diff options
Diffstat (limited to 'src/AstGen.zig')
| -rw-r--r-- | src/AstGen.zig | 60 |
1 files changed, 44 insertions, 16 deletions
diff --git a/src/AstGen.zig b/src/AstGen.zig index 5638216ed1..0d1fa6c061 100644 --- a/src/AstGen.zig +++ b/src/AstGen.zig @@ -1226,7 +1226,7 @@ fn awaitExpr( try astgen.errNoteNode(gz.suspend_node, "suspend block here", .{}), }); } - const operand = try expr(gz, scope, .{ .rl = .none }, rhs_node); + const operand = try expr(gz, scope, .{ .rl = .ref }, rhs_node); const result = if (gz.nosuspend_node != 0) try gz.addExtendedPayload(.await_nosuspend, Zir.Inst.UnNode{ .node = gz.nodeIndexToRelative(node), @@ -1248,7 +1248,7 @@ fn resumeExpr( const tree = astgen.tree; const node_datas = tree.nodes.items(.data); const rhs_node = node_datas[node].lhs; - const operand = try expr(gz, scope, .{ .rl = .none }, rhs_node); + const operand = try expr(gz, scope, .{ .rl = .ref }, rhs_node); const result = try gz.addUnNode(.@"resume", operand, node); return rvalue(gz, ri, result, node); } @@ -1971,6 +1971,17 @@ fn comptimeExpr( .block_two, .block_two_semicolon, .block, .block_semicolon => { const token_tags = tree.tokens.items(.tag); const lbrace = main_tokens[node]; + // Careful! We can't pass in the real result location here, since it may + // refer to runtime memory. A runtime-to-comptime boundary has to remove + // result location information, compute the result, and copy it to the true + // result location at runtime. We do this below as well. + const ty_only_ri: ResultInfo = .{ + .ctx = ri.ctx, + .rl = if (try ri.rl.resultType(gz, node)) |res_ty| + .{ .coerced_ty = res_ty } + else + .none, + }; if (token_tags[lbrace - 1] == .colon and token_tags[lbrace - 2] == .identifier) { @@ -1985,17 +1996,13 @@ fn comptimeExpr( else stmts[0..2]; - // Careful! We can't pass in the real result location here, since it may - // refer to runtime memory. A runtime-to-comptime boundary has to remove - // result location information, compute the result, and copy it to the true - // result location at runtime. We do this below as well. - const block_ref = try labeledBlockExpr(gz, scope, .{ .rl = .none }, node, stmt_slice, true); + const block_ref = try labeledBlockExpr(gz, scope, ty_only_ri, node, stmt_slice, true); return rvalue(gz, ri, block_ref, node); }, .block, .block_semicolon => { const stmts = tree.extra_data[node_datas[node].lhs..node_datas[node].rhs]; // Replace result location and copy back later - see above. - const block_ref = try labeledBlockExpr(gz, scope, .{ .rl = .none }, node, stmts, true); + const block_ref = try labeledBlockExpr(gz, scope, ty_only_ri, node, stmts, true); return rvalue(gz, ri, block_ref, node); }, else => unreachable, @@ -2013,7 +2020,14 @@ fn comptimeExpr( const block_inst = try gz.makeBlockInst(.block_comptime, node); // Replace result location and copy back later - see above. - const block_result = try expr(&block_scope, scope, .{ .rl = .none }, node); + const ty_only_ri: ResultInfo = .{ + .ctx = ri.ctx, + .rl = if (try ri.rl.resultType(gz, node)) |res_ty| + .{ .coerced_ty = res_ty } + else + .none, + }; + const block_result = try expr(&block_scope, scope, ty_only_ri, node); if (!gz.refIsNoReturn(block_result)) { _ = try block_scope.addBreak(.@"break", block_inst, block_result); } @@ -2941,11 +2955,19 @@ fn checkUsed(gz: *GenZir, outer_scope: *Scope, inner_scope: *Scope) InnerError!v const s = scope.cast(Scope.LocalPtr).?; if (s.used == 0 and s.discarded == 0) { try astgen.appendErrorTok(s.token_src, "unused {s}", .{@tagName(s.id_cat)}); - } else if (s.used != 0 and s.discarded != 0) { - try astgen.appendErrorTokNotes(s.discarded, "pointless discard of {s}", .{@tagName(s.id_cat)}, &[_]u32{ - try gz.astgen.errNoteTok(s.used, "used here", .{}), - }); + } else { + if (s.used != 0 and s.discarded != 0) { + try astgen.appendErrorTokNotes(s.discarded, "pointless discard of {s}", .{@tagName(s.id_cat)}, &[_]u32{ + try astgen.errNoteTok(s.used, "used here", .{}), + }); + } + if (s.id_cat == .@"local variable" and !s.used_as_lvalue) { + try astgen.appendErrorTokNotes(s.token_src, "local variable is never mutated", .{}, &.{ + try astgen.errNoteTok(s.token_src, "consider using 'const'", .{}), + }); + } } + scope = s.parent; }, .defer_normal, .defer_error => scope = scope.cast(Scope.Defer).?.parent, @@ -6699,7 +6721,7 @@ fn forExpr( }; } - var then_node = for_full.ast.then_expr; + const then_node = for_full.ast.then_expr; var then_scope = parent_gz.makeSubBlock(&cond_scope.base); defer then_scope.unstack(); @@ -7579,7 +7601,10 @@ fn localVarRef( ); switch (ri.rl) { - .ref, .ref_coerced_ty => return ptr_inst, + .ref, .ref_coerced_ty => { + local_ptr.used_as_lvalue = true; + return ptr_inst; + }, else => { const loaded = try gz.addUnNode(.load, ptr_inst, ident); return rvalueNoCoercePreRef(gz, ri, loaded, ident); @@ -8149,7 +8174,7 @@ fn typeOf( } const payload_size: u32 = std.meta.fields(Zir.Inst.TypeOfPeer).len; const payload_index = try reserveExtra(astgen, payload_size + args.len); - var args_index = payload_index + payload_size; + const args_index = payload_index + payload_size; const typeof_inst = try gz.addExtendedMultiOpPayloadIndex(.typeof_peer, payload_index, args.len); @@ -10948,6 +10973,9 @@ const Scope = struct { /// Track the identifier where it is discarded, like this `_ = foo;`. /// 0 means never discarded. discarded: Ast.TokenIndex = 0, + /// Whether this value is used as an lvalue after inititialization. + /// If not, we know it can be `const`, so will emit a compile error if it is `var`. + used_as_lvalue: bool = false, /// String table index. name: u32, id_cat: IdCat, |