Merge pull request #14477 from Vexu/fixes

Improve `@ptrCast` errors, fix some bugs

6 files changed, 148 insertions, 12 deletions

diff --git a/src/AstGen.zig b/src/AstGen.zig
index 15b3611a1e..10673a2b37 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -2530,6 +2530,7 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .bit_size_of,
             .typeof_log2_int_type,
             .ptr_to_int,
+            .qual_cast,
             .align_of,
             .bool_to_int,
             .embed_file,
@@ -4278,7 +4279,34 @@ fn testDecl(
             var num_namespaces_out: u32 = 0;
             var capturing_namespace: ?*Scope.Namespace = null;
             while (true) switch (s.tag) {
-                .local_val, .local_ptr => unreachable, // a test cannot be in a local scope
+                .local_val => {
+                    const local_val = s.cast(Scope.LocalVal).?;
+                    if (local_val.name == name_str_index) {
+                        local_val.used = test_name_token;
+                        return astgen.failTokNotes(test_name_token, "cannot test a {s}", .{
+                            @tagName(local_val.id_cat),
+                        }, &[_]u32{
+                            try astgen.errNoteTok(local_val.token_src, "{s} declared here", .{
+                                @tagName(local_val.id_cat),
+                            }),
+                        });
+                    }
+                    s = local_val.parent;
+                },
+                .local_ptr => {
+                    const local_ptr = s.cast(Scope.LocalPtr).?;
+                    if (local_ptr.name == name_str_index) {
+                        local_ptr.used = test_name_token;
+                        return astgen.failTokNotes(test_name_token, "cannot test a {s}", .{
+                            @tagName(local_ptr.id_cat),
+                        }, &[_]u32{
+                            try astgen.errNoteTok(local_ptr.token_src, "{s} declared here", .{
+                                @tagName(local_ptr.id_cat),
+                            }),
+                        });
+                    }
+                    s = local_ptr.parent;
+                },
                 .gen_zir => s = s.cast(GenZir).?.parent,
                 .defer_normal, .defer_error => s = s.cast(Scope.Defer).?.parent,
                 .namespace, .enum_namespace => {
@@ -8010,6 +8038,7 @@ fn builtinCall(
         .float_cast   => return typeCast(gz, scope, ri, node, params[0], params[1], .float_cast),
         .int_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .int_cast),
         .ptr_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .ptr_cast),
+        .qual_cast    => return typeCast(gz, scope, ri, node, params[0], params[1], .qual_cast),
         .truncate     => return typeCast(gz, scope, ri, node, params[0], params[1], .truncate),
         // zig fmt: on
 
@@ -8692,6 +8721,7 @@ fn callExpr(
         defer arg_block.unstack();
 
         // `call_inst` is reused to provide the param type.
+        arg_block.rl_ty_inst = call_inst;
         const arg_ref = try expr(&arg_block, &arg_block.base, .{ .rl = .{ .coerced_ty = call_inst }, .ctx = .fn_arg }, param_node);
         _ = try arg_block.addBreak(.break_inline, call_index, arg_ref);
 
@@ -10840,7 +10870,12 @@ const GenZir = struct {
         // we emit ZIR for the block break instructions to have the result values,
         // and then rvalue() on that to pass the value to the result location.
         switch (parent_ri.rl) {
-            .ty, .coerced_ty => |ty_inst| {
+            .coerced_ty => |ty_inst| {
+                // Type coercion needs to happend before breaks.
+                gz.rl_ty_inst = ty_inst;
+                gz.break_result_info = .{ .rl = .{ .ty = ty_inst } };
+            },
+            .ty => |ty_inst| {
                 gz.rl_ty_inst = ty_inst;
                 gz.break_result_info = parent_ri;
             },
diff --git a/src/BuiltinFn.zig b/src/BuiltinFn.zig
index b71d96c3dd..80eb739185 100644
--- a/src/BuiltinFn.zig
+++ b/src/BuiltinFn.zig
@@ -75,6 +75,7 @@ pub const Tag = enum {
     prefetch,
     ptr_cast,
     ptr_to_int,
+    qual_cast,
     rem,
     return_address,
     select,
@@ -675,6 +676,13 @@ pub const list = list: {
             },
         },
         .{
+            "@qualCast",
+            .{
+                .tag = .qual_cast,
+                .param_count = 2,
+            },
+        },
+        .{
             "@rem",
             .{
                 .tag = .rem,
diff --git a/src/Sema.zig b/src/Sema.zig
index 610f1bf5af..b7b3a55063 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -1015,6 +1015,7 @@ fn analyzeBodyInner(
             .float_cast                   => try sema.zirFloatCast(block, inst),
             .int_cast                     => try sema.zirIntCast(block, inst),
             .ptr_cast                     => try sema.zirPtrCast(block, inst),
+            .qual_cast                    => try sema.zirQualCast(block, inst),
             .truncate                     => try sema.zirTruncate(block, inst),
             .align_cast                   => try sema.zirAlignCast(block, inst),
             .has_decl                     => try sema.zirHasDecl(block, inst),
@@ -3294,7 +3295,7 @@ fn ensureResultUsed(
             const msg = msg: {
                 const msg = try sema.errMsg(block, src, "error is ignored", .{});
                 errdefer msg.destroy(sema.gpa);
-                try sema.errNote(block, src, msg, "consider using `try`, `catch`, or `if`", .{});
+                try sema.errNote(block, src, msg, "consider using 'try', 'catch', or 'if'", .{});
                 break :msg msg;
             };
             return sema.failWithOwnedErrorMsg(msg);
@@ -3325,7 +3326,7 @@ fn zirEnsureResultNonError(sema: *Sema, block: *Block, inst: Zir.Inst.Index) Com
             const msg = msg: {
                 const msg = try sema.errMsg(block, src, "error is discarded", .{});
                 errdefer msg.destroy(sema.gpa);
-                try sema.errNote(block, src, msg, "consider using `try`, `catch`, or `if`", .{});
+                try sema.errNote(block, src, msg, "consider using 'try', 'catch', or 'if'", .{});
                 break :msg msg;
             };
             return sema.failWithOwnedErrorMsg(msg);
@@ -6874,6 +6875,8 @@ fn analyzeInlineCallArg(
                     if (err == error.AnalysisFail and param_block.comptime_reason != null) try param_block.comptime_reason.?.explain(sema, sema.err);
                     return err;
                 };
+            } else if (!is_comptime_call and zir_tags[inst] == .param_comptime) {
+                _ = try sema.resolveConstMaybeUndefVal(arg_block, arg_src, uncasted_arg, "parameter is comptime");
             }
             const casted_arg = sema.coerceExtra(arg_block, param_ty, uncasted_arg, arg_src, .{ .param_src = .{
                 .func_inst = func_inst,
@@ -6947,6 +6950,9 @@ fn analyzeInlineCallArg(
                     .val = arg_val,
                 };
             } else {
+                if (zir_tags[inst] == .param_anytype_comptime) {
+                    _ = try sema.resolveConstMaybeUndefVal(arg_block, arg_src, uncasted_arg, "parameter is comptime");
+                }
                 sema.inst_map.putAssumeCapacityNoClobber(inst, uncasted_arg);
             }
 
@@ -8467,7 +8473,7 @@ fn handleExternLibName(
             return sema.fail(
                 block,
                 src_loc,
-                "dependency on dynamic library '{s}' requires enabling Position Independent Code. Fixed by `-l{s}` or `-fPIC`.",
+                "dependency on dynamic library '{s}' requires enabling Position Independent Code. Fixed by '-l{s}' or '-fPIC'.",
                 .{ lib_name, lib_name },
             );
         }
@@ -9004,7 +9010,18 @@ fn zirParam(
         if (is_comptime and sema.preallocated_new_func != null) {
             // We have a comptime value for this parameter so it should be elided from the
             // function type of the function instruction in this block.
-            const coerced_arg = try sema.coerce(block, param_ty, arg, src);
+            const coerced_arg = sema.coerce(block, param_ty, arg, .unneeded) catch |err| switch (err) {
+                error.NeededSourceLocation => {
+                    // We are instantiating a generic function and a comptime arg
+                    // cannot be coerced to the param type, but since we don't
+                    // have the callee source location return `GenericPoison`
+                    // so that the instantiation is failed and the coercion
+                    // is handled by comptime call logic instead.
+                    assert(sema.is_generic_instantiation);
+                    return error.GenericPoison;
+                },
+                else => return err,
+            };
             sema.inst_map.putAssumeCapacity(inst, coerced_arg);
             return;
         }
@@ -19519,13 +19536,34 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
     const operand_info = operand_ty.ptrInfo().data;
     const dest_info = dest_ty.ptrInfo().data;
     if (!operand_info.mutable and dest_info.mutable) {
-        return sema.fail(block, src, "cast discards const qualifier", .{});
+        const msg = msg: {
+            const msg = try sema.errMsg(block, src, "cast discards const qualifier", .{});
+            errdefer msg.destroy(sema.gpa);
+
+            try sema.errNote(block, src, msg, "consider using '@qualCast'", .{});
+            break :msg msg;
+        };
+        return sema.failWithOwnedErrorMsg(msg);
     }
     if (operand_info.@"volatile" and !dest_info.@"volatile") {
-        return sema.fail(block, src, "cast discards volatile qualifier", .{});
+        const msg = msg: {
+            const msg = try sema.errMsg(block, src, "cast discards volatile qualifier", .{});
+            errdefer msg.destroy(sema.gpa);
+
+            try sema.errNote(block, src, msg, "consider using '@qualCast'", .{});
+            break :msg msg;
+        };
+        return sema.failWithOwnedErrorMsg(msg);
     }
     if (operand_info.@"addrspace" != dest_info.@"addrspace") {
-        return sema.fail(block, src, "cast changes pointer address space", .{});
+        const msg = msg: {
+            const msg = try sema.errMsg(block, src, "cast changes pointer address space", .{});
+            errdefer msg.destroy(sema.gpa);
+
+            try sema.errNote(block, src, msg, "consider using '@addrSpaceCast'", .{});
+            break :msg msg;
+        };
+        return sema.failWithOwnedErrorMsg(msg);
     }
 
     const dest_is_slice = dest_ty.isSlice();
@@ -19580,6 +19618,8 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
             try sema.errNote(block, dest_ty_src, msg, "'{}' has alignment '{d}'", .{
                 dest_ty.fmt(sema.mod), dest_align,
             });
+
+            try sema.errNote(block, src, msg, "consider using '@alignCast'", .{});
             break :msg msg;
         };
         return sema.failWithOwnedErrorMsg(msg);
@@ -19615,6 +19655,49 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
     return block.addBitCast(aligned_dest_ty, ptr);
 }
 
+fn zirQualCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
+    const inst_data = sema.code.instructions.items(.data)[inst].pl_node;
+    const src = inst_data.src();
+    const dest_ty_src: LazySrcLoc = .{ .node_offset_builtin_call_arg0 = inst_data.src_node };
+    const operand_src: LazySrcLoc = .{ .node_offset_builtin_call_arg1 = inst_data.src_node };
+    const extra = sema.code.extraData(Zir.Inst.Bin, inst_data.payload_index).data;
+    const dest_ty = try sema.resolveType(block, dest_ty_src, extra.lhs);
+    const operand = try sema.resolveInst(extra.rhs);
+    const operand_ty = sema.typeOf(operand);
+
+    try sema.checkPtrType(block, dest_ty_src, dest_ty);
+    try sema.checkPtrOperand(block, operand_src, operand_ty);
+
+    var operand_payload = operand_ty.ptrInfo();
+    var dest_info = dest_ty.ptrInfo();
+
+    operand_payload.data.mutable = dest_info.data.mutable;
+    operand_payload.data.@"volatile" = dest_info.data.@"volatile";
+
+    const altered_operand_ty = Type.initPayload(&operand_payload.base);
+    if (!altered_operand_ty.eql(dest_ty, sema.mod)) {
+        const msg = msg: {
+            const msg = try sema.errMsg(block, src, "'@qualCast' can only modify 'const' and 'volatile' qualifiers", .{});
+            errdefer msg.destroy(sema.gpa);
+
+            dest_info.data.mutable = !operand_ty.isConstPtr();
+            dest_info.data.@"volatile" = operand_ty.isVolatilePtr();
+            const altered_dest_ty = Type.initPayload(&dest_info.base);
+            try sema.errNote(block, src, msg, "expected type '{}'", .{altered_dest_ty.fmt(sema.mod)});
+            try sema.errNote(block, src, msg, "got type '{}'", .{operand_ty.fmt(sema.mod)});
+            break :msg msg;
+        };
+        return sema.failWithOwnedErrorMsg(msg);
+    }
+
+    if (try sema.resolveMaybeUndefVal(operand)) |operand_val| {
+        return sema.addConstant(dest_ty, operand_val);
+    }
+
+    try sema.requireRuntimeBlock(block, src, null);
+    return block.addBitCast(dest_ty, operand);
+}
+
 fn zirTruncate(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
     const inst_data = sema.code.instructions.items(.data)[inst].pl_node;
     const src = inst_data.src();
@@ -25131,7 +25214,7 @@ fn coerceExtra(
             (try sema.coerceInMemoryAllowed(block, inst_ty.errorUnionPayload(), dest_ty, false, target, dest_ty_src, inst_src)) == .ok)
         {
             try sema.errNote(block, inst_src, msg, "cannot convert error union to payload type", .{});
-            try sema.errNote(block, inst_src, msg, "consider using `try`, `catch`, or `if`", .{});
+            try sema.errNote(block, inst_src, msg, "consider using 'try', 'catch', or 'if'", .{});
         }
 
         // ?T to T
@@ -25140,7 +25223,7 @@ fn coerceExtra(
             (try sema.coerceInMemoryAllowed(block, inst_ty.optionalChild(&buf), dest_ty, false, target, dest_ty_src, inst_src)) == .ok)
         {
             try sema.errNote(block, inst_src, msg, "cannot convert optional to payload type", .{});
-            try sema.errNote(block, inst_src, msg, "consider using `.?`, `orelse`, or `if`", .{});
+            try sema.errNote(block, inst_src, msg, "consider using '.?', 'orelse', or 'if'", .{});
         }
 
         try in_memory_result.report(sema, block, inst_src, msg);
diff --git a/src/TypedValue.zig b/src/TypedValue.zig
index 6e096ee90a..cb28274f10 100644
--- a/src/TypedValue.zig
+++ b/src/TypedValue.zig
@@ -176,7 +176,9 @@ pub fn print(
 
                     var i: u32 = 0;
                     while (i < max_len) : (i += 1) {
-                        buf[i] = std.math.cast(u8, val.fieldValue(ty, i).toUnsignedInt(target)) orelse break :str;
+                        const elem = val.fieldValue(ty, i);
+                        if (elem.isUndef()) break :str;
+                        buf[i] = std.math.cast(u8, elem.toUnsignedInt(target)) orelse break :str;
                     }
 
                     const truncated = if (len > max_string_len) " (truncated)" else "";
@@ -390,6 +392,7 @@ pub fn print(
                 while (i < max_len) : (i += 1) {
                     var elem_buf: Value.ElemValueBuffer = undefined;
                     const elem_val = payload.ptr.elemValueBuffer(mod, i, &elem_buf);
+                    if (elem_val.isUndef()) break :str;
                     buf[i] = std.math.cast(u8, elem_val.toUnsignedInt(target)) orelse break :str;
                 }
 
diff --git a/src/Zir.zig b/src/Zir.zig
index 94e6a9a11a..b93422177e 100644
--- a/src/Zir.zig
+++ b/src/Zir.zig
@@ -857,6 +857,9 @@ pub const Inst = struct {
         /// Implements the `@ptrCast` builtin.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
         ptr_cast,
+        /// Implements the `@qualCast` builtin.
+        /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
+        qual_cast,
         /// Implements the `@truncate` builtin.
         /// Uses `pl_node` with payload `Bin`. `lhs` is dest type, `rhs` is operand.
         truncate,
@@ -1195,6 +1198,7 @@ pub const Inst = struct {
                 .float_cast,
                 .int_cast,
                 .ptr_cast,
+                .qual_cast,
                 .truncate,
                 .align_cast,
                 .has_field,
@@ -1484,6 +1488,7 @@ pub const Inst = struct {
                 .float_cast,
                 .int_cast,
                 .ptr_cast,
+                .qual_cast,
                 .truncate,
                 .align_cast,
                 .has_field,
@@ -1755,6 +1760,7 @@ pub const Inst = struct {
                 .float_cast = .pl_node,
                 .int_cast = .pl_node,
                 .ptr_cast = .pl_node,
+                .qual_cast = .pl_node,
                 .truncate = .pl_node,
                 .align_cast = .pl_node,
                 .typeof_builtin = .pl_node,
diff --git a/src/print_zir.zig b/src/print_zir.zig
index 6e8923bed9..e5fc8815ed 100644
--- a/src/print_zir.zig
+++ b/src/print_zir.zig
@@ -332,6 +332,7 @@ const Writer = struct {
             .float_cast,
             .int_cast,
             .ptr_cast,
+            .qual_cast,
             .truncate,
             .align_cast,
             .div_exact,