &tests.CompileErrorContext) void {
+    cases.add("var not allowed in structs",
+        \\export fn entry() void {
+        \\   var s = (struct{v: var}){.v=i32(10)};
+        \\}
+    ,
+        ".tmp_source.zig:2:23: error: invalid token: 'var'");
+
     cases.add("@ptrCast discards const qualifier",
         \\export fn entry() void {
         \\    const x: i32 = 1234;