diff --git a/tests/functional/lang.sh b/tests/functional/lang.sh
index 8e6b472d3..3b0b52c17 100755
--- a/tests/functional/lang.sh
+++ b/tests/functional/lang.sh
@@ -47,8 +47,9 @@ for i in parse-fail-*.nix; do
     if test -e "$i.flags"; then
         read -r -a flags < "$i.flags"
     fi
-    if expectStderr 1 nix-instantiate --parse "${flags[@]}" - < "$i.nix" > "$i.err"
+    if expectStderr 1 nix-instantiate --parse "${flags[@]}" "$i.nix" > "$i.err"
     then
+        sed -i "s!$(pwd)!/pwd!g" "$i.err"
         diffAndAccept "$i" err err.exp
     else
         echo "FAIL: $i shouldn't parse"
@@ -65,11 +66,11 @@ for i in parse-okay-*.nix; do
         read -r -a flags < "$i.flags"
     fi
     if
-        expect 0 nix-instantiate --parse "${flags[@]}" - < "$i.nix" \
+        expect 0 nix-instantiate --parse "${flags[@]}" "$i.nix" \
             1> "$i.out" \
             2> "$i.err"
     then
-        sed "s!$(pwd)!/pwd!g" "$i.out" "$i.err"
+        sed -i "s!$(pwd)!/pwd!g" "$i.out" "$i.err"
         yq --in-place --yaml-output '.' "$i.out"
         diffAndAccept "$i" out exp
         diffAndAccept "$i" err err.exp
diff --git a/tests/functional/lang/parse-fail-crlf.err.exp b/tests/functional/lang/parse-fail-crlf.err.exp
index cf6c36c94..06c375774 100644
--- a/tests/functional/lang/parse-fail-crlf.err.exp
+++ b/tests/functional/lang/parse-fail-crlf.err.exp
@@ -1,11 +1,11 @@
 warning: CR (`\r`) and CRLF (`\r\n`) line endings are not supported. Please inspect the file and normalize it to use LF (`\n`) line endings instead. Use --extra-deprecated-features cr-line-endings to silence this warning.
-         at «stdin»:7:21:
+         at /pwd/parse-okay-crlf.nix:7:21:
               6|   x =
               7|   # Dit is een test.
                |                     ^
               8| y;
 error: CR (`\r`) and CRLF (`\r\n`) line endings are not supported. Please inspect the file and normalize it to use LF (`\n`) line endings instead. Use --extra-deprecated-features cr-line-endings to silence this warning.
-       at «stdin»:14:15:
+       at /pwd/parse-okay-crlf.nix:14:15:
            13|   # translated to LF.
            14|   foo = "multi
              |               ^
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 ffb5198c1..70fb226be 100644
--- a/tests/functional/lang/parse-fail-dup-attrs-1.err.exp
+++ b/tests/functional/lang/parse-fail-dup-attrs-1.err.exp
@@ -1,5 +1,5 @@
-error: attribute 'x' already defined at «stdin»:1:3
-       at «stdin»:3:3:
+error: attribute 'x' already defined at /pwd/parse-fail-dup-attrs-1.nix:1:3
+       at /pwd/parse-fail-dup-attrs-1.nix:3:3:
             2|   y = 456;
             3|   x = 789;
              |   ^
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 3105e60de..124284bc9 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 +1,5 @@
-error: attribute 'x' already defined at «stdin»:9:5
-       at «stdin»:10:18:
+error: attribute 'x' already defined at /pwd/parse-fail-dup-attrs-2.nix:9:5
+       at /pwd/parse-fail-dup-attrs-2.nix:10:18:
             9|     x = 789;
            10|     inherit (as) x;
              |                  ^
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 3105e60de..688ade4b8 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 +1,5 @@
-error: attribute 'x' already defined at «stdin»:9:5
-       at «stdin»:10:18:
+error: attribute 'x' already defined at /pwd/parse-fail-dup-attrs-3.nix:9:5
+       at /pwd/parse-fail-dup-attrs-3.nix:10:18:
             9|     x = 789;
            10|     inherit (as) x;
              |                  ^
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 c98a8f8d0..97acf214a 100644
--- a/tests/functional/lang/parse-fail-dup-attrs-4.err.exp
+++ b/tests/functional/lang/parse-fail-dup-attrs-4.err.exp
@@ -1,5 +1,5 @@
-error: attribute 'services.ssh.port' already defined at «stdin»:2:3
-       at «stdin»:3:3:
+error: attribute 'services.ssh.port' already defined at /pwd/parse-fail-dup-attrs-4.nix:2:3
+       at /pwd/parse-fail-dup-attrs-4.nix:3:3:
             2|   services.ssh.port = 22;
             3|   services.ssh.port = 23;
              |   ^
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 4e0a48eff..ae4a37ee8 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 +1,5 @@
-error: attribute 'x' already defined at «stdin»:6:13
-       at «stdin»:7:13:
+error: attribute 'x' already defined at /pwd/parse-fail-dup-attrs-7.nix:6:13
+       at /pwd/parse-fail-dup-attrs-7.nix:7:13:
             6|     inherit x;
             7|     inherit x;
              |             ^
diff --git a/tests/functional/lang/parse-fail-dup-formals.err.exp b/tests/functional/lang/parse-fail-dup-formals.err.exp
index d7c7e0237..9f6520e91 100644
--- a/tests/functional/lang/parse-fail-dup-formals.err.exp
+++ b/tests/functional/lang/parse-fail-dup-formals.err.exp
@@ -1,4 +1,4 @@
 error: duplicate formal function argument 'x'
-       at «stdin»:1:8:
+       at /pwd/parse-fail-dup-formals.nix:1:8:
             1| {x, y, x}: x
              |        ^
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 17f34b62d..24d5dec13 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»:3:6:
+       at /pwd/parse-fail-eof-in-string.nix: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
index fc56897e4..d21e5e7c0 100644
--- a/tests/functional/lang/parse-fail-eof-pos.err.exp
+++ b/tests/functional/lang/parse-fail-eof-pos.err.exp
@@ -1,5 +1,5 @@
 error: syntax error, unexpected end of file, expecting expression
-       at «stdin»:3:1:
+       at /pwd/parse-fail-eof-pos.nix:3:1:
             2| # no content
             3|
              | ^
diff --git a/tests/functional/lang/parse-fail-eol-1.err.exp b/tests/functional/lang/parse-fail-eol-1.err.exp
index f7f79b460..f500c357b 100644
--- a/tests/functional/lang/parse-fail-eol-1.err.exp
+++ b/tests/functional/lang/parse-fail-eol-1.err.exp
@@ -1,5 +1,5 @@
 error: undefined variable 'invalid'
-       at «stdin»:2:1:
+       at /pwd/parse-fail-eol-1.nix:2:1:
             1| # foo
             2| invalid
              | ^
diff --git a/tests/functional/lang/parse-fail-eol-2.err.exp b/tests/functional/lang/parse-fail-eol-2.err.exp
index f7f79b460..053865db2 100644
--- a/tests/functional/lang/parse-fail-eol-2.err.exp
+++ b/tests/functional/lang/parse-fail-eol-2.err.exp
@@ -1,5 +1,5 @@
 error: undefined variable 'invalid'
-       at «stdin»:2:1:
+       at /pwd/parse-fail-eol-2.nix:2:1:
             1| # foo
             2| invalid
              | ^
diff --git a/tests/functional/lang/parse-fail-eol-3.err.exp b/tests/functional/lang/parse-fail-eol-3.err.exp
index f7f79b460..06901baad 100644
--- a/tests/functional/lang/parse-fail-eol-3.err.exp
+++ b/tests/functional/lang/parse-fail-eol-3.err.exp
@@ -1,5 +1,5 @@
 error: undefined variable 'invalid'
-       at «stdin»:2:1:
+       at /pwd/parse-fail-eol-3.nix:2:1:
             1| # foo
             2| invalid
              | ^
diff --git a/tests/functional/lang/parse-fail-mixed-nested-attrs1.err.exp b/tests/functional/lang/parse-fail-mixed-nested-attrs1.err.exp
index a4472156b..6a0465f1a 100644
--- a/tests/functional/lang/parse-fail-mixed-nested-attrs1.err.exp
+++ b/tests/functional/lang/parse-fail-mixed-nested-attrs1.err.exp
@@ -1,5 +1,5 @@
-error: attribute 'z' already defined at «stdin»:3:16
-       at «stdin»:2:3:
+error: attribute 'z' already defined at /pwd/parse-fail-mixed-nested-attrs1.nix:3:16
+       at /pwd/parse-fail-mixed-nested-attrs1.nix:2:3:
             1| {
             2|   x.z = 3;
              |   ^
diff --git a/tests/functional/lang/parse-fail-mixed-nested-attrs2.err.exp b/tests/functional/lang/parse-fail-mixed-nested-attrs2.err.exp
index ead1f0dbd..f4d66a9cc 100644
--- a/tests/functional/lang/parse-fail-mixed-nested-attrs2.err.exp
+++ b/tests/functional/lang/parse-fail-mixed-nested-attrs2.err.exp
@@ -1,5 +1,5 @@
-error: attribute 'y' already defined at «stdin»:3:9
-       at «stdin»:2:3:
+error: attribute 'y' already defined at /pwd/parse-fail-mixed-nested-attrs2.nix:3:9
+       at /pwd/parse-fail-mixed-nested-attrs2.nix:2:3:
             1| {
             2|   x.y.y = 3;
              |   ^
diff --git a/tests/functional/lang/parse-fail-nul.err.exp b/tests/functional/lang/parse-fail-nul.err.exp
index a04ce99a8..b0f3eb3b8 100644
Binary files a/tests/functional/lang/parse-fail-nul.err.exp and b/tests/functional/lang/parse-fail-nul.err.exp differ
diff --git a/tests/functional/lang/parse-fail-path-slash.err.exp b/tests/functional/lang/parse-fail-path-slash.err.exp
index 0407543a1..769e685ac 100644
--- a/tests/functional/lang/parse-fail-path-slash.err.exp
+++ b/tests/functional/lang/parse-fail-path-slash.err.exp
@@ -1,5 +1,5 @@
 error: path has a trailing slash
-       at «stdin»:6:12:
+       at /pwd/parse-fail-path-slash.nix:6:12:
             5| # and https://nixos.org/nix-dev/2016-June/020829.html
             6| /nix/store/
              |            ^
diff --git a/tests/functional/lang/parse-fail-patterns-1.err.exp b/tests/functional/lang/parse-fail-patterns-1.err.exp
index 6ba39d884..9278c6af6 100644
--- a/tests/functional/lang/parse-fail-patterns-1.err.exp
+++ b/tests/functional/lang/parse-fail-patterns-1.err.exp
@@ -1,5 +1,5 @@
 error: duplicate formal function argument 'args'
-       at «stdin»:1:1:
+       at /pwd/parse-fail-patterns-1.nix:1:1:
             1| args@{args, x, y, z}: x
              | ^
             2|
diff --git a/tests/functional/lang/parse-fail-regression-20060610.err.exp b/tests/functional/lang/parse-fail-regression-20060610.err.exp
index 59fa1f08f..871bf9517 100644
--- a/tests/functional/lang/parse-fail-regression-20060610.err.exp
+++ b/tests/functional/lang/parse-fail-regression-20060610.err.exp
@@ -1,5 +1,5 @@
 error: undefined variable 'gcc'
-       at «stdin»:9:11:
+       at /pwd/parse-fail-regression-20060610.nix:9:11:
             8| ({
             9|   inherit gcc;
              |           ^
diff --git a/tests/functional/lang/parse-fail-set.err.exp b/tests/functional/lang/parse-fail-set.err.exp
index 2f77406a7..f9b1d9e90 100644
--- a/tests/functional/lang/parse-fail-set.err.exp
+++ b/tests/functional/lang/parse-fail-set.err.exp
@@ -1,5 +1,5 @@
 error: undefined variable 'x'
-       at «stdin»:1:3:
+       at /pwd/parse-fail-set.nix:1:3:
             1| 8.x
              |   ^
             2|
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 d1728f125..036d0f1f7 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 +1,5 @@
 error: syntax error, expecting '}'
-       at «stdin»:3:13:
+       at /pwd/parse-fail-undef-var-2.nix:3:13:
             2|
             3|   f = {x, y : ["baz" "bar" z "bat"]}: x + y;
              |             ^
diff --git a/tests/functional/lang/parse-fail-undef-var.err.exp b/tests/functional/lang/parse-fail-undef-var.err.exp
index 3d143d9af..38b8fd5cb 100644
--- a/tests/functional/lang/parse-fail-undef-var.err.exp
+++ b/tests/functional/lang/parse-fail-undef-var.err.exp
@@ -1,5 +1,5 @@
 error: undefined variable 'y'
-       at «stdin»:1:4:
+       at /pwd/parse-fail-undef-var.nix:1:4:
             1| x: y
              |    ^
             2|
diff --git a/tests/functional/lang/parse-fail-utf8.err.exp b/tests/functional/lang/parse-fail-utf8.err.exp
index 81df9dc8a..7a134cfd4 100644
--- a/tests/functional/lang/parse-fail-utf8.err.exp
+++ b/tests/functional/lang/parse-fail-utf8.err.exp
@@ -1,5 +1,5 @@
 error: syntax error, expecting end of file
-       at «stdin»:1:5:
+       at /pwd/parse-fail-utf8.nix:1:5:
             1| 123 é 4
              |     ^
             2|
diff --git a/tests/functional/lang/parse-okay-rec-set-override-warning.err.exp b/tests/functional/lang/parse-okay-rec-set-override-warning.err.exp
index 6b55c567f..5e043d404 100644
--- a/tests/functional/lang/parse-okay-rec-set-override-warning.err.exp
+++ b/tests/functional/lang/parse-okay-rec-set-override-warning.err.exp
@@ -1,11 +1,11 @@
 warning: __overrides attributes are deprecated and will be removed in the future. Use --extra-deprecated-features rec-set-overrides to silence this warning.
-         at «stdin»:3:17:
+         at /pwd/parse-okay-rec-set-override-warning.nix:3:17:
               2|   # Should warn
               3|   { a = rec {}; a.__overrides = {}; }
                |                 ^
               4|   rec { __overrides = {}; }
 warning: __overrides attributes are deprecated and will be removed in the future. Use --extra-deprecated-features rec-set-overrides to silence this warning.
-         at «stdin»:4:9:
+         at /pwd/parse-okay-rec-set-override-warning.nix:4:9:
               3|   { a = rec {}; a.__overrides = {}; }
               4|   rec { __overrides = {}; }
                |         ^