diff --git a/doc/manual/rl-next/formal-order.md b/doc/manual/rl-next/formal-order.md
new file mode 100644
index 000000000..12628e318
--- /dev/null
+++ b/doc/manual/rl-next/formal-order.md
@@ -0,0 +1,7 @@
+---
+synopsis: consistent order of lambda formals in printed expressions
+prs: 9874
+---
+
+Always print lambda formals in lexicographic order rather than the internal, creation-time based symbol order.
+This makes printed formals independent of the context they appear in.
diff --git a/doc/manual/rl-next/inherit-error-positions.md b/doc/manual/rl-next/inherit-error-positions.md
new file mode 100644
index 000000000..643080e9e
--- /dev/null
+++ b/doc/manual/rl-next/inherit-error-positions.md
@@ -0,0 +1,6 @@
+---
+synopsis: fix duplicate attribute error positions for `inherit`
+prs: 9874
+---
+
+When an inherit caused a duplicate attribute error the position of the error was not reported correctly, placing the error with the inherit itself or at the start of the bindings block instead of the offending attribute name.
diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index 722ff6908..bbccfcd29 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -949,12 +949,11 @@ void EvalState::mkThunk_(Value & v, Expr * expr)
 
 void EvalState::mkPos(Value & v, PosIdx p)
 {
-    auto pos = positions[p];
-    if (auto path = std::get_if<SourcePath>(&pos.origin)) {
+    auto origin = positions.originOf(p);
+    if (auto path = std::get_if<SourcePath>(&origin)) {
         auto attrs = buildBindings(3);
         attrs.alloc(sFile).mkString(path->path.abs());
-        attrs.alloc(sLine).mkInt(pos.line);
-        attrs.alloc(sColumn).mkInt(pos.column);
+        makePositionThunks(*this, p, attrs.alloc(sLine), attrs.alloc(sColumn));
         v.mkAttrs(attrs);
     } else
         v.mkNull();
@@ -2777,9 +2776,12 @@ Expr * EvalState::parseExprFromFile(const SourcePath & path, std::shared_ptr<Sta
 
 Expr * EvalState::parseExprFromString(std::string s_, const SourcePath & basePath, std::shared_ptr<StaticEnv> & staticEnv)
 {
-    auto s = make_ref<std::string>(std::move(s_));
-    s->append("\0\0", 2);
-    return parse(s->data(), s->size(), Pos::String{.source = s}, basePath, staticEnv);
+    // NOTE this method (and parseStdin) must take care to *fully copy* their input
+    // into their respective Pos::Origin until the parser stops overwriting its input
+    // data.
+    auto s = make_ref<std::string>(s_);
+    s_.append("\0\0", 2);
+    return parse(s_.data(), s_.size(), Pos::String{.source = s}, basePath, staticEnv);
 }
 
 
@@ -2791,12 +2793,15 @@ Expr * EvalState::parseExprFromString(std::string s, const SourcePath & basePath
 
 Expr * EvalState::parseStdin()
 {
+    // NOTE this method (and parseExprFromString) must take care to *fully copy* their
+    // input into their respective Pos::Origin until the parser stops overwriting its
+    // input data.
     //Activity act(*logger, lvlTalkative, "parsing standard input");
     auto buffer = drainFD(0);
     // drainFD should have left some extra space for terminators
     buffer.append("\0\0", 2);
-    auto s = make_ref<std::string>(std::move(buffer));
-    return parse(s->data(), s->size(), Pos::Stdin{.source = s}, rootPath("."), staticBaseEnv);
+    auto s = make_ref<std::string>(buffer);
+    return parse(buffer.data(), buffer.size(), Pos::Stdin{.source = s}, rootPath("."), staticBaseEnv);
 }
 
 
diff --git a/src/libexpr/flake/flake.cc b/src/libexpr/flake/flake.cc
index 4a69bb381..bca473453 100644
--- a/src/libexpr/flake/flake.cc
+++ b/src/libexpr/flake/flake.cc
@@ -212,11 +212,10 @@ static Flake readFlake(
 {
     auto flakePath = rootDir / CanonPath(resolvedRef.subdir) / "flake.nix";
 
+    // NOTE evalFile forces vInfo to be an attrset because mustBeTrivial is true.
     Value vInfo;
     state.evalFile(flakePath, vInfo, true);
 
-    expectType(state, nAttrs, vInfo, state.positions.add(Pos::Origin(rootDir), 1, 1));
-
     Flake flake {
         .originalRef = originalRef,
         .resolvedRef = resolvedRef,
diff --git a/src/libexpr/lexer.l b/src/libexpr/lexer.l
index 5b26d6927..ee2b6b807 100644
--- a/src/libexpr/lexer.l
+++ b/src/libexpr/lexer.l
@@ -33,33 +33,16 @@ namespace nix {
 
 static void initLoc(YYLTYPE * loc)
 {
-    loc->first_line = loc->last_line = 1;
-    loc->first_column = loc->last_column = 1;
+    loc->first_line = loc->last_line = 0;
+    loc->first_column = loc->last_column = 0;
 }
 
 static void adjustLoc(YYLTYPE * loc, const char * s, size_t len)
 {
     loc->stash();
 
-    loc->first_line = loc->last_line;
     loc->first_column = loc->last_column;
-
-    for (size_t i = 0; i < len; i++) {
-       switch (*s++) {
-       case '\r':
-           if (*s == '\n') { /* cr/lf */
-               i++;
-               s++;
-           }
-           /* fall through */
-       case '\n':
-           ++loc->last_line;
-           loc->last_column = 1;
-           break;
-       default:
-           ++loc->last_column;
-       }
-    }
+    loc->last_column += len;
 }
 
 
diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc
index 4b805d710..5bdc466eb 100644
--- a/src/libexpr/nixexpr.cc
+++ b/src/libexpr/nixexpr.cc
@@ -149,7 +149,10 @@ void ExprLambda::show(const SymbolTable & symbols, std::ostream & str) const
     if (hasFormals()) {
         str << "{ ";
         bool first = true;
-        for (auto & i : formals->formals) {
+        // the natural Symbol ordering is by creation time, which can lead to the
+        // same expression being printed in two different ways depending on its
+        // context. always use lexicographic ordering to avoid this.
+        for (auto & i : formals->lexicographicOrder(symbols)) {
             if (first) first = false; else str << ", ";
             str << symbols[i.name];
             if (i.def) {
@@ -580,6 +583,39 @@ std::string ExprLambda::showNamePos(const EvalState & state) const
 
 
 
+/* Position table. */
+
+Pos PosTable::operator[](PosIdx p) const
+{
+    auto origin = resolve(p);
+    if (!origin)
+        return {};
+
+    const auto offset = origin->offsetOf(p);
+
+    Pos result{0, 0, origin->origin};
+    auto lines = this->lines.lock();
+    auto linesForInput = (*lines)[origin->offset];
+
+    if (linesForInput.empty()) {
+        auto source = result.getSource().value_or("");
+        const char * begin = source.data();
+        for (Pos::LinesIterator it(source), end; it != end; it++)
+            linesForInput.push_back(it->data() - begin);
+        if (linesForInput.empty())
+            linesForInput.push_back(0);
+    }
+    // as above: the first line starts at byte 0 and is always present
+    auto lineStartOffset = std::prev(
+        std::upper_bound(linesForInput.begin(), linesForInput.end(), offset));
+
+    result.line = 1 + (lineStartOffset - linesForInput.begin());
+    result.column = 1 + (offset - *lineStartOffset);
+    return result;
+}
+
+
+
 /* Symbol table. */
 
 size_t SymbolTable::totalSize() const
diff --git a/src/libexpr/nixexpr.hh b/src/libexpr/nixexpr.hh
index 94356759b..e3cae8385 100644
--- a/src/libexpr/nixexpr.hh
+++ b/src/libexpr/nixexpr.hh
@@ -7,7 +7,6 @@
 #include "value.hh"
 #include "symbol-table.hh"
 #include "error.hh"
-#include "chunked-vector.hh"
 #include "position.hh"
 #include "eval-error.hh"
 #include "pos-idx.hh"
diff --git a/src/libexpr/parser-state.hh b/src/libexpr/parser-state.hh
index 34aef661f..024e79c43 100644
--- a/src/libexpr/parser-state.hh
+++ b/src/libexpr/parser-state.hh
@@ -24,20 +24,15 @@ struct ParserLocation
     int last_line, last_column;
 
     // backup to recover from yyless(0)
-    int stashed_first_line, stashed_first_column;
-    int stashed_last_line, stashed_last_column;
+    int stashed_first_column, stashed_last_column;
 
     void stash() {
-        stashed_first_line = first_line;
         stashed_first_column = first_column;
-        stashed_last_line = last_line;
         stashed_last_column = last_column;
     }
 
     void unstash() {
-        first_line = stashed_first_line;
         first_column = stashed_first_column;
-        last_line = stashed_last_line;
         last_column = stashed_last_column;
     }
 };
@@ -276,7 +271,7 @@ inline Expr * ParserState::stripIndentation(const PosIdx pos,
 
 inline PosIdx ParserState::at(const ParserLocation & loc)
 {
-    return positions.add(origin, loc.first_line, loc.first_column);
+    return positions.add(origin, loc.first_column);
 }
 
 }
diff --git a/src/libexpr/parser.y b/src/libexpr/parser.y
index b0aee7b41..bff066170 100644
--- a/src/libexpr/parser.y
+++ b/src/libexpr/parser.y
@@ -64,6 +64,10 @@ using namespace nix;
 
 void yyerror(YYLTYPE * loc, yyscan_t scanner, ParserState * state, const char * error)
 {
+    if (std::string_view(error).starts_with("syntax error, unexpected end of file")) {
+        loc->first_column = loc->last_column;
+        loc->first_line = loc->last_line;
+    }
     throw ParseError({
         .msg = HintFmt(error),
         .pos = state->positions[state->at(*loc)]
@@ -87,6 +91,7 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParserState * state, const char *
   nix::StringToken uri;
   nix::StringToken str;
   std::vector<nix::AttrName> * attrNames;
+  std::vector<std::pair<nix::AttrName, nix::PosIdx>> * inheritAttrs;
   std::vector<std::pair<nix::PosIdx, nix::Expr *>> * string_parts;
   std::vector<std::pair<nix::PosIdx, std::variant<nix::Expr *, nix::StringToken>>> * ind_string_parts;
 }
@@ -97,7 +102,8 @@ void yyerror(YYLTYPE * loc, yyscan_t scanner, ParserState * state, const char *
 %type <attrs> binds
 %type <formals> formals
 %type <formal> formal
-%type <attrNames> attrs attrpath
+%type <attrNames> attrpath
+%type <inheritAttrs> attrs
 %type <string_parts> string_parts_interpolated
 %type <ind_string_parts> ind_string_parts
 %type <e> path_start string_parts string_attr
@@ -309,13 +315,12 @@ binds
   : binds attrpath '=' expr ';' { $$ = $1; state->addAttr($$, std::move(*$2), $4, state->at(@2)); delete $2; }
   | binds INHERIT attrs ';'
     { $$ = $1;
-      for (auto & i : *$3) {
+      for (auto & [i, iPos] : *$3) {
           if ($$->attrs.find(i.symbol) != $$->attrs.end())
-              state->dupAttr(i.symbol, state->at(@3), $$->attrs[i.symbol].pos);
-          auto pos = state->at(@3);
+              state->dupAttr(i.symbol, iPos, $$->attrs[i.symbol].pos);
           $$->attrs.emplace(
               i.symbol,
-              ExprAttrs::AttrDef(new ExprVar(CUR_POS, i.symbol), pos, ExprAttrs::AttrDef::Kind::Inherited));
+              ExprAttrs::AttrDef(new ExprVar(iPos, i.symbol), iPos, ExprAttrs::AttrDef::Kind::Inherited));
       }
       delete $3;
     }
@@ -325,14 +330,14 @@ binds
           $$->inheritFromExprs = std::make_unique<std::vector<Expr *>>();
       $$->inheritFromExprs->push_back($4);
       auto from = new nix::ExprInheritFrom(state->at(@4), $$->inheritFromExprs->size() - 1);
-      for (auto & i : *$6) {
+      for (auto & [i, iPos] : *$6) {
           if ($$->attrs.find(i.symbol) != $$->attrs.end())
-              state->dupAttr(i.symbol, state->at(@6), $$->attrs[i.symbol].pos);
+              state->dupAttr(i.symbol, iPos, $$->attrs[i.symbol].pos);
           $$->attrs.emplace(
               i.symbol,
               ExprAttrs::AttrDef(
-                  new ExprSelect(CUR_POS, from, i.symbol),
-                  state->at(@6),
+                  new ExprSelect(iPos, from, i.symbol),
+                  iPos,
                   ExprAttrs::AttrDef::Kind::InheritedFrom));
       }
       delete $6;
@@ -341,12 +346,12 @@ binds
   ;
 
 attrs
-  : attrs attr { $$ = $1; $1->push_back(AttrName(state->symbols.create($2))); }
+  : attrs attr { $$ = $1; $1->emplace_back(AttrName(state->symbols.create($2)), state->at(@2)); }
   | attrs string_attr
     { $$ = $1;
       ExprString * str = dynamic_cast<ExprString *>($2);
       if (str) {
-          $$->push_back(AttrName(state->symbols.create(str->s)));
+          $$->emplace_back(AttrName(state->symbols.create(str->s)), state->at(@2));
           delete str;
       } else
           throw ParseError({
@@ -354,7 +359,7 @@ attrs
               .pos = state->positions[state->at(@2)]
           });
     }
-  | { $$ = new AttrPath; }
+  | { $$ = new std::vector<std::pair<AttrName, PosIdx>>; }
   ;
 
 attrpath
@@ -433,7 +438,7 @@ Expr * parseExprFromBuf(
         .symbols = symbols,
         .positions = positions,
         .basePath = basePath,
-        .origin = {origin},
+        .origin = positions.addOrigin(origin, length),
         .rootFS = rootFS,
         .s = astSymbols,
     };
diff --git a/src/libexpr/pos-idx.hh b/src/libexpr/pos-idx.hh
index 9949f1dc5..e94fd85c6 100644
--- a/src/libexpr/pos-idx.hh
+++ b/src/libexpr/pos-idx.hh
@@ -6,6 +6,7 @@ namespace nix {
 
 class PosIdx
 {
+    friend struct LazyPosAcessors;
     friend class PosTable;
 
 private:
diff --git a/src/libexpr/pos-table.hh b/src/libexpr/pos-table.hh
index 1decf3c85..8a0a3ba86 100644
--- a/src/libexpr/pos-table.hh
+++ b/src/libexpr/pos-table.hh
@@ -7,6 +7,7 @@
 #include "chunked-vector.hh"
 #include "pos-idx.hh"
 #include "position.hh"
+#include "sync.hh"
 
 namespace nix {
 
@@ -17,66 +18,69 @@ public:
     {
         friend PosTable;
     private:
-        // must always be invalid by default, add() replaces this with the actual value.
-        // subsequent add() calls use this index as a token to quickly check whether the
-        // current origins.back() can be reused or not.
-        mutable uint32_t idx = std::numeric_limits<uint32_t>::max();
+        uint32_t offset;
 
-        // Used for searching in PosTable::[].
-        explicit Origin(uint32_t idx)
-            : idx(idx)
-            , origin{std::monostate()}
-        {
-        }
+        Origin(Pos::Origin origin, uint32_t offset, size_t size):
+            offset(offset), origin(origin), size(size)
+        {}
 
     public:
         const Pos::Origin origin;
+        const size_t size;
 
-        Origin(Pos::Origin origin)
-            : origin(origin)
+        uint32_t offsetOf(PosIdx p) const
         {
+            return p.id - 1 - offset;
         }
     };
 
-    struct Offset
-    {
-        uint32_t line, column;
-    };
-
 private:
-    std::vector<Origin> origins;
-    ChunkedVector<Offset, 8192> offsets;
+    using Lines = std::vector<uint32_t>;
 
-public:
-    PosTable()
-        : offsets(1024)
-    {
-        origins.reserve(1024);
-    }
+    std::map<uint32_t, Origin> origins;
+    mutable Sync<std::map<uint32_t, Lines>> lines;
 
-    PosIdx add(const Origin & origin, uint32_t line, uint32_t column)
+    const Origin * resolve(PosIdx p) const
     {
-        const auto idx = offsets.add({line, column}).second;
-        if (origins.empty() || origins.back().idx != origin.idx) {
-            origin.idx = idx;
-            origins.push_back(origin);
-        }
-        return PosIdx(idx + 1);
-    }
+        if (p.id == 0)
+            return nullptr;
 
-    Pos operator[](PosIdx p) const
-    {
-        if (p.id == 0 || p.id > offsets.size())
-            return {};
         const auto idx = p.id - 1;
         /* we want the last key <= idx, so we'll take prev(first key > idx).
-           this is guaranteed to never rewind origin.begin because the first
-           key is always 0. */
-        const auto pastOrigin = std::upper_bound(
-            origins.begin(), origins.end(), Origin(idx), [](const auto & a, const auto & b) { return a.idx < b.idx; });
-        const auto origin = *std::prev(pastOrigin);
-        const auto offset = offsets[idx];
-        return {offset.line, offset.column, origin.origin};
+            this is guaranteed to never rewind origin.begin because the first
+            key is always 0. */
+        const auto pastOrigin = origins.upper_bound(idx);
+        return &std::prev(pastOrigin)->second;
+    }
+
+public:
+    Origin addOrigin(Pos::Origin origin, size_t size)
+    {
+        uint32_t offset = 0;
+        if (auto it = origins.rbegin(); it != origins.rend())
+            offset = it->first + it->second.size;
+        // +1 because all PosIdx are offset by 1 to begin with, and
+        // another +1 to ensure that all origins can point to EOF, eg
+        // on (invalid) empty inputs.
+        if (2 + offset + size < offset)
+            return Origin{origin, offset, 0};
+        return origins.emplace(offset, Origin{origin, offset, size}).first->second;
+    }
+
+    PosIdx add(const Origin & origin, size_t offset)
+    {
+        if (offset > origin.size)
+            return PosIdx();
+        return PosIdx(1 + origin.offset + offset);
+    }
+
+    Pos operator[](PosIdx p) const;
+
+    Pos::Origin originOf(PosIdx p) const
+    {
+        if (auto o = resolve(p))
+            return o->origin;
+        return std::monostate{};
     }
 };
 
diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 78f7f71ed..a7687fa06 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -2524,6 +2524,54 @@ static RegisterPrimOp primop_unsafeGetAttrPos(PrimOp {
     .fun = prim_unsafeGetAttrPos,
 });
 
+// access to exact position information (ie, line and colum numbers) is deferred
+// due to the cost associated with calculating that information and how rarely
+// it is used in practice. this is achieved by creating thunks to otherwise
+// inaccessible primops that are not exposed as __op or under builtins to turn
+// the internal PosIdx back into a line and column number, respectively. exposing
+// these primops in any way would at best be not useful and at worst create wildly
+// indeterministic eval results depending on parse order of files.
+//
+// in a simpler world this would instead be implemented as another kind of thunk,
+// but each type of thunk has an associated runtime cost in the current evaluator.
+// as with black holes this cost is too high to justify another thunk type to check
+// for in the very hot path that is forceValue.
+static struct LazyPosAcessors {
+    PrimOp primop_lineOfPos{
+        .arity = 1,
+        .fun = [] (EvalState & state, PosIdx pos, Value * * args, Value & v) {
+            v.mkInt(state.positions[PosIdx(args[0]->integer)].line);
+        }
+    };
+    PrimOp primop_columnOfPos{
+        .arity = 1,
+        .fun = [] (EvalState & state, PosIdx pos, Value * * args, Value & v) {
+            v.mkInt(state.positions[PosIdx(args[0]->integer)].column);
+        }
+    };
+
+    Value lineOfPos, columnOfPos;
+
+    LazyPosAcessors()
+    {
+        lineOfPos.mkPrimOp(&primop_lineOfPos);
+        columnOfPos.mkPrimOp(&primop_columnOfPos);
+    }
+
+    void operator()(EvalState & state, const PosIdx pos, Value & line, Value & column)
+    {
+        Value * posV = state.allocValue();
+        posV->mkInt(pos.id);
+        line.mkApp(&lineOfPos, posV);
+        column.mkApp(&columnOfPos, posV);
+    }
+} makeLazyPosAccessors;
+
+void makePositionThunks(EvalState & state, const PosIdx pos, Value & line, Value & column)
+{
+    makeLazyPosAccessors(state, pos, line, column);
+}
+
 /* Dynamic version of the `?' operator. */
 static void prim_hasAttr(EvalState & state, const PosIdx pos, Value * * args, Value & v)
 {
diff --git a/src/libexpr/primops.hh b/src/libexpr/primops.hh
index 45486608f..9f76975db 100644
--- a/src/libexpr/primops.hh
+++ b/src/libexpr/primops.hh
@@ -51,4 +51,6 @@ void prim_importNative(EvalState & state, const PosIdx pos, Value * * args, Valu
  */
 void prim_exec(EvalState & state, const PosIdx pos, Value * * args, Value & v);
 
+void makePositionThunks(EvalState & state, const PosIdx pos, Value & line, Value & column);
+
 }
diff --git a/src/libutil/position.cc b/src/libutil/position.cc
index b39a5a1d4..724e560b7 100644
--- a/src/libutil/position.cc
+++ b/src/libutil/position.cc
@@ -29,32 +29,17 @@ std::optional<LinesOfCode> Pos::getCodeLines() const
         return std::nullopt;
 
     if (auto source = getSource()) {
-
-        std::istringstream iss(*source);
-        // count the newlines.
-        int count = 0;
-        std::string curLine;
-        int pl = line - 1;
-
+        LinesIterator lines(*source), end;
         LinesOfCode loc;
 
-        do {
-            std::getline(iss, curLine);
-            ++count;
-            if (count < pl)
-                ;
-            else if (count == pl) {
-                loc.prevLineOfCode = curLine;
-            } else if (count == pl + 1) {
-                loc.errLineOfCode = curLine;
-            } else if (count == pl + 2) {
-                loc.nextLineOfCode = curLine;
-                break;
-            }
-
-            if (!iss.good())
-                break;
-        } while (true);
+        if (line > 1)
+            std::advance(lines, line - 2);
+        if (lines != end && line > 1)
+            loc.prevLineOfCode = *lines++;
+        if (lines != end)
+            loc.errLineOfCode = *lines++;
+        if (lines != end)
+            loc.nextLineOfCode = *lines++;
 
         return loc;
     }
@@ -109,4 +94,26 @@ std::ostream & operator<<(std::ostream & str, const Pos & pos)
     return str;
 }
 
+void Pos::LinesIterator::bump(bool atFirst)
+{
+    if (!atFirst) {
+        pastEnd = input.empty();
+        if (!input.empty() && input[0] == '\r')
+            input.remove_prefix(1);
+        if (!input.empty() && input[0] == '\n')
+            input.remove_prefix(1);
+    }
+
+    // nix line endings are not only \n as eg std::getline assumes, but also
+    // \r\n **and \r alone**. not treating them all the same causes error
+    // reports to not match with line numbers as the parser expects them.
+    auto eol = input.find_first_of("\r\n");
+
+    if (eol > input.size())
+        eol = input.size();
+
+    curLine = input.substr(0, eol);
+    input.remove_prefix(eol);
+}
+
 }
diff --git a/src/libutil/position.hh b/src/libutil/position.hh
index a184997ed..9bdf3b4b5 100644
--- a/src/libutil/position.hh
+++ b/src/libutil/position.hh
@@ -67,6 +67,48 @@ struct Pos
     bool operator==(const Pos & rhs) const = default;
     bool operator!=(const Pos & rhs) const = default;
     bool operator<(const Pos & rhs) const;
+
+    struct LinesIterator {
+        using difference_type = size_t;
+        using value_type = std::string_view;
+        using reference = const std::string_view &;
+        using pointer = const std::string_view *;
+        using iterator_category = std::input_iterator_tag;
+
+        LinesIterator(): pastEnd(true) {}
+        explicit LinesIterator(std::string_view input): input(input), pastEnd(input.empty()) {
+            if (!pastEnd)
+                bump(true);
+        }
+
+        LinesIterator & operator++() {
+            bump(false);
+            return *this;
+        }
+        LinesIterator operator++(int) {
+            auto result = *this;
+            ++*this;
+            return result;
+        }
+
+        reference operator*() const { return curLine; }
+        pointer operator->() const { return &curLine; }
+
+        bool operator!=(const LinesIterator & other) const {
+            return !(*this == other);
+        }
+        bool operator==(const LinesIterator & other) const {
+            return (pastEnd && other.pastEnd)
+                || (std::forward_as_tuple(input.size(), input.data())
+                    == std::forward_as_tuple(other.input.size(), other.input.data()));
+        }
+
+    private:
+        std::string_view input, curLine;
+        bool pastEnd = false;
+
+        void bump(bool atFirst);
+    };
 };
 
 std::ostream & operator<<(std::ostream & str, const Pos & pos);
diff --git a/tests/functional/lang/eval-fail-eol-1.err.exp b/tests/functional/lang/eval-fail-eol-1.err.exp
new file mode 100644
index 000000000..3f5a5c22c
--- /dev/null
+++ b/tests/functional/lang/eval-fail-eol-1.err.exp
@@ -0,0 +1,6 @@
+error: undefined variable 'invalid'
+       at /pwd/lang/eval-fail-eol-1.nix:2:1:
+            1| # foo
+            2| invalid
+             | ^
+            3| # bar
diff --git a/tests/functional/lang/eval-fail-eol-1.nix b/tests/functional/lang/eval-fail-eol-1.nix
new file mode 100644
index 000000000..476223919
--- /dev/null
+++ b/tests/functional/lang/eval-fail-eol-1.nix
@@ -0,0 +1,3 @@
+# foo
+invalid
+# bar
diff --git a/tests/functional/lang/eval-fail-eol-2.err.exp b/tests/functional/lang/eval-fail-eol-2.err.exp
new file mode 100644
index 000000000..ff13e2d55
--- /dev/null
+++ b/tests/functional/lang/eval-fail-eol-2.err.exp
@@ -0,0 +1,6 @@
+error: undefined variable 'invalid'
+       at /pwd/lang/eval-fail-eol-2.nix:2:1:
+            1| # foo
+            2| invalid
+             | ^
+            3| # bar
diff --git a/tests/functional/lang/eval-fail-eol-2.nix b/tests/functional/lang/eval-fail-eol-2.nix
new file mode 100644
index 000000000..0cf92a425
--- /dev/null
+++ b/tests/functional/lang/eval-fail-eol-2.nix
@@ -0,0 +1,2 @@
+# foo
invalid
+# bar
diff --git a/tests/functional/lang/eval-fail-eol-3.err.exp b/tests/functional/lang/eval-fail-eol-3.err.exp
new file mode 100644
index 000000000..ada3c5ecd
--- /dev/null
+++ b/tests/functional/lang/eval-fail-eol-3.err.exp
@@ -0,0 +1,6 @@
+error: undefined variable 'invalid'
+       at /pwd/lang/eval-fail-eol-3.nix:2:1:
+            1| # foo
+            2| invalid
+             | ^
+            3| # bar
diff --git a/tests/functional/lang/eval-fail-eol-3.nix b/tests/functional/lang/eval-fail-eol-3.nix
new file mode 100644
index 000000000..33422452d
--- /dev/null
+++ b/tests/functional/lang/eval-fail-eol-3.nix
@@ -0,0 +1,3 @@
+# foo
+invalid
+# bar
diff --git a/tests/functional/lang/eval-okay-inherit-attr-pos.exp b/tests/functional/lang/eval-okay-inherit-attr-pos.exp
new file mode 100644
index 000000000..e87d037c6
--- /dev/null
+++ b/tests/functional/lang/eval-okay-inherit-attr-pos.exp
@@ -0,0 +1 @@
+[ { column = 17; file = "/pwd/lang/eval-okay-inherit-attr-pos.nix"; line = 4; } { column = 19; file = "/pwd/lang/eval-okay-inherit-attr-pos.nix"; line = 4; } { column = 21; file = "/pwd/lang/eval-okay-inherit-attr-pos.nix"; line = 5; } { column = 23; file = "/pwd/lang/eval-okay-inherit-attr-pos.nix"; line = 5; } ]
diff --git a/tests/functional/lang/eval-okay-inherit-attr-pos.nix b/tests/functional/lang/eval-okay-inherit-attr-pos.nix
new file mode 100644
index 000000000..017ab1d36
--- /dev/null
+++ b/tests/functional/lang/eval-okay-inherit-attr-pos.nix
@@ -0,0 +1,12 @@
+let
+  d = 0;
+  x = 1;
+  y = { inherit d x; };
+  z = { inherit (y) d x; };
+in
+  [
+    (builtins.unsafeGetAttrPos "d" y)
+    (builtins.unsafeGetAttrPos "x" y)
+    (builtins.unsafeGetAttrPos "d" z)
+    (builtins.unsafeGetAttrPos "x" z)
+  ]
diff --git a/tests/functional/lang/parse-fail-dup-attrs-1.err.exp b/tests/functional/lang/parse-fail-dup-attrs-1.err.exp
index 6c3a3510c..ffb5198c1 100644
--- a/tests/functional/lang/parse-fail-dup-attrs-1.err.exp
+++ b/tests/functional/lang/parse-fail-dup-attrs-1.err.exp
@@ -3,3 +3,4 @@ error: attribute 'x' already defined at «stdin»:1:3
             2|   y = 456;
             3|   x = 789;
              |   ^
+            4| }
diff --git a/tests/functional/lang/parse-fail-dup-attrs-2.err.exp b/tests/functional/lang/parse-fail-dup-attrs-2.err.exp
index fecdece20..3105e60de 100644
--- a/tests/functional/lang/parse-fail-dup-attrs-2.err.exp
+++ b/tests/functional/lang/parse-fail-dup-attrs-2.err.exp
@@ -1,5 +1,6 @@
 error: attribute 'x' already defined at «stdin»:9:5
-       at «stdin»:10:17:
+       at «stdin»:10:18:
             9|     x = 789;
            10|     inherit (as) x;
-             |                 ^
+             |                  ^
+           11|   };
diff --git a/tests/functional/lang/parse-fail-dup-attrs-3.err.exp b/tests/functional/lang/parse-fail-dup-attrs-3.err.exp
index fecdece20..3105e60de 100644
--- a/tests/functional/lang/parse-fail-dup-attrs-3.err.exp
+++ b/tests/functional/lang/parse-fail-dup-attrs-3.err.exp
@@ -1,5 +1,6 @@
 error: attribute 'x' already defined at «stdin»:9:5
-       at «stdin»:10:17:
+       at «stdin»:10:18:
             9|     x = 789;
            10|     inherit (as) x;
-             |                 ^
+             |                  ^
+           11|   };
diff --git a/tests/functional/lang/parse-fail-dup-attrs-4.err.exp b/tests/functional/lang/parse-fail-dup-attrs-4.err.exp
index f85ffea51..c98a8f8d0 100644
--- a/tests/functional/lang/parse-fail-dup-attrs-4.err.exp
+++ b/tests/functional/lang/parse-fail-dup-attrs-4.err.exp
@@ -3,3 +3,4 @@ error: attribute 'services.ssh.port' already defined at «stdin»:2:3
             2|   services.ssh.port = 22;
             3|   services.ssh.port = 23;
              |   ^
+            4| }
diff --git a/tests/functional/lang/parse-fail-dup-attrs-7.err.exp b/tests/functional/lang/parse-fail-dup-attrs-7.err.exp
index 98cea9dae..4e0a48eff 100644
--- a/tests/functional/lang/parse-fail-dup-attrs-7.err.exp
+++ b/tests/functional/lang/parse-fail-dup-attrs-7.err.exp
@@ -1,5 +1,6 @@
-error: attribute 'x' already defined at «stdin»:6:12
-       at «stdin»:7:12:
+error: attribute 'x' already defined at «stdin»:6:13
+       at «stdin»:7:13:
             6|     inherit x;
             7|     inherit x;
-             |            ^
+             |             ^
+            8|   };
diff --git a/tests/functional/lang/parse-fail-eof-in-string.err.exp b/tests/functional/lang/parse-fail-eof-in-string.err.exp
index b28d35950..17f34b62d 100644
--- a/tests/functional/lang/parse-fail-eof-in-string.err.exp
+++ b/tests/functional/lang/parse-fail-eof-in-string.err.exp
@@ -1,5 +1,5 @@
 error: syntax error, unexpected end of file, expecting '"'
-       at «stdin»:3:5:
+       at «stdin»:3:6:
             2| # Note that this file must not end with a newline.
             3| a 1"$
-             |     ^
+             |      ^
diff --git a/tests/functional/lang/parse-fail-eof-pos.err.exp b/tests/functional/lang/parse-fail-eof-pos.err.exp
new file mode 100644
index 000000000..ef9ca381c
--- /dev/null
+++ b/tests/functional/lang/parse-fail-eof-pos.err.exp
@@ -0,0 +1,5 @@
+error: syntax error, unexpected end of file
+       at «stdin»:3:1:
+            2| # no content
+            3|
+             | ^
diff --git a/tests/functional/lang/parse-fail-eof-pos.nix b/tests/functional/lang/parse-fail-eof-pos.nix
new file mode 100644
index 000000000..bd66a2c98
--- /dev/null
+++ b/tests/functional/lang/parse-fail-eof-pos.nix
@@ -0,0 +1,2 @@
+(
+# no content
diff --git a/tests/functional/lang/parse-fail-regression-20060610.err.exp b/tests/functional/lang/parse-fail-regression-20060610.err.exp
index d8875a6a5..6ae7c01bf 100644
--- a/tests/functional/lang/parse-fail-regression-20060610.err.exp
+++ b/tests/functional/lang/parse-fail-regression-20060610.err.exp
@@ -1,6 +1,6 @@
 error: undefined variable 'gcc'
-       at «stdin»:8:12:
-            7|
+       at «stdin»:9:13:
             8|   body = ({
-             |            ^
             9|     inherit gcc;
+             |             ^
+           10|   }).gcc;
diff --git a/tests/functional/lang/parse-fail-undef-var-2.err.exp b/tests/functional/lang/parse-fail-undef-var-2.err.exp
index a58d8dca4..393c454dd 100644
--- a/tests/functional/lang/parse-fail-undef-var-2.err.exp
+++ b/tests/functional/lang/parse-fail-undef-var-2.err.exp
@@ -1,5 +1,6 @@
 error: syntax error, unexpected ':', expecting '}'
        at «stdin»:3:13:
             2|
-            3|   f = {x, y :
+            3|   f = {x, y : ["baz" "bar" z "bat"]}: x + y;
              |             ^
+            4|
diff --git a/tests/functional/lang/parse-fail-utf8.err.exp b/tests/functional/lang/parse-fail-utf8.err.exp
index e83abdb9e..1c83f6eb3 100644
--- a/tests/functional/lang/parse-fail-utf8.err.exp
+++ b/tests/functional/lang/parse-fail-utf8.err.exp
@@ -1,4 +1,5 @@
 error: syntax error, unexpected invalid token, expecting end of file
        at «stdin»:1:5:
-            1| 123 Ã
+            1| 123 é 4
              |     ^
+            2|
diff --git a/tests/functional/lang/parse-okay-subversion.exp b/tests/functional/lang/parse-okay-subversion.exp
index 2303932c4..32fbba3c5 100644
--- a/tests/functional/lang/parse-okay-subversion.exp
+++ b/tests/functional/lang/parse-okay-subversion.exp
@@ -1 +1 @@
-({ fetchurl, localServer ? false, httpServer ? false, sslSupport ? false, pythonBindings ? false, javaSwigBindings ? false, javahlBindings ? false, stdenv, openssl ? null, httpd ? null, db4 ? null, expat, swig ? null, j2sdk ? null }: assert (expat != null); assert (localServer -> (db4 != null)); assert (httpServer -> ((httpd != null) && ((httpd).expat == expat))); assert (sslSupport -> ((openssl != null) && (httpServer -> ((httpd).openssl == openssl)))); assert (pythonBindings -> ((swig != null) && (swig).pythonSupport)); assert (javaSwigBindings -> ((swig != null) && (swig).javaSupport)); assert (javahlBindings -> (j2sdk != null)); ((stdenv).mkDerivation { inherit expat httpServer javaSwigBindings javahlBindings localServer pythonBindings sslSupport; builder = /foo/bar; db4 = (if localServer then db4 else null); httpd = (if httpServer then httpd else null); j2sdk = (if javaSwigBindings then (swig).j2sdk else (if javahlBindings then j2sdk else null)); name = "subversion-1.1.1"; openssl = (if sslSupport then openssl else null); patches = (if javahlBindings then [ (/javahl.patch) ] else [ ]); python = (if pythonBindings then (swig).python else null); src = (fetchurl { md5 = "a180c3fe91680389c210c99def54d9e0"; url = "http://subversion.tigris.org/tarballs/subversion-1.1.1.tar.bz2"; }); swig = (if (pythonBindings || javaSwigBindings) then swig else null); }))
+({ db4 ? null, expat, fetchurl, httpServer ? false, httpd ? null, j2sdk ? null, javaSwigBindings ? false, javahlBindings ? false, localServer ? false, openssl ? null, pythonBindings ? false, sslSupport ? false, stdenv, swig ? null }: assert (expat != null); assert (localServer -> (db4 != null)); assert (httpServer -> ((httpd != null) && ((httpd).expat == expat))); assert (sslSupport -> ((openssl != null) && (httpServer -> ((httpd).openssl == openssl)))); assert (pythonBindings -> ((swig != null) && (swig).pythonSupport)); assert (javaSwigBindings -> ((swig != null) && (swig).javaSupport)); assert (javahlBindings -> (j2sdk != null)); ((stdenv).mkDerivation { inherit expat httpServer javaSwigBindings javahlBindings localServer pythonBindings sslSupport; builder = /foo/bar; db4 = (if localServer then db4 else null); httpd = (if httpServer then httpd else null); j2sdk = (if javaSwigBindings then (swig).j2sdk else (if javahlBindings then j2sdk else null)); name = "subversion-1.1.1"; openssl = (if sslSupport then openssl else null); patches = (if javahlBindings then [ (/javahl.patch) ] else [ ]); python = (if pythonBindings then (swig).python else null); src = (fetchurl { md5 = "a180c3fe91680389c210c99def54d9e0"; url = "http://subversion.tigris.org/tarballs/subversion-1.1.1.tar.bz2"; }); swig = (if (pythonBindings || javaSwigBindings) then swig else null); }))
diff --git a/tests/unit/libexpr/primops.cc b/tests/unit/libexpr/primops.cc
index 6d7649b3c..b1426edae 100644
--- a/tests/unit/libexpr/primops.cc
+++ b/tests/unit/libexpr/primops.cc
@@ -151,7 +151,7 @@ namespace nix {
     }
 
     TEST_F(PrimOpTest, unsafeGetAttrPos) {
-        state.corepkgsFS->addFile(CanonPath("foo.nix"), "{ y = \"x\"; }");
+        state.corepkgsFS->addFile(CanonPath("foo.nix"), "\n\r\n\r{ y = \"x\"; }");
 
         auto expr = "builtins.unsafeGetAttrPos \"y\" (import <nix/foo.nix>)";
         auto v = eval(expr);
@@ -165,10 +165,12 @@ namespace nix {
 
         auto line = v.attrs->find(createSymbol("line"));
         ASSERT_NE(line, nullptr);
-        ASSERT_THAT(*line->value, IsIntEq(1));
+        state.forceValue(*line->value, noPos);
+        ASSERT_THAT(*line->value, IsIntEq(4));
 
         auto column = v.attrs->find(createSymbol("column"));
         ASSERT_NE(column, nullptr);
+        state.forceValue(*column->value, noPos);
         ASSERT_THAT(*column->value, IsIntEq(3));
     }
 
diff --git a/tests/unit/libexpr/value/print.cc b/tests/unit/libexpr/value/print.cc
index aabf156c2..d2d699a64 100644
--- a/tests/unit/libexpr/value/print.cc
+++ b/tests/unit/libexpr/value/print.cc
@@ -110,8 +110,8 @@ TEST_F(ValuePrintingTests, vLambda)
         .up = nullptr,
         .values = { }
     };
-    PosTable::Origin origin((std::monostate()));
-    auto posIdx = state.positions.add(origin, 1, 1);
+    PosTable::Origin origin = state.positions.addOrigin(std::monostate(), 1);
+    auto posIdx = state.positions.add(origin, 0);
     auto body = ExprInt(0);
     auto formals = Formals {};
 
@@ -558,8 +558,8 @@ TEST_F(ValuePrintingTests, ansiColorsLambda)
         .up = nullptr,
         .values = { }
     };
-    PosTable::Origin origin((std::monostate()));
-    auto posIdx = state.positions.add(origin, 1, 1);
+    PosTable::Origin origin = state.positions.addOrigin(std::monostate(), 1);
+    auto posIdx = state.positions.add(origin, 0);
     auto body = ExprInt(0);
     auto formals = Formals {};