Add `-vet-extra` (checks for unneeded casts and transmutes)

src/build_settings.cpp

@@ -190,6 +190,7 @@ struct BuildContext {
 	bool   no_entry_point;
 	bool   use_lld;
 	bool   vet;
+	bool   vet_extra;
 	bool   cross_compiling;
 	bool   different_os;
 	bool   keep_object_files;

src/check_expr.cpp

@@ -2388,6 +2388,14 @@ void check_cast(CheckerContext *c, Operand *x, Type *type) {
 		update_expr_type(c, x->expr, final_type, true);
 	}
 
+	if (build_context.vet_extra) {
+		if (are_types_identical(x->type, type)) {
+			gbString str = type_to_string(type);
+			warning(x->expr, "Unneeded cast to the same type '%s'", str);
+			gb_string_free(str);
+		}
+	}
+
 	x->type = type;
 }
 
@@ -2429,6 +2437,14 @@ bool check_transmute(CheckerContext *c, Ast *node, Operand *o, Type *t) {
 		return false;
 	}
 
+	if (build_context.vet_extra) {
+		if (are_types_identical(o->type, t)) {
+			gbString str = type_to_string(t);
+			warning(o->expr, "Unneeded transmute to the same type '%s'", str);
+			gb_string_free(str);
+		}
+	}
+
 	o->mode = Addressing_Value;
 	o->type = t;
 	return true;

src/llvm_backend.hpp

@@ -61,9 +61,6 @@ struct lbAddr {
 			Type *type;
 			Type *result;
 		} map;
-		struct {
-			i32 value_index;
-		} bit_field;
 		struct {
 			Selection sel;
 		} ctx;

src/main.cpp

@@ -593,6 +593,7 @@ enum BuildFlagKind {
 	BuildFlag_NoEntryPoint,
 	BuildFlag_UseLLD,
 	BuildFlag_Vet,
+	BuildFlag_VetExtra,
 	BuildFlag_UseLLVMApi,
 	BuildFlag_IgnoreUnknownAttributes,
 	BuildFlag_ExtraLinkerFlags,
@@ -706,6 +707,7 @@ bool parse_build_flags(Array<String> args) {
 	add_flag(&build_flags, BuildFlag_NoEntryPoint,      str_lit("no-entry-point"),      BuildFlagParam_None, Command__does_check &~ Command_test);
 	add_flag(&build_flags, BuildFlag_UseLLD,            str_lit("lld"),                 BuildFlagParam_None, Command__does_build);
 	add_flag(&build_flags, BuildFlag_Vet,               str_lit("vet"),                 BuildFlagParam_None, Command__does_check);
+	add_flag(&build_flags, BuildFlag_VetExtra,          str_lit("vet-extra"),           BuildFlagParam_None, Command__does_check);
 	add_flag(&build_flags, BuildFlag_UseLLVMApi,        str_lit("llvm-api"),            BuildFlagParam_None, Command__does_build);
 	add_flag(&build_flags, BuildFlag_IgnoreUnknownAttributes, str_lit("ignore-unknown-attributes"), BuildFlagParam_None, Command__does_check);
 	add_flag(&build_flags, BuildFlag_ExtraLinkerFlags,  str_lit("extra-linker-flags"),              BuildFlagParam_String, Command__does_build);
@@ -1151,6 +1153,10 @@ bool parse_build_flags(Array<String> args) {
 						case BuildFlag_Vet:
 							build_context.vet = true;
 							break;
+						case BuildFlag_VetExtra:
+							build_context.vet = true;
+							build_context.vet_extra = true;
+							break;
 
 						case BuildFlag_UseLLVMApi:
 							build_context.use_llvm_api = true;
@@ -1694,6 +1700,11 @@ void print_show_help(String const arg0, String const &command) {
 		print_usage_line(3, "Unused declarations");
 		print_usage_line(0, "");
 
+		print_usage_line(1, "-vet-extra");
+		print_usage_line(2, "Do even more checks than standard vet on the code");
+		print_usage_line(2, "To treat the extra warnings as errors, use -warnings-as-errors");
+		print_usage_line(0, "");
+
 		print_usage_line(1, "-ignore-unknown-attributes");
 		print_usage_line(2, "Ignores unknown attributes");
 		print_usage_line(2, "This can be used with metaprogramming tools");