Merge pull request #20424 from mlugg/the-great-decl-split

Dismantle Decl a little bit more

9 files changed, 153 insertions, 128 deletions

diff --git a/src/Compilation.zig b/src/Compilation.zig
index de8f5542e3..b30f65ad11 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -3494,7 +3494,7 @@ fn processOneJob(comp: *Compilation, job: Job, prog_node: std.Progress.Node) !vo
                     .{@errorName(err)},
                 ));
                 decl.analysis = .codegen_failure;
-                try module.retryable_failures.append(gpa, InternPool.Depender.wrap(.{ .decl = decl_index }));
+                try module.retryable_failures.append(gpa, InternPool.AnalSubject.wrap(.{ .decl = decl_index }));
             };
         },
         .analyze_mod => |pkg| {
diff --git a/src/InternPool.zig b/src/InternPool.zig
index e297a8ea78..cf56550c25 100644
--- a/src/InternPool.zig
+++ b/src/InternPool.zig
@@ -81,7 +81,7 @@ namespace_name_deps: std.AutoArrayHashMapUnmanaged(NamespaceNameKey, DepEntry.In
 /// Given a `Depender`, points to an entry in `dep_entries` whose `depender`
 /// matches. The `next_dependee` field can be used to iterate all such entries
 /// and remove them from the corresponding lists.
-first_dependency: std.AutoArrayHashMapUnmanaged(Depender, DepEntry.Index) = .{},
+first_dependency: std.AutoArrayHashMapUnmanaged(AnalSubject, DepEntry.Index) = .{},
 
 /// Stores dependency information. The hashmaps declared above are used to look
 /// up entries in this list as required. This is not stored in `extra` so that
@@ -132,39 +132,39 @@ pub fn trackZir(ip: *InternPool, gpa: Allocator, file: *Module.File, inst: Zir.I
     return @enumFromInt(gop.index);
 }
 
-/// Reperesents the "source" of a dependency edge, i.e. either a Decl or a
-/// runtime function (represented as an InternPool index).
-/// MSB is 0 for a Decl, 1 for a function.
-pub const Depender = enum(u32) {
-    _,
+/// Analysis Subject. Represents a single entity which undergoes semantic analysis.
+/// This is either a `Decl` (in future `Cau`) or a runtime function.
+/// The LSB is used as a tag bit.
+/// This is the "source" of an incremental dependency edge.
+pub const AnalSubject = packed struct(u32) {
+    kind: enum(u1) { decl, func },
+    index: u31,
     pub const Unwrapped = union(enum) {
         decl: DeclIndex,
         func: InternPool.Index,
     };
-    pub fn unwrap(dep: Depender) Unwrapped {
-        const tag: u1 = @truncate(@intFromEnum(dep) >> 31);
-        const val: u31 = @truncate(@intFromEnum(dep));
-        return switch (tag) {
-            0 => .{ .decl = @enumFromInt(val) },
-            1 => .{ .func = @enumFromInt(val) },
+    pub fn unwrap(as: AnalSubject) Unwrapped {
+        return switch (as.kind) {
+            .decl => .{ .decl = @enumFromInt(as.index) },
+            .func => .{ .func = @enumFromInt(as.index) },
         };
     }
-    pub fn wrap(raw: Unwrapped) Depender {
-        return @enumFromInt(switch (raw) {
-            .decl => |decl| @intFromEnum(decl),
-            .func => |func| (1 << 31) | @intFromEnum(func),
-        });
+    pub fn wrap(raw: Unwrapped) AnalSubject {
+        return switch (raw) {
+            .decl => |decl| .{ .kind = .decl, .index = @intCast(@intFromEnum(decl)) },
+            .func => |func| .{ .kind = .func, .index = @intCast(@intFromEnum(func)) },
+        };
     }
-    pub fn toOptional(dep: Depender) Optional {
-        return @enumFromInt(@intFromEnum(dep));
+    pub fn toOptional(as: AnalSubject) Optional {
+        return @enumFromInt(@as(u32, @bitCast(as)));
     }
     pub const Optional = enum(u32) {
         none = std.math.maxInt(u32),
         _,
-        pub fn unwrap(opt: Optional) ?Depender {
+        pub fn unwrap(opt: Optional) ?AnalSubject {
             return switch (opt) {
                 .none => null,
-                _ => @enumFromInt(@intFromEnum(opt)),
+                _ => @bitCast(@intFromEnum(opt)),
             };
         }
     };
@@ -178,7 +178,7 @@ pub const Dependee = union(enum) {
     namespace_name: NamespaceNameKey,
 };
 
-pub fn removeDependenciesForDepender(ip: *InternPool, gpa: Allocator, depender: Depender) void {
+pub fn removeDependenciesForDepender(ip: *InternPool, gpa: Allocator, depender: AnalSubject) void {
     var opt_idx = (ip.first_dependency.fetchSwapRemove(depender) orelse return).value.toOptional();
 
     while (opt_idx.unwrap()) |idx| {
@@ -207,7 +207,7 @@ pub fn removeDependenciesForDepender(ip: *InternPool, gpa: Allocator, depender:
 pub const DependencyIterator = struct {
     ip: *const InternPool,
     next_entry: DepEntry.Index.Optional,
-    pub fn next(it: *DependencyIterator) ?Depender {
+    pub fn next(it: *DependencyIterator) ?AnalSubject {
         const idx = it.next_entry.unwrap() orelse return null;
         const entry = it.ip.dep_entries.items[@intFromEnum(idx)];
         it.next_entry = entry.next;
@@ -236,7 +236,7 @@ pub fn dependencyIterator(ip: *const InternPool, dependee: Dependee) DependencyI
     };
 }
 
-pub fn addDependency(ip: *InternPool, gpa: Allocator, depender: Depender, dependee: Dependee) Allocator.Error!void {
+pub fn addDependency(ip: *InternPool, gpa: Allocator, depender: AnalSubject, dependee: Dependee) Allocator.Error!void {
     const first_depender_dep: DepEntry.Index.Optional = if (ip.first_dependency.get(depender)) |idx| dep: {
         // The entry already exists, so there is capacity to overwrite it later.
         break :dep idx.toOptional();
@@ -300,7 +300,7 @@ pub const DepEntry = extern struct {
     /// the first and only entry in one of `intern_pool.*_deps`, and does not
     /// appear in any list by `first_dependency`, but is not in
     /// `free_dep_entries` since `*_deps` stores a reference to it.
-    depender: Depender.Optional,
+    depender: AnalSubject.Optional,
     /// Index into `dep_entries` forming a doubly linked list of all dependencies on this dependee.
     /// Used to iterate all dependers for a given dependee during an update.
     /// null if this is the end of the list.
@@ -6958,7 +6958,6 @@ fn finishFuncInstance(
     const decl_index = try ip.createDecl(gpa, .{
         .name = undefined,
         .src_namespace = fn_owner_decl.src_namespace,
-        .src_line = fn_owner_decl.src_line,
         .has_tv = true,
         .owns_tv = true,
         .val = @import("Value.zig").fromInterned(func_index),
diff --git a/src/Sema.zig b/src/Sema.zig
index a59768686b..db520f5789 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -2735,12 +2735,12 @@ fn maybeRemoveOutdatedType(sema: *Sema, ty: InternPool.Index) !bool {
     if (!zcu.comp.debug_incremental) return false;
 
     const decl_index = Type.fromInterned(ty).getOwnerDecl(zcu);
-    const decl_as_depender = InternPool.Depender.wrap(.{ .decl = decl_index });
+    const decl_as_depender = InternPool.AnalSubject.wrap(.{ .decl = decl_index });
     const was_outdated = zcu.outdated.swapRemove(decl_as_depender) or
         zcu.potentially_outdated.swapRemove(decl_as_depender);
     if (!was_outdated) return false;
     _ = zcu.outdated_ready.swapRemove(decl_as_depender);
-    zcu.intern_pool.removeDependenciesForDepender(zcu.gpa, InternPool.Depender.wrap(.{ .decl = decl_index }));
+    zcu.intern_pool.removeDependenciesForDepender(zcu.gpa, InternPool.AnalSubject.wrap(.{ .decl = decl_index }));
     zcu.intern_pool.remove(ty);
     zcu.declPtr(decl_index).analysis = .dependency_failure;
     try zcu.markDependeeOutdated(.{ .decl_val = decl_index });
@@ -2827,7 +2827,6 @@ fn zirStructDecl(
         small.name_strategy,
         "struct",
         inst,
-        extra.data.src_line,
     );
     mod.declPtr(new_decl_index).owns_tv = true;
     errdefer mod.abortAnonDecl(new_decl_index);
@@ -2835,7 +2834,7 @@ fn zirStructDecl(
     if (sema.mod.comp.debug_incremental) {
         try ip.addDependency(
             sema.gpa,
-            InternPool.Depender.wrap(.{ .decl = new_decl_index }),
+            InternPool.AnalSubject.wrap(.{ .decl = new_decl_index }),
             .{ .src_hash = try ip.trackZir(sema.gpa, block.getFileScope(mod), inst) },
         );
     }
@@ -2864,7 +2863,6 @@ fn createAnonymousDeclTypeNamed(
     name_strategy: Zir.Inst.NameStrategy,
     anon_prefix: []const u8,
     inst: ?Zir.Inst.Index,
-    src_line: u32,
 ) !InternPool.DeclIndex {
     const zcu = sema.mod;
     const ip = &zcu.intern_pool;
@@ -2876,7 +2874,7 @@ fn createAnonymousDeclTypeNamed(
     switch (name_strategy) {
         .anon => {}, // handled after switch
         .parent => {
-            try zcu.initNewAnonDecl(new_decl_index, src_line, val, block.type_name_ctx);
+            try zcu.initNewAnonDecl(new_decl_index, val, block.type_name_ctx);
             return new_decl_index;
         },
         .func => func_strat: {
@@ -2921,7 +2919,7 @@ fn createAnonymousDeclTypeNamed(
 
             try writer.writeByte(')');
             const name = try ip.getOrPutString(gpa, buf.items, .no_embedded_nulls);
-            try zcu.initNewAnonDecl(new_decl_index, src_line, val, name);
+            try zcu.initNewAnonDecl(new_decl_index, val, name);
             return new_decl_index;
         },
         .dbg_var => {
@@ -2935,7 +2933,7 @@ fn createAnonymousDeclTypeNamed(
                     const name = try ip.getOrPutStringFmt(gpa, "{}.{s}", .{
                         block.type_name_ctx.fmt(ip), zir_data[i].str_op.getStr(sema.code),
                     }, .no_embedded_nulls);
-                    try zcu.initNewAnonDecl(new_decl_index, src_line, val, name);
+                    try zcu.initNewAnonDecl(new_decl_index, val, name);
                     return new_decl_index;
                 },
                 else => {},
@@ -2956,7 +2954,7 @@ fn createAnonymousDeclTypeNamed(
     const name = ip.getOrPutStringFmt(gpa, "{}__{s}_{d}", .{
         block.type_name_ctx.fmt(ip), anon_prefix, @intFromEnum(new_decl_index),
     }, .no_embedded_nulls) catch unreachable;
-    try zcu.initNewAnonDecl(new_decl_index, src_line, val, name);
+    try zcu.initNewAnonDecl(new_decl_index, val, name);
     return new_decl_index;
 }
 
@@ -3062,7 +3060,6 @@ fn zirEnumDecl(
         small.name_strategy,
         "enum",
         inst,
-        extra.data.src_line,
     );
     const new_decl = mod.declPtr(new_decl_index);
     new_decl.owns_tv = true;
@@ -3071,7 +3068,7 @@ fn zirEnumDecl(
     if (sema.mod.comp.debug_incremental) {
         try mod.intern_pool.addDependency(
             sema.gpa,
-            InternPool.Depender.wrap(.{ .decl = new_decl_index }),
+            InternPool.AnalSubject.wrap(.{ .decl = new_decl_index }),
             .{ .src_hash = try mod.intern_pool.trackZir(sema.gpa, block.getFileScope(mod), inst) },
         );
     }
@@ -3330,7 +3327,6 @@ fn zirUnionDecl(
         small.name_strategy,
         "union",
         inst,
-        extra.data.src_line,
     );
     mod.declPtr(new_decl_index).owns_tv = true;
     errdefer mod.abortAnonDecl(new_decl_index);
@@ -3338,7 +3334,7 @@ fn zirUnionDecl(
     if (sema.mod.comp.debug_incremental) {
         try mod.intern_pool.addDependency(
             sema.gpa,
-            InternPool.Depender.wrap(.{ .decl = new_decl_index }),
+            InternPool.AnalSubject.wrap(.{ .decl = new_decl_index }),
             .{ .src_hash = try mod.intern_pool.trackZir(sema.gpa, block.getFileScope(mod), inst) },
         );
     }
@@ -3419,7 +3415,6 @@ fn zirOpaqueDecl(
         small.name_strategy,
         "opaque",
         inst,
-        extra.data.src_line,
     );
     mod.declPtr(new_decl_index).owns_tv = true;
     errdefer mod.abortAnonDecl(new_decl_index);
@@ -3427,7 +3422,7 @@ fn zirOpaqueDecl(
     if (sema.mod.comp.debug_incremental) {
         try ip.addDependency(
             gpa,
-            InternPool.Depender.wrap(.{ .decl = new_decl_index }),
+            InternPool.AnalSubject.wrap(.{ .decl = new_decl_index }),
             .{ .src_hash = try ip.trackZir(gpa, block.getFileScope(mod), inst) },
         );
     }
@@ -21546,7 +21541,7 @@ fn zirReify(
                 .needed_comptime_reason = "struct fields must be comptime-known",
             });
 
-            return try sema.reifyStruct(block, inst, src, layout, backing_integer_val, fields_arr, name_strategy, is_tuple_val.toBool(), extra.src_line);
+            return try sema.reifyStruct(block, inst, src, layout, backing_integer_val, fields_arr, name_strategy, is_tuple_val.toBool());
         },
         .Enum => {
             const struct_type = ip.loadStructType(ip.typeOf(union_val.val));
@@ -21575,7 +21570,7 @@ fn zirReify(
                 .needed_comptime_reason = "enum fields must be comptime-known",
             });
 
-            return sema.reifyEnum(block, inst, src, tag_type_val.toType(), is_exhaustive_val.toBool(), fields_arr, name_strategy, extra.src_line);
+            return sema.reifyEnum(block, inst, src, tag_type_val.toType(), is_exhaustive_val.toBool(), fields_arr, name_strategy);
         },
         .Opaque => {
             const struct_type = ip.loadStructType(ip.typeOf(union_val.val));
@@ -21606,7 +21601,6 @@ fn zirReify(
                 name_strategy,
                 "opaque",
                 inst,
-                extra.src_line,
             );
             mod.declPtr(new_decl_index).owns_tv = true;
             errdefer mod.abortAnonDecl(new_decl_index);
@@ -21643,7 +21637,7 @@ fn zirReify(
                 .needed_comptime_reason = "union fields must be comptime-known",
             });
 
-            return sema.reifyUnion(block, inst, src, layout, tag_type_val, fields_arr, name_strategy, extra.src_line);
+            return sema.reifyUnion(block, inst, src, layout, tag_type_val, fields_arr, name_strategy);
         },
         .Fn => {
             const struct_type = ip.loadStructType(ip.typeOf(union_val.val));
@@ -21745,7 +21739,6 @@ fn reifyEnum(
     is_exhaustive: bool,
     fields_val: Value,
     name_strategy: Zir.Inst.NameStrategy,
-    src_line: u32,
 ) CompileError!Air.Inst.Ref {
     const mod = sema.mod;
     const gpa = sema.gpa;
@@ -21807,7 +21800,6 @@ fn reifyEnum(
         name_strategy,
         "enum",
         inst,
-        src_line,
     );
     mod.declPtr(new_decl_index).owns_tv = true;
     errdefer mod.abortAnonDecl(new_decl_index);
@@ -21871,7 +21863,6 @@ fn reifyUnion(
     opt_tag_type_val: Value,
     fields_val: Value,
     name_strategy: Zir.Inst.NameStrategy,
-    src_line: u32,
 ) CompileError!Air.Inst.Ref {
     const mod = sema.mod;
     const gpa = sema.gpa;
@@ -21955,7 +21946,6 @@ fn reifyUnion(
         name_strategy,
         "union",
         inst,
-        src_line,
     );
     mod.declPtr(new_decl_index).owns_tv = true;
     errdefer mod.abortAnonDecl(new_decl_index);
@@ -22051,7 +22041,7 @@ fn reifyUnion(
             }
         }
 
-        const enum_tag_ty = try sema.generateUnionTagTypeSimple(block, field_names.keys(), mod.declPtr(new_decl_index), src_line);
+        const enum_tag_ty = try sema.generateUnionTagTypeSimple(block, field_names.keys(), mod.declPtr(new_decl_index));
         break :tag_ty .{ enum_tag_ty, false };
     };
     errdefer if (!has_explicit_tag) ip.remove(enum_tag_ty); // remove generated tag type on error
@@ -22112,7 +22102,6 @@ fn reifyStruct(
     fields_val: Value,
     name_strategy: Zir.Inst.NameStrategy,
     is_tuple: bool,
-    src_line: u32,
 ) CompileError!Air.Inst.Ref {
     const mod = sema.mod;
     const gpa = sema.gpa;
@@ -22213,7 +22202,6 @@ fn reifyStruct(
         name_strategy,
         "struct",
         inst,
-        src_line,
     );
     mod.declPtr(new_decl_index).owns_tv = true;
     errdefer mod.abortAnonDecl(new_decl_index);
@@ -26347,7 +26335,6 @@ fn zirBuiltinExtern(
     const new_decl = mod.declPtr(new_decl_index);
     try mod.initNewAnonDecl(
         new_decl_index,
-        sema.owner_decl.src_line,
         Value.fromInterned(
             if (Type.fromInterned(ptr_info.child).zigTypeTag(mod) == .Fn)
                 try ip.getExternFunc(sema.gpa, .{
@@ -36745,10 +36732,10 @@ fn semaUnionFields(mod: *Module, arena: Allocator, union_type: InternPool.Loaded
             return sema.failWithOwnedErrorMsg(&block_scope, msg);
         }
     } else if (enum_field_vals.count() > 0) {
-        const enum_ty = try sema.generateUnionTagTypeNumbered(&block_scope, enum_field_names, enum_field_vals.keys(), mod.declPtr(union_type.decl), extra.data.src_line);
+        const enum_ty = try sema.generateUnionTagTypeNumbered(&block_scope, enum_field_names, enum_field_vals.keys(), mod.declPtr(union_type.decl));
         union_type.tagTypePtr(ip).* = enum_ty;
     } else {
-        const enum_ty = try sema.generateUnionTagTypeSimple(&block_scope, enum_field_names, mod.declPtr(union_type.decl), extra.data.src_line);
+        const enum_ty = try sema.generateUnionTagTypeSimple(&block_scope, enum_field_names, mod.declPtr(union_type.decl));
         union_type.tagTypePtr(ip).* = enum_ty;
     }
 }
@@ -36766,7 +36753,6 @@ fn generateUnionTagTypeNumbered(
     enum_field_names: []const InternPool.NullTerminatedString,
     enum_field_vals: []const InternPool.Index,
     union_owner_decl: *Module.Decl,
-    src_line: u32,
 ) !InternPool.Index {
     const mod = sema.mod;
     const gpa = sema.gpa;
@@ -36783,7 +36769,6 @@ fn generateUnionTagTypeNumbered(
     );
     try mod.initNewAnonDecl(
         new_decl_index,
-        src_line,
         Value.@"unreachable",
         name,
     );
@@ -36816,7 +36801,6 @@ fn generateUnionTagTypeSimple(
     block: *Block,
     enum_field_names: []const InternPool.NullTerminatedString,
     union_owner_decl: *Module.Decl,
-    src_line: u32,
 ) !InternPool.Index {
     const mod = sema.mod;
     const ip = &mod.intern_pool;
@@ -36834,7 +36818,6 @@ fn generateUnionTagTypeSimple(
         );
         try mod.initNewAnonDecl(
             new_decl_index,
-            src_line,
             Value.@"unreachable",
             name,
         );
@@ -38379,7 +38362,7 @@ pub fn declareDependency(sema: *Sema, dependee: InternPool.Dependee) !void {
         return;
     }
 
-    const depender = InternPool.Depender.wrap(
+    const depender = InternPool.AnalSubject.wrap(
         if (sema.owner_func_index != .none)
             .{ .func = sema.owner_func_index }
         else
diff --git a/src/Zcu.zig b/src/Zcu.zig
index 3faa1b8780..a490990cf3 100644
--- a/src/Zcu.zig
+++ b/src/Zcu.zig
@@ -139,26 +139,26 @@ global_error_set: GlobalErrorSet = .{},
 /// Maximum amount of distinct error values, set by --error-limit
 error_limit: ErrorInt,
 
-/// Value is the number of PO or outdated Decls which this Depender depends on.
-potentially_outdated: std.AutoArrayHashMapUnmanaged(InternPool.Depender, u32) = .{},
-/// Value is the number of PO or outdated Decls which this Depender depends on.
-/// Once this value drops to 0, the Depender is a candidate for re-analysis.
-outdated: std.AutoArrayHashMapUnmanaged(InternPool.Depender, u32) = .{},
-/// This contains all `Depender`s in `outdated` whose PO dependency count is 0.
-/// Such `Depender`s are ready for immediate re-analysis.
+/// Value is the number of PO or outdated Decls which this AnalSubject depends on.
+potentially_outdated: std.AutoArrayHashMapUnmanaged(InternPool.AnalSubject, u32) = .{},
+/// Value is the number of PO or outdated Decls which this AnalSubject depends on.
+/// Once this value drops to 0, the AnalSubject is a candidate for re-analysis.
+outdated: std.AutoArrayHashMapUnmanaged(InternPool.AnalSubject, u32) = .{},
+/// This contains all `AnalSubject`s in `outdated` whose PO dependency count is 0.
+/// Such `AnalSubject`s are ready for immediate re-analysis.
 /// See `findOutdatedToAnalyze` for details.
-outdated_ready: std.AutoArrayHashMapUnmanaged(InternPool.Depender, void) = .{},
+outdated_ready: std.AutoArrayHashMapUnmanaged(InternPool.AnalSubject, void) = .{},
 /// This contains a set of Decls which may not be in `outdated`, but are the
 /// root Decls of files which have updated source and thus must be re-analyzed.
 /// If such a Decl is only in this set, the struct type index may be preserved
 /// (only the namespace might change). If such a Decl is also `outdated`, the
 /// struct type index must be recreated.
 outdated_file_root: std.AutoArrayHashMapUnmanaged(Decl.Index, void) = .{},
-/// This contains a list of Dependers whose analysis or codegen failed, but the
+/// This contains a list of AnalSubject whose analysis or codegen failed, but the
 /// failure was something like running out of disk space, and trying again may
 /// succeed. On the next update, we will flush this list, marking all members of
 /// it as outdated.
-retryable_failures: std.ArrayListUnmanaged(InternPool.Depender) = .{},
+retryable_failures: std.ArrayListUnmanaged(InternPool.AnalSubject) = .{},
 
 stage1_flags: packed struct {
     have_winmain: bool = false,
@@ -347,10 +347,6 @@ pub const Decl = struct {
     /// there is no parent.
     src_namespace: Namespace.Index,
 
-    /// Line number corresponding to `src_node`. Stored separately so that source files
-    /// do not need to be loaded into memory in order to compute debug line numbers.
-    /// This value is absolute.
-    src_line: u32,
     /// Index of the ZIR `declaration` instruction from which this `Decl` was created.
     /// For the root `Decl` of a `File` and legacy anonymous decls, this is `.none`.
     zir_decl_index: InternPool.TrackedInst.Index.Optional,
@@ -564,6 +560,33 @@ pub const Decl = struct {
             .offset = LazySrcLoc.Offset.nodeOffset(0),
         };
     }
+
+    pub fn navSrcLine(decl: Decl, zcu: *Zcu) u32 {
+        const tracked = decl.zir_decl_index.unwrap() orelse inst: {
+            // generic instantiation
+            assert(decl.has_tv);
+            assert(decl.owns_tv);
+            const generic_owner_func = switch (zcu.intern_pool.indexToKey(decl.val.toIntern())) {
+                .func => |func| func.generic_owner,
+                else => return 0, // TODO: this is probably a `variable` or something; figure this out when we finish sorting out `Decl`.
+            };
+            const generic_owner_decl = zcu.declPtr(zcu.funcInfo(generic_owner_func).owner_decl);
+            break :inst generic_owner_decl.zir_decl_index.unwrap().?;
+        };
+        const info = tracked.resolveFull(&zcu.intern_pool);
+        const file = zcu.import_table.values()[zcu.path_digest_map.getIndex(info.path_digest).?];
+        assert(file.zir_loaded);
+        const zir = file.zir;
+        const inst = zir.instructions.get(@intFromEnum(info.inst));
+        assert(inst.tag == .declaration);
+        return zir.extraData(Zir.Inst.Declaration, inst.data.declaration.payload_index).data.src_line;
+    }
+
+    pub fn typeSrcLine(decl: Decl, zcu: *Zcu) u32 {
+        assert(decl.has_tv);
+        assert(decl.owns_tv);
+        return decl.val.toType().typeDeclSrcLine(zcu).?;
+    }
 };
 
 /// This state is attached to every Decl when Module emit_h is non-null.
@@ -3114,9 +3137,9 @@ fn markPoDependeeUpToDate(zcu: *Zcu, dependee: InternPool.Dependee) !void {
     }
 }
 
-/// Given a Depender which is newly outdated or PO, mark all Dependers which may
-/// in turn be PO, due to a dependency on the original Depender's tyval or IES.
-fn markTransitiveDependersPotentiallyOutdated(zcu: *Zcu, maybe_outdated: InternPool.Depender) !void {
+/// Given a AnalSubject which is newly outdated or PO, mark all AnalSubjects which may
+/// in turn be PO, due to a dependency on the original AnalSubject's tyval or IES.
+fn markTransitiveDependersPotentiallyOutdated(zcu: *Zcu, maybe_outdated: InternPool.AnalSubject) !void {
     var it = zcu.intern_pool.dependencyIterator(switch (maybe_outdated.unwrap()) {
         .decl => |decl_index| .{ .decl_val = decl_index }, // TODO: also `decl_ref` deps when introduced
         .func => |func_index| .{ .func_ies = func_index },
@@ -3138,12 +3161,12 @@ fn markTransitiveDependersPotentiallyOutdated(zcu: *Zcu, maybe_outdated: InternP
             continue;
         }
         try zcu.potentially_outdated.putNoClobber(zcu.gpa, po, 1);
-        // This Depender was not already PO, so we must recursively mark its dependers as also PO.
+        // This AnalSubject was not already PO, so we must recursively mark its dependers as also PO.
         try zcu.markTransitiveDependersPotentiallyOutdated(po);
     }
 }
 
-pub fn findOutdatedToAnalyze(zcu: *Zcu) Allocator.Error!?InternPool.Depender {
+pub fn findOutdatedToAnalyze(zcu: *Zcu) Allocator.Error!?InternPool.AnalSubject {
     if (!zcu.comp.debug_incremental) return null;
 
     if (zcu.outdated.count() == 0 and zcu.potentially_outdated.count() == 0) {
@@ -3151,8 +3174,8 @@ pub fn findOutdatedToAnalyze(zcu: *Zcu) Allocator.Error!?InternPool.Depender {
         return null;
     }
 
-    // Our goal is to find an outdated Depender which itself has no outdated or
-    // PO dependencies. Most of the time, such a Depender will exist - we track
+    // Our goal is to find an outdated AnalSubject which itself has no outdated or
+    // PO dependencies. Most of the time, such an AnalSubject will exist - we track
     // them in the `outdated_ready` set for efficiency. However, this is not
     // necessarily the case, since the Decl dependency graph may contain loops
     // via mutually recursive definitions:
@@ -3174,7 +3197,7 @@ pub fn findOutdatedToAnalyze(zcu: *Zcu) Allocator.Error!?InternPool.Depender {
     // `outdated`. This set will be small (number of files changed in this
     // update), so it's alright for us to just iterate here.
     for (zcu.outdated_file_root.keys()) |file_decl| {
-        const decl_depender = InternPool.Depender.wrap(.{ .decl = file_decl });
+        const decl_depender = InternPool.AnalSubject.wrap(.{ .decl = file_decl });
         if (zcu.outdated.contains(decl_depender)) {
             // Since we didn't hit this in the first loop, this Decl must have
             // pending dependencies, so is ineligible.
@@ -3190,7 +3213,7 @@ pub fn findOutdatedToAnalyze(zcu: *Zcu) Allocator.Error!?InternPool.Depender {
         return decl_depender;
     }
 
-    // There is no single Depender which is ready for re-analysis. Instead, we
+    // There is no single AnalSubject which is ready for re-analysis. Instead, we
     // must assume that some Decl with PO dependencies is outdated - e.g. in the
     // above example we arbitrarily pick one of A or B. We should select a Decl,
     // since a Decl is definitely responsible for the loop in the dependency
@@ -3198,7 +3221,7 @@ pub fn findOutdatedToAnalyze(zcu: *Zcu) Allocator.Error!?InternPool.Depender {
 
     // The choice of this Decl could have a big impact on how much total
     // analysis we perform, since if analysis concludes its tyval is unchanged,
-    // then other PO Dependers may be resolved as up-to-date. To hopefully avoid
+    // then other PO AnalSubject may be resolved as up-to-date. To hopefully avoid
     // doing too much work, let's find a Decl which the most things depend on -
     // the idea is that this will resolve a lot of loops (but this is only a
     // heuristic).
@@ -3248,7 +3271,7 @@ pub fn findOutdatedToAnalyze(zcu: *Zcu) Allocator.Error!?InternPool.Depender {
         chosen_decl_dependers,
     });
 
-    return InternPool.Depender.wrap(.{ .decl = chosen_decl_idx.? });
+    return InternPool.AnalSubject.wrap(.{ .decl = chosen_decl_idx.? });
 }
 
 /// During an incremental update, before semantic analysis, call this to flush all values from
@@ -3258,12 +3281,12 @@ pub fn flushRetryableFailures(zcu: *Zcu) !void {
     for (zcu.retryable_failures.items) |depender| {
         if (zcu.outdated.contains(depender)) continue;
         if (zcu.potentially_outdated.fetchSwapRemove(depender)) |kv| {
-            // This Depender was already PO, but we now consider it outdated.
+            // This AnalSubject was already PO, but we now consider it outdated.
             // Any transitive dependencies are already marked PO.
             try zcu.outdated.put(gpa, depender, kv.value);
             continue;
         }
-        // This Depender was not marked PO, but is now outdated. Mark it as
+        // This AnalSubject was not marked PO, but is now outdated. Mark it as
         // such, then recursively mark transitive dependencies as PO.
         try zcu.outdated.put(gpa, depender, 0);
         try zcu.markTransitiveDependersPotentiallyOutdated(depender);
@@ -3433,7 +3456,7 @@ pub fn ensureDeclAnalyzed(mod: *Module, decl_index: Decl.Index) SemaError!void {
     // which tries to limit re-analysis to Decls whose previously listed
     // dependencies are all up-to-date.
 
-    const decl_as_depender = InternPool.Depender.wrap(.{ .decl = decl_index });
+    const decl_as_depender = InternPool.AnalSubject.wrap(.{ .decl = decl_index });
     const decl_was_outdated = mod.outdated.swapRemove(decl_as_depender) or
         mod.potentially_outdated.swapRemove(decl_as_depender);
 
@@ -3499,7 +3522,7 @@ pub fn ensureDeclAnalyzed(mod: *Module, decl_index: Decl.Index) SemaError!void {
             else => |e| {
                 decl.analysis = .sema_failure;
                 try mod.failed_decls.ensureUnusedCapacity(mod.gpa, 1);
-                try mod.retryable_failures.append(mod.gpa, InternPool.Depender.wrap(.{ .decl = decl_index }));
+                try mod.retryable_failures.append(mod.gpa, InternPool.AnalSubject.wrap(.{ .decl = decl_index }));
                 mod.failed_decls.putAssumeCapacityNoClobber(decl_index, try ErrorMsg.create(
                     mod.gpa,
                     decl.navSrcLoc(mod).upgrade(mod),
@@ -3558,7 +3581,7 @@ pub fn ensureFuncBodyAnalyzed(zcu: *Zcu, maybe_coerced_func_index: InternPool.In
     // that's the case, we should remove this function from the binary.
     if (decl.val.ip_index != func_index) {
         try zcu.markDependeeOutdated(.{ .func_ies = func_index });
-        ip.removeDependenciesForDepender(gpa, InternPool.Depender.wrap(.{ .func = func_index }));
+        ip.removeDependenciesForDepender(gpa, InternPool.AnalSubject.wrap(.{ .func = func_index }));
         ip.remove(func_index);
         @panic("TODO: remove orphaned function from binary");
     }
@@ -3584,7 +3607,7 @@ pub fn ensureFuncBodyAnalyzed(zcu: *Zcu, maybe_coerced_func_index: InternPool.In
         .complete => {},
     }
 
-    const func_as_depender = InternPool.Depender.wrap(.{ .func = func_index });
+    const func_as_depender = InternPool.AnalSubject.wrap(.{ .func = func_index });
     const was_outdated = zcu.outdated.swapRemove(func_as_depender) or
         zcu.potentially_outdated.swapRemove(func_as_depender);
 
@@ -3705,7 +3728,7 @@ pub fn ensureFuncBodyAnalyzed(zcu: *Zcu, maybe_coerced_func_index: InternPool.In
                     .{@errorName(err)},
                 ));
                 func.analysis(ip).state = .codegen_failure;
-                try zcu.retryable_failures.append(zcu.gpa, InternPool.Depender.wrap(.{ .func = func_index }));
+                try zcu.retryable_failures.append(zcu.gpa, InternPool.AnalSubject.wrap(.{ .func = func_index }));
             },
         };
     } else if (zcu.llvm_object) |llvm_object| {
@@ -3750,7 +3773,7 @@ pub fn ensureFuncBodyAnalysisQueued(mod: *Module, func_index: InternPool.Index)
 
     assert(decl.has_tv);
 
-    const func_as_depender = InternPool.Depender.wrap(.{ .func = func_index });
+    const func_as_depender = InternPool.AnalSubject.wrap(.{ .func = func_index });
     const is_outdated = mod.outdated.contains(func_as_depender) or
         mod.potentially_outdated.contains(func_as_depender);
 
@@ -3834,7 +3857,7 @@ fn getFileRootStruct(zcu: *Zcu, decl_index: Decl.Index, namespace_index: Namespa
     if (zcu.comp.debug_incremental) {
         try ip.addDependency(
             gpa,
-            InternPool.Depender.wrap(.{ .decl = decl_index }),
+            InternPool.AnalSubject.wrap(.{ .decl = decl_index }),
             .{ .src_hash = tracked_inst },
         );
     }
@@ -3883,7 +3906,7 @@ fn semaFileUpdate(zcu: *Zcu, file: *File, type_outdated: bool) SemaError!bool {
 
     if (type_outdated) {
         // Invalidate the existing type, reusing the decl and namespace.
-        zcu.intern_pool.removeDependenciesForDepender(zcu.gpa, InternPool.Depender.wrap(.{ .decl = file.root_decl.unwrap().? }));
+        zcu.intern_pool.removeDependenciesForDepender(zcu.gpa, InternPool.AnalSubject.wrap(.{ .decl = file.root_decl.unwrap().? }));
         zcu.intern_pool.remove(decl.val.toIntern());
         decl.val = undefined;
         _ = try zcu.getFileRootStruct(file.root_decl.unwrap().?, decl.src_namespace, file);
@@ -3944,7 +3967,6 @@ fn semaFile(mod: *Module, file: *File) SemaError!void {
 
     new_decl.name = try file.fullyQualifiedName(mod);
     new_decl.name_fully_qualified = true;
-    new_decl.src_line = 0;
     new_decl.is_pub = true;
     new_decl.is_exported = false;
     new_decl.alignment = .none;
@@ -4075,7 +4097,7 @@ fn semaDecl(mod: *Module, decl_index: Decl.Index) !SemaDeclResult {
         break :ip_index .none;
     };
 
-    mod.intern_pool.removeDependenciesForDepender(gpa, InternPool.Depender.wrap(.{ .decl = decl_index }));
+    mod.intern_pool.removeDependenciesForDepender(gpa, InternPool.AnalSubject.wrap(.{ .decl = decl_index }));
 
     decl.analysis = .in_progress;
 
@@ -4301,7 +4323,7 @@ fn semaAnonOwnerDecl(zcu: *Zcu, decl_index: Decl.Index) !SemaDeclResult {
     // with a new Decl.
     //
     // Yes, this does mean that any type owner Decl has a constant value for its entire lifetime.
-    zcu.intern_pool.removeDependenciesForDepender(zcu.gpa, InternPool.Depender.wrap(.{ .decl = decl_index }));
+    zcu.intern_pool.removeDependenciesForDepender(zcu.gpa, InternPool.AnalSubject.wrap(.{ .decl = decl_index }));
     zcu.intern_pool.remove(decl.val.toIntern());
     decl.analysis = .dependency_failure;
     return .{
@@ -4762,8 +4784,6 @@ fn scanDecl(iter: *ScanDeclIter, decl_inst: Zir.Inst.Index) Allocator.Error!void
     const extra = zir.extraData(Zir.Inst.Declaration, inst_data.payload_index);
     const declaration = extra.data;
 
-    const line = iter.parent_decl.src_line + declaration.line_offset;
-
     // Every Decl needs a name.
     const decl_name: InternPool.NullTerminatedString, const kind: Decl.Kind, const is_named_test: bool = switch (declaration.name) {
         .@"comptime" => info: {
@@ -4850,7 +4870,6 @@ fn scanDecl(iter: *ScanDeclIter, decl_inst: Zir.Inst.Index) Allocator.Error!void
         const was_exported = decl.is_exported;
         assert(decl.kind == kind); // ZIR tracking should preserve this
         decl.name = decl_name;
-        decl.src_line = line;
         decl.is_pub = declaration.flags.is_pub;
         decl.is_exported = declaration.flags.is_export;
         break :decl_index .{ was_exported, decl_index };
@@ -4860,7 +4879,6 @@ fn scanDecl(iter: *ScanDeclIter, decl_inst: Zir.Inst.Index) Allocator.Error!void
         const new_decl = zcu.declPtr(new_decl_index);
         new_decl.kind = kind;
         new_decl.name = decl_name;
-        new_decl.src_line = line;
         new_decl.is_pub = declaration.flags.is_pub;
         new_decl.is_exported = declaration.flags.is_export;
         new_decl.zir_decl_index = tracked_inst.toOptional();
@@ -5008,7 +5026,7 @@ pub fn analyzeFnBody(mod: *Module, func_index: InternPool.Index, arena: Allocato
     const decl_prog_node = mod.sema_prog_node.start((try decl.fullyQualifiedName(mod)).toSlice(ip), 0);
     defer decl_prog_node.end();
 
-    mod.intern_pool.removeDependenciesForDepender(gpa, InternPool.Depender.wrap(.{ .func = func_index }));
+    mod.intern_pool.removeDependenciesForDepender(gpa, InternPool.AnalSubject.wrap(.{ .func = func_index }));
 
     var comptime_err_ret_trace = std.ArrayList(LazySrcLoc).init(gpa);
     defer comptime_err_ret_trace.deinit();
@@ -5263,7 +5281,6 @@ pub fn allocateNewDecl(zcu: *Zcu, namespace: Namespace.Index) !Decl.Index {
     const decl_index = try zcu.intern_pool.createDecl(gpa, .{
         .name = undefined,
         .src_namespace = namespace,
-        .src_line = undefined,
         .has_tv = false,
         .owns_tv = false,
         .val = undefined,
@@ -5311,14 +5328,12 @@ pub fn errorSetBits(mod: *Module) u16 {
 pub fn initNewAnonDecl(
     mod: *Module,
     new_decl_index: Decl.Index,
-    src_line: u32,
     val: Value,
     name: InternPool.NullTerminatedString,
 ) Allocator.Error!void {
     const new_decl = mod.declPtr(new_decl_index);
 
     new_decl.name = name;
-    new_decl.src_line = src_line;
     new_decl.val = val;
     new_decl.alignment = .none;
     new_decl.@"linksection" = .none;
@@ -5612,7 +5627,7 @@ pub fn linkerUpdateDecl(zcu: *Zcu, decl_index: Decl.Index) !void {
                     .{@errorName(err)},
                 ));
                 decl.analysis = .codegen_failure;
-                try zcu.retryable_failures.append(zcu.gpa, InternPool.Depender.wrap(.{ .decl = decl_index }));
+                try zcu.retryable_failures.append(zcu.gpa, InternPool.AnalSubject.wrap(.{ .decl = decl_index }));
             },
         };
     } else if (zcu.llvm_object) |llvm_object| {
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 1e29d2cbe5..00cfd4404a 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -1697,7 +1697,7 @@ pub const Object = struct {
         const file, const subprogram = if (!wip.strip) debug_info: {
             const file = try o.getDebugFile(namespace.file_scope);
 
-            const line_number = decl.src_line + 1;
+            const line_number = decl.navSrcLine(zcu) + 1;
             const is_internal_linkage = decl.val.getExternFunc(zcu) == null and
                 !zcu.decl_exports.contains(decl_index);
             const debug_decl_type = try o.lowerDebugType(decl.typeOf(zcu));
@@ -1741,7 +1741,7 @@ pub const Object = struct {
             .sync_scope = if (owner_mod.single_threaded) .singlethread else .system,
             .file = file,
             .scope = subprogram,
-            .base_line = dg.decl.src_line,
+            .base_line = dg.decl.navSrcLine(zcu),
             .prev_dbg_line = 0,
             .prev_dbg_column = 0,
             .err_ret_trace = err_ret_trace,
@@ -2067,7 +2067,7 @@ pub const Object = struct {
                     try o.builder.metadataString(name),
                     file,
                     scope,
-                    owner_decl.src_line + 1, // Line
+                    owner_decl.typeSrcLine(mod) + 1, // Line
                     try o.lowerDebugType(int_ty),
                     ty.abiSize(mod) * 8,
                     (ty.abiAlignment(mod).toByteUnits() orelse 0) * 8,
@@ -2237,7 +2237,7 @@ pub const Object = struct {
                     try o.builder.metadataString(name),
                     try o.getDebugFile(mod.namespacePtr(owner_decl.src_namespace).file_scope),
                     try o.namespaceToDebugScope(owner_decl.src_namespace),
-                    owner_decl.src_line + 1, // Line
+                    owner_decl.typeSrcLine(mod) + 1, // Line
                     .none, // Underlying type
                     0, // Size
                     0, // Align
@@ -2867,7 +2867,7 @@ pub const Object = struct {
             try o.builder.metadataString(decl.name.toSlice(&mod.intern_pool)), // TODO use fully qualified name
             try o.getDebugFile(mod.namespacePtr(decl.src_namespace).file_scope),
             try o.namespaceToDebugScope(decl.src_namespace),
-            decl.src_line + 1,
+            decl.typeSrcLine(mod) + 1,
             .none,
             0,
             0,
@@ -4762,7 +4762,7 @@ pub const DeclGen = struct {
                 else => try o.lowerValue(init_val),
             }, &o.builder);
 
-            const line_number = decl.src_line + 1;
+            const line_number = decl.navSrcLine(zcu) + 1;
             const is_internal_linkage = !o.module.decl_exports.contains(decl_index);
 
             const namespace = zcu.namespacePtr(decl.src_namespace);
@@ -5188,7 +5188,7 @@ pub const FuncGen = struct {
 
             self.file = try o.getDebugFile(namespace.file_scope);
 
-            const line_number = decl.src_line + 1;
+            const line_number = decl.navSrcLine(zcu) + 1;
             self.inlined = self.wip.debug_location;
 
             const fqn = try decl.fullyQualifiedName(zcu);
@@ -5217,7 +5217,7 @@ pub const FuncGen = struct {
                 o.debug_compile_unit,
             );
 
-            self.base_line = decl.src_line;
+            self.base_line = decl.navSrcLine(zcu);
             const inlined_at_location = try self.wip.debug_location.toMetadata(&o.builder);
             self.wip.debug_location = .{
                 .location = .{
@@ -8857,7 +8857,7 @@ pub const FuncGen = struct {
         const src_index = self.air.instructions.items(.data)[@intFromEnum(inst)].arg.src_index;
         const func_index = self.dg.decl.getOwnedFunctionIndex();
         const func = mod.funcInfo(func_index);
-        const lbrace_line = mod.declPtr(func.owner_decl).src_line + func.lbrace_line + 1;
+        const lbrace_line = mod.declPtr(func.owner_decl).navSrcLine(mod) + func.lbrace_line + 1;
         const lbrace_col = func.lbrace_column + 1;
 
         const debug_parameter = try o.builder.debugParameter(
diff --git a/src/codegen/spirv.zig b/src/codegen/spirv.zig
index 8168cce996..ee163c3154 100644
--- a/src/codegen/spirv.zig
+++ b/src/codegen/spirv.zig
@@ -212,7 +212,7 @@ pub const Object = struct {
                 false => .{ .unstructured = .{} },
             },
             .current_block_label = undefined,
-            .base_line = decl.src_line,
+            .base_line = decl.navSrcLine(mod),
         };
         defer decl_gen.deinit();
 
@@ -6345,7 +6345,7 @@ const DeclGen = struct {
         const decl = mod.funcOwnerDeclPtr(extra.data.func);
         const old_base_line = self.base_line;
         defer self.base_line = old_base_line;
-        self.base_line = decl.src_line;
+        self.base_line = decl.navSrcLine(mod);
         return self.lowerBlock(inst, @ptrCast(self.air.extra[extra.end..][0..extra.data.body_len]));
     }
 
diff --git a/src/link/Dwarf.zig b/src/link/Dwarf.zig
index ccfdfd0dbf..7d576abbb4 100644
--- a/src/link/Dwarf.zig
+++ b/src/link/Dwarf.zig
@@ -948,8 +948,8 @@ pub const DeclState = struct {
             leb128.writeUnsignedFixed(4, self.dbg_line.addManyAsArrayAssumeCapacity(4), new_file);
         }
 
-        const old_src_line: i33 = self.mod.declPtr(old_func_info.owner_decl).src_line;
-        const new_src_line: i33 = self.mod.declPtr(new_func_info.owner_decl).src_line;
+        const old_src_line: i33 = self.mod.declPtr(old_func_info.owner_decl).navSrcLine(self.mod);
+        const new_src_line: i33 = self.mod.declPtr(new_func_info.owner_decl).navSrcLine(self.mod);
         if (new_src_line != old_src_line) {
             self.dbg_line.appendAssumeCapacity(DW.LNS.advance_line);
             leb128.writeSignedFixed(5, self.dbg_line.addManyAsArrayAssumeCapacity(5), new_src_line - old_src_line);
@@ -1116,11 +1116,11 @@ pub fn initDeclState(self: *Dwarf, mod: *Module, decl_index: InternPool.DeclInde
             decl_state.dbg_line_func = decl.val.toIntern();
             const func = decl.val.getFunction(mod).?;
             log.debug("decl.src_line={d}, func.lbrace_line={d}, func.rbrace_line={d}", .{
-                decl.src_line,
+                decl.navSrcLine(mod),
                 func.lbrace_line,
                 func.rbrace_line,
             });
-            const line: u28 = @intCast(decl.src_line + func.lbrace_line);
+            const line: u28 = @intCast(decl.navSrcLine(mod) + func.lbrace_line);
 
             dbg_line_buffer.appendSliceAssumeCapacity(&.{
                 DW.LNS.extended_op,
@@ -1702,11 +1702,11 @@ pub fn updateDeclLineNumber(self: *Dwarf, mod: *Module, decl_index: InternPool.D
     const decl = mod.declPtr(decl_index);
     const func = decl.val.getFunction(mod).?;
     log.debug("decl.src_line={d}, func.lbrace_line={d}, func.rbrace_line={d}", .{
-        decl.src_line,
+        decl.navSrcLine(mod),
         func.lbrace_line,
         func.rbrace_line,
     });
-    const line: u28 = @intCast(decl.src_line + func.lbrace_line);
+    const line: u28 = @intCast(decl.navSrcLine(mod) + func.lbrace_line);
     var data: [4]u8 = undefined;
     leb128.writeUnsignedFixed(4, &data, line);
 
diff --git a/src/print_zir.zig b/src/print_zir.zig
index 6caf6a5d91..d064f02a8b 100644
--- a/src/print_zir.zig
+++ b/src/print_zir.zig
@@ -583,7 +583,7 @@ const Writer = struct {
 
             .reify => {
                 const inst_data = self.code.extraData(Zir.Inst.Reify, extended.operand).data;
-                try stream.print("{d}, ", .{inst_data.src_line});
+                try stream.print("line({d}), ", .{inst_data.src_line});
                 try self.writeInstRef(stream, inst_data.operand);
                 try stream.writeAll(")) ");
                 const prev_parent_decl_node = self.parent_decl_node;
@@ -2749,7 +2749,7 @@ const Writer = struct {
             extra.data.src_hash_3,
         };
         const src_hash_bytes: [16]u8 = @bitCast(src_hash_arr);
-        try stream.print(" line(+{d}) hash({})", .{ extra.data.line_offset, std.fmt.fmtSliceHexLower(&src_hash_bytes) });
+        try stream.print(" line({d}) hash({})", .{ extra.data.src_line, std.fmt.fmtSliceHexLower(&src_hash_bytes) });
 
         {
             const bodies = extra.data.getBodies(@intCast(extra.end), self.code);
diff --git a/src/type.zig b/src/type.zig
index 480db4e5b7..df93822273 100644
--- a/src/type.zig
+++ b/src/type.zig
@@ -11,6 +11,7 @@ const target_util = @import("target.zig");
 const Sema = @import("Sema.zig");
 const InternPool = @import("InternPool.zig");
 const Alignment = InternPool.Alignment;
+const Zir = std.zig.Zir;
 
 /// Both types and values are canonically represented by a single 32-bit integer
 /// which is an index into an `InternPool` data structure.
@@ -3340,7 +3341,7 @@ pub const Type = struct {
                 .struct_type, .union_type, .opaque_type, .enum_type => |info| switch (info) {
                     .declared => |d| d.zir_index,
                     .reified => |r| r.zir_index,
-                    .generated_tag => |gt| ip.loadUnionType(gt.union_type).zir_index, // must be declared since we can't generate tags when reifying
+                    .generated_tag => |gt| ip.loadUnionType(gt.union_type).zir_index,
                     .empty_struct => return null,
                 },
                 else => return null,
@@ -3440,6 +3441,33 @@ pub const Type = struct {
         };
     }
 
+    pub fn typeDeclSrcLine(ty: Type, zcu: *const Zcu) ?u32 {
+        const ip = &zcu.intern_pool;
+        const tracked = switch (ip.indexToKey(ty.toIntern())) {
+            .struct_type, .union_type, .opaque_type, .enum_type => |info| switch (info) {
+                .declared => |d| d.zir_index,
+                .reified => |r| r.zir_index,
+                .generated_tag => |gt| ip.loadUnionType(gt.union_type).zir_index,
+                .empty_struct => return null,
+            },
+            else => return null,
+        };
+        const info = tracked.resolveFull(&zcu.intern_pool);
+        const file = zcu.import_table.values()[zcu.path_digest_map.getIndex(info.path_digest).?];
+        assert(file.zir_loaded);
+        const zir = file.zir;
+        const inst = zir.instructions.get(@intFromEnum(info.inst));
+        assert(inst.tag == .extended);
+        return switch (inst.data.extended.opcode) {
+            .struct_decl => zir.extraData(Zir.Inst.StructDecl, inst.data.extended.operand).data.src_line,
+            .union_decl => zir.extraData(Zir.Inst.UnionDecl, inst.data.extended.operand).data.src_line,
+            .enum_decl => zir.extraData(Zir.Inst.EnumDecl, inst.data.extended.operand).data.src_line,
+            .opaque_decl => zir.extraData(Zir.Inst.OpaqueDecl, inst.data.extended.operand).data.src_line,
+            .reify => zir.extraData(Zir.Inst.Reify, inst.data.extended.operand).data.src_line,
+            else => unreachable,
+        };
+    }
+
     /// Given a namespace type, returns its list of caotured values.
     pub fn getCaptures(ty: Type, zcu: *const Zcu) InternPool.CaptureValue.Slice {
         const ip = &zcu.intern_pool;