diff --git a/src/Sema.zig b/src/Sema.zig index 9f425b7bcf..d31c0745ed 100644 --- a/src/Sema.zig +++ b/src/Sema.zig @@ -151,6 +151,8 @@ pub const Block = struct { runtime_index: Value.RuntimeIndex = .zero, inline_block: Zir.Inst.Index = 0, + comptime_reason: ?*const ComptimeReason = null, + // TODO is_comptime and comptime_reason should probably be merged together. is_comptime: bool, is_typeof: bool = false, is_coerce_result_ptr: bool = false, @@ -173,6 +175,49 @@ pub const Block = struct { /// Value for switch_capture in an inline case inline_case_capture: Air.Inst.Ref = .none, + const ComptimeReason = union(enum) { + c_import: struct { + block: *Block, + src: LazySrcLoc, + }, + comptime_ret_ty: struct { + block: *Block, + func: Air.Inst.Ref, + func_src: LazySrcLoc, + return_ty: Type, + }, + + fn explain(cr: ComptimeReason, sema: *Sema, msg: ?*Module.ErrorMsg) !void { + const parent = msg orelse return; + const prefix = "expression is evaluated at comptime because "; + switch (cr) { + .c_import => |ci| { + try sema.errNote(ci.block, ci.src, parent, prefix ++ "it is inside a @cImport", .{}); + }, + .comptime_ret_ty => |rt| { + const src_loc = if (try sema.funcDeclSrc(rt.block, rt.func_src, rt.func)) |capture| blk: { + var src_loc = capture; + src_loc.lazy = .{ .node_offset_fn_type_ret_ty = 0 }; + break :blk src_loc; + } else blk: { + const src_decl = sema.mod.declPtr(rt.block.src_decl); + break :blk rt.func_src.toSrcLoc(src_decl); + }; + if (rt.return_ty.tag() == .generic_poison) { + return sema.mod.errNoteNonLazy(src_loc, parent, prefix ++ "the generic function was instantiated with a comptime-only return type", .{}); + } + try sema.mod.errNoteNonLazy( + src_loc, + parent, + prefix ++ "the function returns a comptime-only type '{}'", + .{rt.return_ty.fmt(sema.mod)}, + ); + try sema.explainWhyTypeIsComptime(rt.block, rt.func_src, parent, src_loc, rt.return_ty); + }, + } + } + }; + const Param = struct { /// `noreturn` means `anytype`. ty: Type, @@ -224,6 +269,7 @@ pub const Block = struct { .label = null, .inlining = parent.inlining, .is_comptime = parent.is_comptime, + .comptime_reason = parent.comptime_reason, .is_typeof = parent.is_typeof, .runtime_cond = parent.runtime_cond, .runtime_loop = parent.runtime_loop, @@ -1420,7 +1466,10 @@ fn analyzeBodyInner( const extra = sema.code.extraData(Zir.Inst.CondBr, inst_data.payload_index); const then_body = sema.code.extra[extra.end..][0..extra.data.then_body_len]; const else_body = sema.code.extra[extra.end + then_body.len ..][0..extra.data.else_body_len]; - const cond = try sema.resolveInstConst(block, cond_src, extra.data.condition, "condition in comptime branch must be comptime-known"); + const cond = sema.resolveInstConst(block, cond_src, extra.data.condition, "condition in comptime branch must be comptime-known") catch |err| { + if (err == error.AnalysisFail and block.comptime_reason != null) try block.comptime_reason.?.explain(sema, sema.err); + return err; + }; const inline_body = if (cond.val.toBool()) then_body else else_body; try sema.maybeErrorUnwrapCondbr(block, inline_body, extra.data.condition, cond_src); @@ -1438,7 +1487,10 @@ fn analyzeBodyInner( const extra = sema.code.extraData(Zir.Inst.CondBr, inst_data.payload_index); const then_body = sema.code.extra[extra.end..][0..extra.data.then_body_len]; const else_body = sema.code.extra[extra.end + then_body.len ..][0..extra.data.else_body_len]; - const cond = try sema.resolveInstConst(block, cond_src, extra.data.condition, "condition in comptime branch must be comptime-known"); + const cond = sema.resolveInstConst(block, cond_src, extra.data.condition, "condition in comptime branch must be comptime-known") catch |err| { + if (err == error.AnalysisFail and block.comptime_reason != null) try block.comptime_reason.?.explain(sema, sema.err); + return err; + }; const inline_body = if (cond.val.toBool()) then_body else else_body; const old_runtime_index = block.runtime_index; defer block.runtime_index = old_runtime_index; @@ -1460,7 +1512,10 @@ fn analyzeBodyInner( const err_union = try sema.resolveInst(extra.data.operand); const is_non_err = try sema.analyzeIsNonErrComptimeOnly(block, operand_src, err_union); assert(is_non_err != .none); - const is_non_err_tv = try sema.resolveInstConst(block, operand_src, is_non_err, "try operand inside comptime block must be comptime-known"); + const is_non_err_tv = sema.resolveInstConst(block, operand_src, is_non_err, "try operand inside comptime block must be comptime-known") catch |err| { + if (err == error.AnalysisFail and block.comptime_reason != null) try block.comptime_reason.?.explain(sema, sema.err); + return err; + }; if (is_non_err_tv.val.toBool()) { const err_union_ty = sema.typeOf(err_union); break :blk try sema.analyzeErrUnionPayload(block, src, err_union_ty, err_union, operand_src, false); @@ -1516,7 +1571,10 @@ fn analyzeBodyInner( const err_union = try sema.analyzeLoad(block, src, operand, operand_src); const is_non_err = try sema.analyzeIsNonErrComptimeOnly(block, operand_src, err_union); assert(is_non_err != .none); - const is_non_err_tv = try sema.resolveInstConst(block, operand_src, is_non_err, "try operand inside comptime block must be comptime-known"); + const is_non_err_tv = sema.resolveInstConst(block, operand_src, is_non_err, "try operand inside comptime block must be comptime-known") catch |err| { + if (err == error.AnalysisFail and block.comptime_reason != null) try block.comptime_reason.?.explain(sema, sema.err); + return err; + }; if (is_non_err_tv.val.toBool()) { break :blk try sema.analyzeErrUnionPayloadPtr(block, src, operand, false, false); } @@ -1675,8 +1733,8 @@ pub fn setupErrorReturnTrace(sema: *Sema, block: *Block, last_arg_index: usize) return; } + assert(!block.is_comptime); var err_trace_block = block.makeSubBlock(); - err_trace_block.is_comptime = false; defer err_trace_block.instructions.deinit(sema.gpa); const src: LazySrcLoc = .unneeded; @@ -4944,6 +5002,10 @@ fn zirCImport(sema: *Sema, parent_block: *Block, inst: Zir.Inst.Index) CompileEr var c_import_buf = std.ArrayList(u8).init(sema.gpa); defer c_import_buf.deinit(); + var comptime_reason = .{ .c_import = .{ + .block = parent_block, + .src = src, + } }; var child_block: Block = .{ .parent = parent_block, .sema = sema, @@ -4952,7 +5014,8 @@ fn zirCImport(sema: *Sema, parent_block: *Block, inst: Zir.Inst.Index) CompileEr .wip_capture_scope = parent_block.wip_capture_scope, .instructions = .{}, .inlining = parent_block.inlining, - .is_comptime = parent_block.is_comptime, + .is_comptime = true, + .comptime_reason = &comptime_reason, .c_import_buf = &c_import_buf, .runtime_cond = parent_block.runtime_cond, .runtime_loop = parent_block.runtime_loop, @@ -5053,6 +5116,7 @@ fn zirBlock(sema: *Sema, parent_block: *Block, inst: Zir.Inst.Index) CompileErro .label = &label, .inlining = parent_block.inlining, .is_comptime = parent_block.is_comptime, + .comptime_reason = parent_block.comptime_reason, .is_typeof = parent_block.is_typeof, .want_safety = parent_block.want_safety, .float_mode = parent_block.float_mode, @@ -5926,6 +5990,7 @@ fn zirCall( defer block.is_comptime = parent_comptime; if (arg_index < fn_params_len and func_ty_info.comptime_params[arg_index]) { block.is_comptime = true; + // TODO set comptime_reason } const param_ty_inst = try sema.addType(param_ty); @@ -6056,37 +6121,6 @@ const GenericCallAdapter = struct { } }; -fn addComptimeReturnTypeNote( - sema: *Sema, - block: *Block, - func: Air.Inst.Ref, - func_src: LazySrcLoc, - return_ty: Type, - parent: *Module.ErrorMsg, - requires_comptime: bool, -) !void { - if (!requires_comptime) return; - - const src_loc = if (try sema.funcDeclSrc(block, func_src, func)) |capture| blk: { - var src_loc = capture; - src_loc.lazy = .{ .node_offset_fn_type_ret_ty = 0 }; - break :blk src_loc; - } else blk: { - const src_decl = sema.mod.declPtr(block.src_decl); - break :blk func_src.toSrcLoc(src_decl); - }; - if (return_ty.tag() == .generic_poison) { - return sema.mod.errNoteNonLazy(src_loc, parent, "generic function is instantiated with a comptime-only return type", .{}); - } - try sema.mod.errNoteNonLazy( - src_loc, - parent, - "function is being called at comptime because it returns a comptime-only type '{}'", - .{return_ty.fmt(sema.mod)}, - ); - try sema.explainWhyTypeIsComptime(block, func_src, parent, src_loc, return_ty); -} - fn analyzeCall( sema: *Sema, block: *Block, @@ -6177,11 +6211,21 @@ fn analyzeCall( var is_generic_call = func_ty_info.is_generic; var is_comptime_call = block.is_comptime or modifier == .compile_time; - var comptime_only_ret_ty = false; + var comptime_reason_buf: Block.ComptimeReason = undefined; + var comptime_reason: ?*const Block.ComptimeReason = null; if (!is_comptime_call) { if (sema.typeRequiresComptime(func_ty_info.return_type)) |ct| { is_comptime_call = ct; - comptime_only_ret_ty = ct; + if (ct) { + // stage1 can't handle doing this directly + comptime_reason_buf = .{ .comptime_ret_ty = .{ + .block = block, + .func = func, + .func_src = func_src, + .return_ty = func_ty_info.return_type, + } }; + comptime_reason = &comptime_reason_buf; + } } else |err| switch (err) { error.GenericPoison => is_generic_call = true, else => |e| return e, @@ -6210,7 +6254,14 @@ fn analyzeCall( error.ComptimeReturn => { is_inline_call = true; is_comptime_call = true; - comptime_only_ret_ty = true; + // stage1 can't handle doing this directly + comptime_reason_buf = .{ .comptime_ret_ty = .{ + .block = block, + .func = func, + .func_src = func_src, + .return_ty = func_ty_info.return_type, + } }; + comptime_reason = &comptime_reason_buf; }, else => |e| return e, } @@ -6222,9 +6273,7 @@ fn analyzeCall( const result: Air.Inst.Ref = if (is_inline_call) res: { const func_val = sema.resolveConstValue(block, func_src, func, "function being called at comptime must be comptime-known") catch |err| { - if (err == error.AnalysisFail and sema.err != null) { - try sema.addComptimeReturnTypeNote(block, func, func_src, func_ty_info.return_type, sema.err.?, comptime_only_ret_ty); - } + if (err == error.AnalysisFail and comptime_reason != null) try comptime_reason.?.explain(sema, sema.err); return err; }; const module_fn = switch (func_val.tag()) { @@ -6292,6 +6341,7 @@ fn analyzeCall( .label = null, .inlining = &inlining, .is_comptime = is_comptime_call, + .comptime_reason = comptime_reason, .error_return_trace_index = block.error_return_trace_index, }; @@ -6344,11 +6394,6 @@ fn analyzeCall( is_comptime_call, &should_memoize, memoized_call_key, - // last 4 arguments are only used when reporting errors - undefined, - undefined, - undefined, - undefined, ) catch |err| switch (err) { error.NeededSourceLocation => { _ = sema.inst_map.remove(inst); @@ -6364,10 +6409,6 @@ fn analyzeCall( is_comptime_call, &should_memoize, memoized_call_key, - func, - func_src, - func_ty_info.return_type, - comptime_only_ret_ty, ); return error.AnalysisFail; }, @@ -6604,10 +6645,6 @@ fn analyzeInlineCallArg( is_comptime_call: bool, should_memoize: *bool, memoized_call_key: Module.MemoizedCall.Key, - func: Air.Inst.Ref, - func_src: LazySrcLoc, - ret_ty: Type, - comptime_only_ret_ty: bool, ) !void { const zir_tags = sema.code.instructions.items(.tag); switch (zir_tags[inst]) { @@ -6624,9 +6661,7 @@ fn analyzeInlineCallArg( const uncasted_arg = uncasted_args[arg_i.*]; if (try sema.typeRequiresComptime(param_ty)) { _ = sema.resolveConstMaybeUndefVal(arg_block, arg_src, uncasted_arg, "argument to parameter with comptime-only type must be comptime-known") catch |err| { - if (err == error.AnalysisFail and sema.err != null) { - try sema.addComptimeReturnTypeNote(arg_block, func, func_src, ret_ty, sema.err.?, comptime_only_ret_ty); - } + if (err == error.AnalysisFail and param_block.comptime_reason != null) try param_block.comptime_reason.?.explain(sema, sema.err); return err; }; } @@ -6635,9 +6670,7 @@ fn analyzeInlineCallArg( if (is_comptime_call) { try sema.inst_map.putNoClobber(sema.gpa, inst, casted_arg); const arg_val = sema.resolveConstMaybeUndefVal(arg_block, arg_src, casted_arg, "argument to function being called at comptime must be comptime-known") catch |err| { - if (err == error.AnalysisFail and sema.err != null) { - try sema.addComptimeReturnTypeNote(arg_block, func, func_src, ret_ty, sema.err.?, comptime_only_ret_ty); - } + if (err == error.AnalysisFail and param_block.comptime_reason != null) try param_block.comptime_reason.?.explain(sema, sema.err); return err; }; switch (arg_val.tag()) { @@ -6679,9 +6712,7 @@ fn analyzeInlineCallArg( if (is_comptime_call) { try sema.inst_map.putNoClobber(sema.gpa, inst, uncasted_arg); const arg_val = sema.resolveConstMaybeUndefVal(arg_block, arg_src, uncasted_arg, "argument to function being called at comptime must be comptime-known") catch |err| { - if (err == error.AnalysisFail and sema.err != null) { - try sema.addComptimeReturnTypeNote(arg_block, func, func_src, ret_ty, sema.err.?, comptime_only_ret_ty); - } + if (err == error.AnalysisFail and param_block.comptime_reason != null) try param_block.comptime_reason.?.explain(sema, sema.err); return err; }; switch (arg_val.tag()) { @@ -10223,6 +10254,7 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError .label = &label, .inlining = block.inlining, .is_comptime = block.is_comptime, + .comptime_reason = block.comptime_reason, .is_typeof = block.is_typeof, .switch_else_err_ty = else_error_ty, .runtime_cond = block.runtime_cond, @@ -10333,7 +10365,13 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError return sema.resolveBlockBody(block, src, &child_block, special.body, inst, merges); } - try sema.requireRuntimeBlock(block, src, operand_src); + if (child_block.is_comptime) { + _ = sema.resolveConstValue(&child_block, operand_src, operand, "condition in comptime switch must be comptime-known") catch |err| { + if (err == error.AnalysisFail and child_block.comptime_reason != null) try child_block.comptime_reason.?.explain(sema, sema.err); + return err; + }; + unreachable; + } const estimated_cases_extra = (scalar_cases_len + multi_cases_len) * @typeInfo(Air.SwitchBr.Case).Struct.fields.len + 2; @@ -21469,6 +21507,9 @@ fn requireRuntimeBlock(sema: *Sema, block: *Block, src: LazySrcLoc, runtime_src: if (runtime_src) |some| { try sema.errNote(block, some, msg, "operation is runtime due to this operand", .{}); } + if (block.comptime_reason) |some| { + try some.explain(sema, msg); + } break :msg msg; }; return sema.failWithOwnedErrorMsg(msg); @@ -21940,6 +21981,7 @@ fn addSafetyCheck( panic_id: PanicId, ) !void { const gpa = sema.gpa; + assert(!parent_block.is_comptime); var fail_block: Block = .{ .parent = parent_block, @@ -21949,7 +21991,7 @@ fn addSafetyCheck( .wip_capture_scope = parent_block.wip_capture_scope, .instructions = .{}, .inlining = parent_block.inlining, - .is_comptime = parent_block.is_comptime, + .is_comptime = false, }; defer fail_block.instructions.deinit(gpa); @@ -22061,6 +22103,7 @@ fn panicUnwrapError( unwrap_err_tag: Air.Inst.Tag, is_non_err_tag: Air.Inst.Tag, ) !void { + assert(!parent_block.is_comptime); const ok = try parent_block.addUnOp(is_non_err_tag, operand); const gpa = sema.gpa; @@ -22072,7 +22115,7 @@ fn panicUnwrapError( .wip_capture_scope = parent_block.wip_capture_scope, .instructions = .{}, .inlining = parent_block.inlining, - .is_comptime = parent_block.is_comptime, + .is_comptime = false, }; defer fail_block.instructions.deinit(gpa); @@ -22104,6 +22147,7 @@ fn panicIndexOutOfBounds( len: Air.Inst.Ref, cmp_op: Air.Inst.Tag, ) !void { + assert(!parent_block.is_comptime); const ok = try parent_block.addBinOp(cmp_op, index, len); const gpa = sema.gpa; @@ -22115,7 +22159,7 @@ fn panicIndexOutOfBounds( .wip_capture_scope = parent_block.wip_capture_scope, .instructions = .{}, .inlining = parent_block.inlining, - .is_comptime = parent_block.is_comptime, + .is_comptime = false, }; defer fail_block.instructions.deinit(gpa); @@ -22146,6 +22190,7 @@ fn panicSentinelMismatch( ptr: Air.Inst.Ref, sentinel_index: Air.Inst.Ref, ) !void { + assert(!parent_block.is_comptime); const expected_sentinel_val = maybe_sentinel orelse return; const expected_sentinel = try sema.addConstant(sentinel_ty, expected_sentinel_val); @@ -22186,7 +22231,7 @@ fn panicSentinelMismatch( .wip_capture_scope = parent_block.wip_capture_scope, .instructions = .{}, .inlining = parent_block.inlining, - .is_comptime = parent_block.is_comptime, + .is_comptime = false, }; defer fail_block.instructions.deinit(gpa); diff --git a/test/cases/compile_errors/condition_comptime_reason_explained.zig b/test/cases/compile_errors/condition_comptime_reason_explained.zig new file mode 100644 index 0000000000..332ae8afc8 --- /dev/null +++ b/test/cases/compile_errors/condition_comptime_reason_explained.zig @@ -0,0 +1,48 @@ +const S = struct { + fnPtr: fn () void, +}; +fn bar() void {} +fn baz() void {} +var runtime: bool = true; +fn ifExpr() S { + if (runtime) { + return .{ + .fnPtr = bar, + }; + } else { + return .{ + .fnPtr = baz, + }; + } +} +pub export fn entry1() void { + _ = ifExpr(); +} +fn switchExpr() S { + switch (runtime) { + true => return .{ + .fnPtr = bar, + }, + false => return .{ + .fnPtr = baz, + }, + } +} +pub export fn entry2() void { + _ = switchExpr(); +} + +// error +// backend=stage2 +// target=native +// +// :8:9: error: unable to resolve comptime value +// :8:9: note: condition in comptime branch must be comptime-known +// :7:13: note: expression is evaluated at comptime because the function returns a comptime-only type 'tmp.S' +// :2:12: note: struct requires comptime because of this field +// :2:12: note: use '*const fn() void' for a function pointer type +// :19:15: note: called from here +// :22:13: error: unable to resolve comptime value +// :22:13: note: condition in comptime switch must be comptime-known +// :21:17: note: expression is evaluated at comptime because the function returns a comptime-only type 'tmp.S' +// :32:19: note: called from here diff --git a/test/cases/compile_errors/explain_why_fn_is_called_at_comptime.zig b/test/cases/compile_errors/explain_why_fn_is_called_at_comptime.zig index d19ab31617..83d5d7e33f 100644 --- a/test/cases/compile_errors/explain_why_fn_is_called_at_comptime.zig +++ b/test/cases/compile_errors/explain_why_fn_is_called_at_comptime.zig @@ -18,6 +18,6 @@ pub export fn entry() void { // // :12:13: error: unable to resolve comptime value // :12:13: note: argument to function being called at comptime must be comptime-known -// :7:25: note: function is being called at comptime because it returns a comptime-only type 'tmp.S' +// :7:25: note: expression is evaluated at comptime because the function returns a comptime-only type 'tmp.S' // :2:12: note: struct requires comptime because of this field // :2:12: note: use '*const fn() void' for a function pointer type diff --git a/test/cases/compile_errors/explain_why_generic_fn_is_called_at_comptime.zig b/test/cases/compile_errors/explain_why_generic_fn_is_called_at_comptime.zig index 36aeb40479..701241a403 100644 --- a/test/cases/compile_errors/explain_why_generic_fn_is_called_at_comptime.zig +++ b/test/cases/compile_errors/explain_why_generic_fn_is_called_at_comptime.zig @@ -19,4 +19,4 @@ pub export fn entry() void { // // :14:13: error: unable to resolve comptime value // :14:13: note: argument to function being called at comptime must be comptime-known -// :9:38: note: generic function is instantiated with a comptime-only return type +// :9:38: note: expression is evaluated at comptime because the generic function was instantiated with a comptime-only return type diff --git a/test/cases/compile_errors/unable_to_evaluate_expr_inside_cimport.zig b/test/cases/compile_errors/unable_to_evaluate_expr_inside_cimport.zig new file mode 100644 index 0000000000..9460a58993 --- /dev/null +++ b/test/cases/compile_errors/unable_to_evaluate_expr_inside_cimport.zig @@ -0,0 +1,15 @@ +const c = @cImport({ + _ = 1 + foo; +}); +extern var foo: i32; +export fn entry() void { + _ = c; +} + +// error +// backend=llvm +// target=native +// +// :2:11: error: unable to evaluate comptime expression +// :2:13: note: operation is runtime due to this operand +// :1:11: note: expression is evaluated at comptime because it is inside a @cImport diff --git a/test/compile_errors.zig b/test/compile_errors.zig index e9b08565ce..5454124df8 100644 --- a/test/compile_errors.zig +++ b/test/compile_errors.zig @@ -204,7 +204,7 @@ pub fn addCases(ctx: *TestContext) !void { , &[_][]const u8{ ":3:12: error: unable to resolve comptime value", ":3:12: note: argument to function being called at comptime must be comptime-known", - ":2:55: note: generic function is instantiated with a comptime-only return type", + ":2:55: note: expression is evaluated at comptime because the generic function was instantiated with a comptime-only return type", }); }