diff --git a/cue/testdata/basicrewrite/001_regexp.txtar b/cue/testdata/basicrewrite/001_regexp.txtar
index 0381a5f..8de10e6 100644
--- a/cue/testdata/basicrewrite/001_regexp.txtar
+++ b/cue/testdata/basicrewrite/001_regexp.txtar
@@ -74,8 +74,10 @@
     ./in.cue:11:5
 e1: cannot use 1 (type int) as type (string|bytes):
     ./in.cue:20:5
+    ./in.cue:20:14
 e2: cannot use true (type bool) as type (string|bytes):
     ./in.cue:21:5
+    ./in.cue:21:14
 
 Result:
 (_|_){
@@ -99,10 +101,12 @@
   e1: (_|_){
     // [eval] e1: cannot use 1 (type int) as type (string|bytes):
     //     ./in.cue:20:5
+    //     ./in.cue:20:14
   }
   e2: (_|_){
     // [eval] e2: cannot use true (type bool) as type (string|bytes):
     //     ./in.cue:21:5
+    //     ./in.cue:21:14
   }
   e3: (_|_){
     // [eval] e3: conflicting values !="a" and <5 (mismatched types string and number):
diff --git a/cue/testdata/basicrewrite/002_arithmetic.txtar b/cue/testdata/basicrewrite/002_arithmetic.txtar
index 21d4cfb..2286250 100644
--- a/cue/testdata/basicrewrite/002_arithmetic.txtar
+++ b/cue/testdata/basicrewrite/002_arithmetic.txtar
@@ -109,14 +109,19 @@
     ./in.cue:16:9
 e0: invalid operands 2 and "a" to '+' (type int and string):
     ./in.cue:23:5
+    ./in.cue:23:9
 e5: invalid operands 1.0 and 2 to 'div' (type float and int):
     ./in.cue:29:5
+    ./in.cue:29:13
 e6: invalid operands 2 and 2.0 to 'rem' (type int and float):
     ./in.cue:30:5
+    ./in.cue:30:11
 e7: invalid operands 2 and 2.0 to 'quo' (type int and float):
     ./in.cue:31:5
+    ./in.cue:31:11
 e8: invalid operands 1.0 and 1 to 'mod' (type float and int):
     ./in.cue:32:5
+    ./in.cue:32:13
 
 Result:
 (_|_){
@@ -160,21 +165,26 @@
   e0: (_|_){
     // [eval] e0: invalid operands 2 and "a" to '+' (type int and string):
     //     ./in.cue:23:5
+    //     ./in.cue:23:9
   }
   e5: (_|_){
     // [eval] e5: invalid operands 1.0 and 2 to 'div' (type float and int):
     //     ./in.cue:29:5
+    //     ./in.cue:29:13
   }
   e6: (_|_){
     // [eval] e6: invalid operands 2 and 2.0 to 'rem' (type int and float):
     //     ./in.cue:30:5
+    //     ./in.cue:30:11
   }
   e7: (_|_){
     // [eval] e7: invalid operands 2 and 2.0 to 'quo' (type int and float):
     //     ./in.cue:31:5
+    //     ./in.cue:31:11
   }
   e8: (_|_){
     // [eval] e8: invalid operands 1.0 and 1 to 'mod' (type float and int):
     //     ./in.cue:32:5
+    //     ./in.cue:32:13
   }
 }
diff --git a/cue/testdata/basicrewrite/003_integer-specific_arithmetic.txtar b/cue/testdata/basicrewrite/003_integer-specific_arithmetic.txtar
index 742b92a..0ed6240 100644
--- a/cue/testdata/basicrewrite/003_integer-specific_arithmetic.txtar
+++ b/cue/testdata/basicrewrite/003_integer-specific_arithmetic.txtar
@@ -89,20 +89,28 @@
 Errors:
 qe1: invalid operands 2.0 and 1 to 'quo' (type float and int):
     ./in.cue:5:6
+    ./in.cue:5:14
 qe2: invalid operands 2 and 1.0 to 'quo' (type int and float):
     ./in.cue:6:6
+    ./in.cue:6:12
 re1: invalid operands 2.0 and 1 to 'rem' (type float and int):
     ./in.cue:12:6
+    ./in.cue:12:14
 re2: invalid operands 2 and 1.0 to 'rem' (type int and float):
     ./in.cue:13:6
+    ./in.cue:13:12
 de1: invalid operands 2.0 and 1 to 'div' (type float and int):
     ./in.cue:19:6
+    ./in.cue:19:14
 de2: invalid operands 2 and 1.0 to 'div' (type int and float):
     ./in.cue:20:6
+    ./in.cue:20:12
 me1: invalid operands 2.0 and 1 to 'mod' (type float and int):
     ./in.cue:26:6
+    ./in.cue:26:14
 me2: invalid operands 2 and 1.0 to 'mod' (type int and float):
     ./in.cue:27:6
+    ./in.cue:27:12
 
 Result:
 (_|_){
@@ -114,10 +122,12 @@
   qe1: (_|_){
     // [eval] qe1: invalid operands 2.0 and 1 to 'quo' (type float and int):
     //     ./in.cue:5:6
+    //     ./in.cue:5:14
   }
   qe2: (_|_){
     // [eval] qe2: invalid operands 2 and 1.0 to 'quo' (type int and float):
     //     ./in.cue:6:6
+    //     ./in.cue:6:12
   }
   r1: (int){ 1 }
   r2: (int){ 1 }
@@ -126,10 +136,12 @@
   re1: (_|_){
     // [eval] re1: invalid operands 2.0 and 1 to 'rem' (type float and int):
     //     ./in.cue:12:6
+    //     ./in.cue:12:14
   }
   re2: (_|_){
     // [eval] re2: invalid operands 2 and 1.0 to 'rem' (type int and float):
     //     ./in.cue:13:6
+    //     ./in.cue:13:12
   }
   d1: (int){ 2 }
   d2: (int){ -2 }
@@ -138,10 +150,12 @@
   de1: (_|_){
     // [eval] de1: invalid operands 2.0 and 1 to 'div' (type float and int):
     //     ./in.cue:19:6
+    //     ./in.cue:19:14
   }
   de2: (_|_){
     // [eval] de2: invalid operands 2 and 1.0 to 'div' (type int and float):
     //     ./in.cue:20:6
+    //     ./in.cue:20:12
   }
   m1: (int){ 1 }
   m2: (int){ 1 }
@@ -150,9 +164,11 @@
   me1: (_|_){
     // [eval] me1: invalid operands 2.0 and 1 to 'mod' (type float and int):
     //     ./in.cue:26:6
+    //     ./in.cue:26:14
   }
   me2: (_|_){
     // [eval] me2: invalid operands 2 and 1.0 to 'mod' (type int and float):
     //     ./in.cue:27:6
+    //     ./in.cue:27:12
   }
 }
diff --git a/cue/testdata/basicrewrite/007_strings_and_bytes.txtar b/cue/testdata/basicrewrite/007_strings_and_bytes.txtar
index 27383f7..a1ffb65 100644
--- a/cue/testdata/basicrewrite/007_strings_and_bytes.txtar
+++ b/cue/testdata/basicrewrite/007_strings_and_bytes.txtar
@@ -43,8 +43,10 @@
 Errors:
 e0: invalid operands "a" and '' to '+' (type string and bytes):
     ./in.cue:10:5
+    ./in.cue:10:11
 e1: invalid operands 'b' and "c" to '+' (type bytes and string):
     ./in.cue:11:5
+    ./in.cue:11:11
 
 Result:
 (_|_){
@@ -58,9 +60,11 @@
   e0: (_|_){
     // [eval] e0: invalid operands "a" and '' to '+' (type string and bytes):
     //     ./in.cue:10:5
+    //     ./in.cue:10:11
   }
   e1: (_|_){
     // [eval] e1: invalid operands 'b' and "c" to '+' (type bytes and string):
     //     ./in.cue:11:5
+    //     ./in.cue:11:11
   }
 }
diff --git a/cue/testdata/basicrewrite/010_lists.txtar b/cue/testdata/basicrewrite/010_lists.txtar
index 9f65dc6..e6f90cd 100644
--- a/cue/testdata/basicrewrite/010_lists.txtar
+++ b/cue/testdata/basicrewrite/010_lists.txtar
@@ -83,6 +83,7 @@
     ./in.cue:5:12
 e3: invalid index -1 (index must be non-negative):
     ./in.cue:6:8
+    ./in.cue:6:12
 e4.3: invalid value 8 (out of bound <=5):
     ./in.cue:7:24
     ./in.cue:7:41
@@ -116,6 +117,7 @@
   e3: (_|_){
     // [eval] e3: invalid index -1 (index must be non-negative):
     //     ./in.cue:6:8
+    //     ./in.cue:6:12
   }
   e4: (_|_){
     // [eval]
diff --git a/cue/testdata/basicrewrite/015_types.txtar b/cue/testdata/basicrewrite/015_types.txtar
index 1616b60..0e79e4a 100644
--- a/cue/testdata/basicrewrite/015_types.txtar
+++ b/cue/testdata/basicrewrite/015_types.txtar
@@ -39,14 +39,14 @@
 }
 -- out/eval --
 Errors:
+b: invalid operand int ('!' requires concrete value):
+    ./in.cue:7:6
 e: conflicting values int and string (mismatched types int and string):
     ./in.cue:5:5
     ./in.cue:5:11
 e2: conflicting values 1 and string (mismatched types int and string):
     ./in.cue:6:5
     ./in.cue:6:9
-b: invalid operand int ('!' requires concrete value):
-    ./in.cue:7:5
 p: invalid operation +true (+ bool):
     ./in.cue:8:5
 m: invalid operation -false (- bool):
@@ -71,7 +71,7 @@
   }
   b: (_|_){
     // [eval] b: invalid operand int ('!' requires concrete value):
-    //     ./in.cue:7:5
+    //     ./in.cue:7:6
   }
   p: (_|_){
     // [eval] p: invalid operation +true (+ bool):
diff --git a/cue/testdata/basicrewrite/016_comparison.txtar b/cue/testdata/basicrewrite/016_comparison.txtar
index 11ef3b3..686c4c1 100644
--- a/cue/testdata/basicrewrite/016_comparison.txtar
+++ b/cue/testdata/basicrewrite/016_comparison.txtar
@@ -40,6 +40,7 @@
 Errors:
 err: invalid operands 2 and "s" to '==' (type int and string):
     ./in.cue:9:6
+    ./in.cue:9:11
 
 Result:
 (_|_){
@@ -54,5 +55,6 @@
   err: (_|_){
     // [eval] err: invalid operands 2 and "s" to '==' (type int and string):
     //     ./in.cue:9:6
+    //     ./in.cue:9:11
   }
 }
diff --git a/cue/testdata/builtins/all.txtar b/cue/testdata/builtins/all.txtar
index b6c5c20..4b9cb62 100644
--- a/cue/testdata/builtins/all.txtar
+++ b/cue/testdata/builtins/all.txtar
@@ -22,6 +22,7 @@
 Errors:
 fatalArg.x: invalid operands "eee" and 'eee' to '+' (type string and bytes):
     ./in.cue:3:12
+    ./in.cue:3:20
 0.a: undefined field c:
     ./in.cue:9:20
 
@@ -33,6 +34,7 @@
     x: (_|_){
       // [eval] fatalArg.x: invalid operands "eee" and 'eee' to '+' (type string and bytes):
       //     ./in.cue:3:12
+      //     ./in.cue:3:20
     }
   }
   fatalChild: (_|_){
diff --git a/cue/testdata/builtins/incomplete.txtar b/cue/testdata/builtins/incomplete.txtar
index 3d3eea9..85765b6 100644
--- a/cue/testdata/builtins/incomplete.txtar
+++ b/cue/testdata/builtins/incomplete.txtar
@@ -95,6 +95,7 @@
     ./in.cue:77:8
 badListError.x: invalid operands 2 and "foo" to '+' (type int and string):
     ./in.cue:83:8
+    ./in.cue:84:8
 
 Result:
 (_|_){
@@ -194,10 +195,12 @@
       transformed: (_|_){
         // [incomplete] incompleteArgStringList.#a.transformed: non-concrete value string in operand to +:
         //     ./in.cue:58:22
+        //     ./in.cue:57:9
       }
       joined: (_|_){
         // [incomplete] 0: non-concrete value string in operand to +:
         //     ./in.cue:58:22
+        //     ./in.cue:57:9
       }
     }
   }
@@ -216,15 +219,18 @@
     x: (_|_){
       // [incomplete] incompleteListError.x: non-concrete value _ in operand to +:
       //     ./in.cue:70:8
+      //     ./in.cue:71:5
     }
     y: (_){ _ }
     decimal: (_|_){
       // [incomplete] incompleteListError.x: non-concrete value _ in operand to +:
       //     ./in.cue:70:8
+      //     ./in.cue:71:5
     }
     str: (_|_){
       // [incomplete] incompleteListError.x: non-concrete value _ in operand to +:
       //     ./in.cue:70:8
+      //     ./in.cue:71:5
     }
   }
   badListType: (_|_){
@@ -244,15 +250,18 @@
     x: (_|_){
       // [eval] badListError.x: invalid operands 2 and "foo" to '+' (type int and string):
       //     ./in.cue:83:8
+      //     ./in.cue:84:8
     }
     y: (string){ "foo" }
     decimal: (_|_){
       // [eval] badListError.x: invalid operands 2 and "foo" to '+' (type int and string):
       //     ./in.cue:83:8
+      //     ./in.cue:84:8
     }
     str: (_|_){
       // [eval] badListError.x: invalid operands 2 and "foo" to '+' (type int and string):
       //     ./in.cue:83:8
+      //     ./in.cue:84:8
     }
   }
 }
diff --git a/cue/testdata/builtins/issue299.txtar b/cue/testdata/builtins/issue299.txtar
index d6d66ce..104f4dd 100644
--- a/cue/testdata/builtins/issue299.txtar
+++ b/cue/testdata/builtins/issue299.txtar
@@ -5,13 +5,19 @@
 x: ["x","x"]
 -- out/eval --
 Errors:
-x: invalid value ["x","x"] (does not satisfy list.UniqueItems)
+x: invalid value ["x","x"] (does not satisfy list.UniqueItems):
+    ./in.cue:2:1
+    ./in.cue:3:1
+    ./in.cue:4:1
 
 Result:
 (_|_){
   // [eval]
   x: (_|_){
-    // [eval] x: invalid value ["x","x"] (does not satisfy list.UniqueItems)
+    // [eval] x: invalid value ["x","x"] (does not satisfy list.UniqueItems):
+    //     ./in.cue:2:1
+    //     ./in.cue:3:1
+    //     ./in.cue:4:1
     0: (string){ "x" }
     1: (string){ "x" }
   }
diff --git a/cue/testdata/builtins/validators.txtar b/cue/testdata/builtins/validators.txtar
index 541297b..aa0ae60 100644
--- a/cue/testdata/builtins/validators.txtar
+++ b/cue/testdata/builtins/validators.txtar
@@ -125,6 +125,8 @@
       kv: (_|_){
         // [incomplete] incompleteError2.MyType.kv: invalid value {} (does not satisfy struct.MinFields(1)): len(fields) < MinFields(1) (0 < 1):
         //     ./in.cue:22:17
+        //     ./in.cue:21:13
+        //     ./in.cue:22:13
         //     ./in.cue:22:34
       }
     }
@@ -148,6 +150,8 @@
       kv: (_|_){
         // [incomplete] violation.#MyType.kv: invalid value {} (does not satisfy struct.MinFields(1)): len(fields) < MinFields(1) (0 < 1):
         //     ./in.cue:49:17
+        //     ./in.cue:48:13
+        //     ./in.cue:49:13
         //     ./in.cue:49:34
       }
     }
diff --git a/cue/testdata/comprehensions/errors.txtar b/cue/testdata/comprehensions/errors.txtar
index 85fa787..6262163 100644
--- a/cue/testdata/comprehensions/errors.txtar
+++ b/cue/testdata/comprehensions/errors.txtar
@@ -48,6 +48,7 @@
   userError: (_|_){
     // [incomplete] userError: non-concrete value string in operand to !=:
     //     ./in.cue:21:8
+    //     ./in.cue:20:5
     a: (string){ string }
   }
 }
diff --git a/cue/testdata/comprehensions/iferror.txtar b/cue/testdata/comprehensions/iferror.txtar
index ee6ee4d..ced1064 100644
--- a/cue/testdata/comprehensions/iferror.txtar
+++ b/cue/testdata/comprehensions/iferror.txtar
@@ -114,6 +114,7 @@
 Errors:
 wrongConcreteType: cannot use 2 (type int) as type bool:
     ./in.cue:4:2
+    ./in.cue:1:9
 wrongType: cannot use int (type int) as type bool:
     ./in.cue:10:2
 
@@ -127,6 +128,7 @@
   wrongConcreteType: (_|_){
     // [eval] wrongConcreteType: cannot use 2 (type int) as type bool:
     //     ./in.cue:4:2
+    //     ./in.cue:1:9
   }
   wrongType: (_|_){
     // [eval] wrongType: cannot use int (type int) as type bool:
diff --git a/cue/testdata/cycle/023_reentrance.txtar b/cue/testdata/cycle/023_reentrance.txtar
index a063692..628cb26 100644
--- a/cue/testdata/cycle/023_reentrance.txtar
+++ b/cue/testdata/cycle/023_reentrance.txtar
@@ -91,15 +91,21 @@
     out: (_|_){
       // [incomplete] non-concrete value int in operand to >=:
       //     ./in.cue:7:5
+      //     ./in.cue:3:32
+      //     ./in.cue:5:2
       // non-concrete value int in operand to <:
       //     ./in.cue:10:5
+      //     ./in.cue:3:32
+      //     ./in.cue:5:2
     }
   }
   fib: (_|_){
     // [incomplete] fib: non-concrete value int in operand to >=:
     //     ./in.cue:7:5
+    //     ./in.cue:5:2
     // fib: non-concrete value int in operand to <:
     //     ./in.cue:10:5
+    //     ./in.cue:5:2
     n: (int){ int }
   }
   fib2: (int){ 1 }
diff --git a/cue/testdata/disjunctions/elimination.txtar b/cue/testdata/disjunctions/elimination.txtar
index 9b7ebf7..73dc032 100644
--- a/cue/testdata/disjunctions/elimination.txtar
+++ b/cue/testdata/disjunctions/elimination.txtar
@@ -264,7 +264,9 @@
                 a: (_|_){
                   // [incomplete] nestedNonMonotonic.incomplete.a.n1.p1.x.a: invalid value {c:1} (does not satisfy struct.MinFields(2)): len(fields) < MinFields(2) (1 < 2):
                   //     ./in.cue:84:13
+                  //     ./in.cue:84:10
                   //     ./in.cue:84:30
+                  //     ./in.cue:85:10
                   c: (int){ 1 }
                 }
               }, (null){ null }) }
@@ -274,6 +276,8 @@
                 a: (_|_){
                   // [incomplete] nestedNonMonotonic.incomplete.a.n1.p2.x.a: invalid value {c:1} (does not satisfy struct.MinFields(2)): len(fields) < MinFields(2) (1 < 2):
                   //     ./in.cue:90:13
+                  //     ./in.cue:89:10
+                  //     ./in.cue:90:10
                   //     ./in.cue:90:30
                   c: (int){ 1 }
                 }
@@ -287,7 +291,9 @@
                   b: (_|_){
                     // [incomplete] nestedNonMonotonic.incomplete.a.n2.p1.x.a.b: invalid value {c:1} (does not satisfy struct.MinFields(2)): len(fields) < MinFields(2) (1 < 2):
                     //     ./in.cue:94:16
+                    //     ./in.cue:94:13
                     //     ./in.cue:94:33
+                    //     ./in.cue:95:13
                     c: (int){ 1 }
                   }
                 }
@@ -299,6 +305,8 @@
                   b: (_|_){
                     // [incomplete] nestedNonMonotonic.incomplete.a.n2.p2.x.a.b: invalid value {c:1} (does not satisfy struct.MinFields(2)): len(fields) < MinFields(2) (1 < 2):
                     //     ./in.cue:100:16
+                    //     ./in.cue:99:13
+                    //     ./in.cue:100:13
                     //     ./in.cue:100:33
                     c: (int){ 1 }
                   }
@@ -314,7 +322,10 @@
                 a: (_|_){
                   // [incomplete] nestedNonMonotonic.incomplete.b.n1.p1.x.a: invalid value {c:1,d:1} (does not satisfy struct.MinFields(3)): len(fields) < MinFields(3) (2 < 3):
                   //     ./in.cue:105:13
+                  //     ./in.cue:105:10
                   //     ./in.cue:105:30
+                  //     ./in.cue:106:10
+                  //     ./in.cue:107:10
                   c: (int){ 1 }
                   d: (int){ 1 }
                 }
@@ -325,7 +336,10 @@
                 a: (_|_){
                   // [incomplete] nestedNonMonotonic.incomplete.b.n1.p2.x.a: invalid value {c:1,d:1} (does not satisfy struct.MinFields(3)): len(fields) < MinFields(3) (2 < 3):
                   //     ./in.cue:112:13
+                  //     ./in.cue:111:10
+                  //     ./in.cue:112:10
                   //     ./in.cue:112:30
+                  //     ./in.cue:113:10
                   c: (int){ 1 }
                   d: (int){ 1 }
                 }
@@ -336,6 +350,9 @@
                 a: (_|_){
                   // [incomplete] nestedNonMonotonic.incomplete.b.n1.p3.x.a: invalid value {c:1,d:1} (does not satisfy struct.MinFields(3)): len(fields) < MinFields(3) (2 < 3):
                   //     ./in.cue:119:13
+                  //     ./in.cue:117:10
+                  //     ./in.cue:118:10
+                  //     ./in.cue:119:10
                   //     ./in.cue:119:30
                   c: (int){ 1 }
                   d: (int){ 1 }
@@ -350,6 +367,15 @@
                   b: (_|_){
                     // [incomplete] nestedNonMonotonic.incomplete.b.n2.p1.x.a.b: invalid value {c:1,d:1} (does not satisfy struct.MinFields(3)): len(fields) < MinFields(3) (2 < 3):
                     //     ./in.cue:137:16
+                    //     ./in.cue:123:13
+                    //     ./in.cue:124:13
+                    //     ./in.cue:125:13
+                    //     ./in.cue:129:13
+                    //     ./in.cue:130:13
+                    //     ./in.cue:131:13
+                    //     ./in.cue:135:13
+                    //     ./in.cue:136:13
+                    //     ./in.cue:137:13
                     //     ./in.cue:137:33
                     c: (int){ 1 }
                     d: (int){ 1 }
diff --git a/cue/testdata/disjunctions/errors.txtar b/cue/testdata/disjunctions/errors.txtar
index 1a1ba71..cddde7f 100644
--- a/cue/testdata/disjunctions/errors.txtar
+++ b/cue/testdata/disjunctions/errors.txtar
@@ -126,6 +126,7 @@
   explicitDefaultError: (_|_){
     // [incomplete] explicitDefaultError: non-concrete value string in operand to !=:
     //     ./in.cue:30:8
+    //     ./in.cue:28:5
     a: (string){ string }
   }
 }
diff --git a/cue/testdata/eval/bounds.txtar b/cue/testdata/eval/bounds.txtar
index 45fa97b..7607f88 100644
--- a/cue/testdata/eval/bounds.txtar
+++ b/cue/testdata/eval/bounds.txtar
@@ -119,27 +119,27 @@
     basic5: (bytes){ bytes }
     bne1: (_|_){
       // [incomplete] simplifyExpr.bne1: non-concrete value s for bound !=:
-      //     ./in.cue:55:11
+      //     ./in.cue:55:14
     }
     bne2: (_|_){
       // [incomplete] simplifyExpr.bne2: non-concrete value n for bound !=:
-      //     ./in.cue:56:11
+      //     ./in.cue:56:14
     }
     bne3: (_|_){
       // [incomplete] simplifyExpr.bne3: non-concrete value n for bound !=:
-      //     ./in.cue:57:11
+      //     ./in.cue:57:14
     }
     bne4: (_|_){
       // [incomplete] simplifyExpr.bne4: non-concrete value i for bound !=:
-      //     ./in.cue:58:11
+      //     ./in.cue:58:14
     }
     bne5: (_|_){
       // [incomplete] simplifyExpr.bne5: non-concrete value b for bound !=:
-      //     ./in.cue:59:11
+      //     ./in.cue:59:14
     }
     e1: (_|_){
       // [incomplete] simplifyExpr.e1: non-concrete value =~"foo" for bound <:
-      //     ./in.cue:61:9
+      //     ./in.cue:61:11
     }
     e2: (_|_){
       // [eval] simplifyExpr.e2: cannot use null for bound >:
diff --git a/cue/testdata/eval/incomplete.txtar b/cue/testdata/eval/incomplete.txtar
index c075991..6509e3f 100644
--- a/cue/testdata/eval/incomplete.txtar
+++ b/cue/testdata/eval/incomplete.txtar
@@ -24,6 +24,7 @@
   e1: (_|_){
     // [incomplete] e1: non-concrete value string in operand to +:
     //     ./in.cue:3:5
+    //     ./in.cue:1:1
   }
   e2: (string){ >"bar" }
   e3: (string){ "foo" }
@@ -31,6 +32,7 @@
   e4: (_|_){
     // [incomplete] e1: non-concrete value string in operand to +:
     //     ./in.cue:3:5
+    //     ./in.cue:1:1
   }
   e5: (_|_){
     // [cycle] cycle error
@@ -55,6 +57,7 @@
   okay: (_|_){
     // [incomplete] okay: non-concrete value >10 & int in operand to +:
     //     ./in.cue:18:7
+    //     ./in.cue:18:8
   }
 }
 -- out/compile --
diff --git a/cue/testdata/eval/resolve_basic.txtar b/cue/testdata/eval/resolve_basic.txtar
index 08be88e..0fc38bc 100644
--- a/cue/testdata/eval/resolve_basic.txtar
+++ b/cue/testdata/eval/resolve_basic.txtar
@@ -18,6 +18,7 @@
     y: (_|_){
       // [incomplete] d.y: non-concrete value _ in operand to +:
       //     ./in.cue:5:6
+      //     ./in.cue:4:3
     }
   }
   e: (struct){
diff --git a/cue/testdata/eval/selectors.txtar b/cue/testdata/eval/selectors.txtar
index 4fdc64e..cb0b141 100644
--- a/cue/testdata/eval/selectors.txtar
+++ b/cue/testdata/eval/selectors.txtar
@@ -25,6 +25,7 @@
     y: (_|_){
       // [incomplete] d.y: non-concrete value _ in operand to +:
       //     ./in.cue:5:6
+      //     ./in.cue:4:3
     }
   }
   e: (struct){
diff --git a/cue/testdata/fulleval/005_conditional_field.txtar b/cue/testdata/fulleval/005_conditional_field.txtar
index 5aeea2c..dd8943a 100644
--- a/cue/testdata/fulleval/005_conditional_field.txtar
+++ b/cue/testdata/fulleval/005_conditional_field.txtar
@@ -63,6 +63,7 @@
   d: (_|_){
     // [incomplete] d: non-concrete value int in operand to >:
     //     ./in.cue:14:5
+    //     ./in.cue:13:2
     a: (int){ int }
   }
   a: (string){ "foo" }
diff --git a/cue/testdata/fulleval/018_recursive_evaluation_within_list.txtar b/cue/testdata/fulleval/018_recursive_evaluation_within_list.txtar
index 79d2de4..9d0ca73 100644
--- a/cue/testdata/fulleval/018_recursive_evaluation_within_list.txtar
+++ b/cue/testdata/fulleval/018_recursive_evaluation_within_list.txtar
@@ -88,6 +88,7 @@
     d: (_|_){
       // [incomplete] b1.d: non-concrete value string in operand to +:
       //     ./in.cue:10:5
+      //     ./in.cue:11:2
     }
     c: (string){ string }
   }
diff --git a/cue/testdata/fulleval/020_complex_interaction_of_groundness.txtar b/cue/testdata/fulleval/020_complex_interaction_of_groundness.txtar
index 1b31de5..e0b4379 100644
--- a/cue/testdata/fulleval/020_complex_interaction_of_groundness.txtar
+++ b/cue/testdata/fulleval/020_complex_interaction_of_groundness.txtar
@@ -74,6 +74,8 @@
         s: (_|_){
           // [incomplete] a.b.c.s: non-concrete value string in operand to +:
           //     ./in.cue:4:34
+          //     ./in.cue:4:20
+          //     ./in.cue:5:10
         }
       }
     }
diff --git a/cue/testdata/fulleval/021_complex_groundness_2.txtar b/cue/testdata/fulleval/021_complex_groundness_2.txtar
index 50a9f11..582df99 100644
--- a/cue/testdata/fulleval/021_complex_groundness_2.txtar
+++ b/cue/testdata/fulleval/021_complex_groundness_2.txtar
@@ -85,8 +85,16 @@
       s: (_|_){
         // [incomplete] f1.res.s: non-concrete value string in operand to +:
         //     ./in.cue:5:25
+        //     ./in.cue:3:31
+        //     ./in.cue:5:11
+        //     ./in.cue:6:20
+        //     ./in.cue:7:10
         // f1.res.s: non-concrete value string in operand to +:
         //     ./in.cue:6:34
+        //     ./in.cue:3:31
+        //     ./in.cue:5:11
+        //     ./in.cue:6:20
+        //     ./in.cue:7:10
       }
     }
   }
@@ -97,8 +105,14 @@
         s: (_|_){
           // [incomplete] a.b.c.s: non-concrete value string in operand to +:
           //     ./in.cue:5:25
+          //     ./in.cue:5:11
+          //     ./in.cue:6:20
+          //     ./in.cue:7:10
           // a.b.c.s: non-concrete value string in operand to +:
           //     ./in.cue:6:34
+          //     ./in.cue:5:11
+          //     ./in.cue:6:20
+          //     ./in.cue:7:10
         }
       }
     }
diff --git a/cue/testdata/fulleval/026_dont_convert_incomplete_errors_to_non-incomplete.txtar b/cue/testdata/fulleval/026_dont_convert_incomplete_errors_to_non-incomplete.txtar
index 150c352..ec3b2c0 100644
--- a/cue/testdata/fulleval/026_dont_convert_incomplete_errors_to_non-incomplete.txtar
+++ b/cue/testdata/fulleval/026_dont_convert_incomplete_errors_to_non-incomplete.txtar
@@ -65,18 +65,22 @@
   n4: (_|_){
     // [incomplete] n4: non-concrete value <4 in operand to +:
     //     ./in.cue:6:5
+    //     ./in.cue:18:6
   }
   n5: (_|_){
     // [incomplete] n5: non-concrete value <4 in operand to -:
     //     ./in.cue:7:5
+    //     ./in.cue:18:6
   }
   n6: (_|_){
     // [incomplete] n6: non-concrete value <4 in operand to *:
     //     ./in.cue:8:5
+    //     ./in.cue:18:6
   }
   n7: (_|_){
     // [incomplete] n7: non-concrete value <4 in operand to /:
     //     ./in.cue:9:5
+    //     ./in.cue:18:6
   }
   b1: (_|_){
     // [incomplete] b1: operand is of '!' not concrete (was bool):
diff --git a/cue/testdata/references/incomplete.txtar b/cue/testdata/references/incomplete.txtar
index e790969..b316a99 100644
--- a/cue/testdata/references/incomplete.txtar
+++ b/cue/testdata/references/incomplete.txtar
@@ -34,6 +34,7 @@
 Errors:
 incompleteIndex.a: invalid index top (invalid type _):
     ./in.cue:29:8
+    ./in.cue:29:12
 
 Result:
 (_|_){
@@ -78,6 +79,7 @@
     a: (_|_){
       // [eval] incompleteIndex.a: invalid index top (invalid type _):
       //     ./in.cue:29:8
+      //     ./in.cue:29:12
     }
   }
 }
diff --git a/cue/testdata/references/index.txtar b/cue/testdata/references/index.txtar
index 56d8e5f..2fbcbe6 100644
--- a/cue/testdata/references/index.txtar
+++ b/cue/testdata/references/index.txtar
@@ -43,14 +43,18 @@
     ./in.cue:17:20
 booleanIndex: invalid index true (invalid type bool):
     ./in.cue:18:15
+    ./in.cue:18:18
 indexOutOfBounds3: invalid list index 4 (out of bounds):
     ./in.cue:19:30
 negativeIndex: invalid index -1 (index must be non-negative):
     ./in.cue:20:16
+    ./in.cue:20:26
 varIndexTooLarge.a: index out of range [3] with length 3:
     ./in.cue:24:18
 varNegativeIndex.a: index n out of range [-1]:
     ./in.cue:29:8
+    ./in.cue:28:8
+    ./in.cue:29:18
 
 Result:
 (_|_){
@@ -87,6 +91,7 @@
   booleanIndex: (_|_){
     // [eval] booleanIndex: invalid index true (invalid type bool):
     //     ./in.cue:18:15
+    //     ./in.cue:18:18
   }
   indexOutOfBounds3: (_|_){
     // [eval] indexOutOfBounds3: invalid list index 4 (out of bounds):
@@ -95,6 +100,7 @@
   negativeIndex: (_|_){
     // [eval] negativeIndex: invalid index -1 (index must be non-negative):
     //     ./in.cue:20:16
+    //     ./in.cue:20:26
   }
   varIndexTooLarge: (_|_){
     // [eval]
@@ -110,6 +116,8 @@
     a: (_|_){
       // [eval] varNegativeIndex.a: index n out of range [-1]:
       //     ./in.cue:29:8
+      //     ./in.cue:28:8
+      //     ./in.cue:29:18
     }
   }
 }
diff --git a/cue/testdata/resolve/016_index.txtar b/cue/testdata/resolve/016_index.txtar
index 296f877..b18c5ee 100644
--- a/cue/testdata/resolve/016_index.txtar
+++ b/cue/testdata/resolve/016_index.txtar
@@ -103,16 +103,19 @@
     ./in.cue:7:5
 e3: invalid index true (invalid type bool):
     ./in.cue:8:5
+    ./in.cue:8:8
 e4: index out of range [3] with length 3:
     ./in.cue:9:15
 e5: invalid index -1 (index must be non-negative):
     ./in.cue:10:5
+    ./in.cue:10:15
 e6: invalid list index 1 (out of bounds):
     ./in.cue:11:16
 e7: index out of range [3] with length 3:
     ./in.cue:12:15
 e8: invalid index -1 (index must be non-negative):
     ./in.cue:13:5
+    ./in.cue:13:15
 e9: invalid list index 1 (out of bounds):
     ./in.cue:14:16
 
@@ -142,6 +145,7 @@
   e3: (_|_){
     // [eval] e3: invalid index true (invalid type bool):
     //     ./in.cue:8:5
+    //     ./in.cue:8:8
   }
   e4: (_|_){
     // [eval] e4: index out of range [3] with length 3:
@@ -150,6 +154,7 @@
   e5: (_|_){
     // [eval] e5: invalid index -1 (index must be non-negative):
     //     ./in.cue:10:5
+    //     ./in.cue:10:15
   }
   e6: (_|_){
     // [eval] e6: invalid list index 1 (out of bounds):
@@ -162,6 +167,7 @@
   e8: (_|_){
     // [eval] e8: invalid index -1 (index must be non-negative):
     //     ./in.cue:13:5
+    //     ./in.cue:13:15
   }
   e9: (_|_){
     // [eval] e9: invalid list index 1 (out of bounds):
diff --git a/cue/testdata/resolve/018_slice.txtar b/cue/testdata/resolve/018_slice.txtar
index 775ba8f..813199f 100644
--- a/cue/testdata/resolve/018_slice.txtar
+++ b/cue/testdata/resolve/018_slice.txtar
@@ -65,8 +65,10 @@
     ./in.cue:7:5
 e6: cannot use "" (type string) as type int in slice index:
     ./in.cue:8:5
+    ./in.cue:8:9
 e7: cannot use "9" (type string) as type int in slice index:
     ./in.cue:9:5
+    ./in.cue:9:10
 
 Result:
 (_|_){
@@ -98,9 +100,11 @@
   e6: (_|_){
     // [eval] e6: cannot use "" (type string) as type int in slice index:
     //     ./in.cue:8:5
+    //     ./in.cue:8:9
   }
   e7: (_|_){
     // [eval] e7: cannot use "9" (type string) as type int in slice index:
     //     ./in.cue:9:5
+    //     ./in.cue:9:10
   }
 }
diff --git a/cue/testdata/resolve/024_structs.txtar b/cue/testdata/resolve/024_structs.txtar
index 7d16014..39912a2 100644
--- a/cue/testdata/resolve/024_structs.txtar
+++ b/cue/testdata/resolve/024_structs.txtar
@@ -55,6 +55,7 @@
     d: (_|_){
       // [incomplete] t.d: non-concrete value number in operand to *:
       //     ./in.cue:3:19
+      //     ./in.cue:3:5
     }
   }
   ti: (struct){
@@ -62,6 +63,8 @@
     d: (_|_){
       // [incomplete] ti.d: non-concrete value int in operand to *:
       //     ./in.cue:3:19
+      //     ./in.cue:3:5
+      //     ./in.cue:4:10
     }
   }
 }
diff --git a/cue/testdata/resolve/039_reference_to_root.txtar b/cue/testdata/resolve/039_reference_to_root.txtar
index 7736c0f..8bceff1 100644
--- a/cue/testdata/resolve/039_reference_to_root.txtar
+++ b/cue/testdata/resolve/039_reference_to_root.txtar
@@ -87,6 +87,7 @@
     d: (_|_){
       // [incomplete] c.d: non-concrete value int in operand to +:
       //     ./in.cue:4:5
+      //     ./in.cue:1:5
     }
   }
   x: (struct){
@@ -94,6 +95,7 @@
     c: (_|_){
       // [incomplete] x.c: non-concrete value int in operand to +:
       //     ./in.cue:8:5
+      //     ./in.cue:7:2
     }
   }
   y: (struct){
@@ -105,6 +107,7 @@
     c: (_|_){
       // [incomplete] v.c: non-concrete value int in operand to +:
       //     ./in.cue:16:5
+      //     ./in.cue:15:2
     }
   }
   w: (struct){
@@ -112,6 +115,7 @@
     c: (_|_){
       // [incomplete] w.c: non-concrete value int in operand to +:
       //     ./in.cue:16:5
+      //     ./in.cue:15:2
     }
   }
   wp: (struct){
@@ -119,6 +123,7 @@
     c: (_|_){
       // [incomplete] wp.c: non-concrete value int in operand to +:
       //     ./in.cue:16:5
+      //     ./in.cue:15:2
     }
   }
 }
diff --git a/cue/testdata/scalars/embed.txtar b/cue/testdata/scalars/embed.txtar
index fe0424f..9774e1a 100644
--- a/cue/testdata/scalars/embed.txtar
+++ b/cue/testdata/scalars/embed.txtar
@@ -166,6 +166,7 @@
       out: (_|_){
         // [incomplete] outPattern.sum.out: non-concrete value int in operand to +:
         //     ./in.cue:44:14
+        //     ./in.cue:45:9
       }
       #a: (int){ int }
       #b: (int){ int }
@@ -180,6 +181,7 @@
     sum: (_|_){
       // [incomplete] arithmetic.sum: non-concrete value int in operand to +:
       //     ./in.cue:53:9
+      //     ./in.cue:54:9
       #a: (int){ int }
       #b: (int){ int }
     }
diff --git a/internal/core/adt/adt.go b/internal/core/adt/adt.go
index 7c670a4..e77df49 100644
--- a/internal/core/adt/adt.go
+++ b/internal/core/adt/adt.go
@@ -54,7 +54,7 @@
 	default:
 		// Unknown type.
 		v = ctx.NewErrf(
-			"could not evaluate expression %s of type %T", ctx.Str(c.Expr()), c)
+			"could not evaluate expression %s of type %T", c.Expr(), c)
 	}
 
 	return ToVertex(v)
diff --git a/internal/core/adt/binop.go b/internal/core/adt/binop.go
index 4c87a49..e1d22c1 100644
--- a/internal/core/adt/binop.go
+++ b/internal/core/adt/binop.go
@@ -31,13 +31,13 @@
 	if left.Concreteness() > Concrete {
 		return &Bottom{
 			Code: IncompleteError,
-			Err:  c.Newf(msg, c.Str(left), op),
+			Err:  c.Newf(msg, left, op),
 		}
 	}
 	if right.Concreteness() > Concrete {
 		return &Bottom{
 			Code: IncompleteError,
-			Err:  c.Newf(msg, c.Str(right), op),
+			Err:  c.Newf(msg, right, op),
 		}
 	}
 
@@ -290,7 +290,7 @@
 	}
 
 	return c.NewErrf("invalid operands %s and %s to '%s' (type %s and %s)",
-		c.Str(left), c.Str(right), op, left.Kind(), right.Kind())
+		left, right, op, left.Kind(), right.Kind())
 }
 
 func cmpTonode(c *OpContext, op Op, r int) Value {
diff --git a/internal/core/adt/context.go b/internal/core/adt/context.go
index 8163714..4c3b6d0 100644
--- a/internal/core/adt/context.go
+++ b/internal/core/adt/context.go
@@ -26,7 +26,6 @@
 
 	"cuelang.org/go/cue/ast"
 	"cuelang.org/go/cue/errors"
-	"cuelang.org/go/cue/format"
 	"cuelang.org/go/cue/token"
 )
 
@@ -274,8 +273,9 @@
 
 func (c *OpContext) concreteIsPossible(op Op, x Expr) bool {
 	if !AssertConcreteIsPossible(op, x) {
-		c.AddErrf("invalid operand %s ('%s' requires concrete value)",
-			c.Str(x), op)
+		// No need to take position of expression.
+		c.AddErr(c.NewPosf(token.NoPos,
+			"invalid operand %s ('%s' requires concrete value)", x, op))
 		return false
 	}
 	return true
@@ -306,18 +306,6 @@
 }
 
 func (c *OpContext) addErrf(code ErrorCode, pos token.Pos, msg string, args ...interface{}) {
-	for i, a := range args {
-		switch x := a.(type) {
-		case Node:
-			args[i] = c.Str(x)
-		case ast.Node:
-			b, _ := format.Node(x)
-			args[i] = string(b)
-		case Feature:
-			args[i] = x.SelectorString(c.Runtime)
-		}
-	}
-
 	err := c.NewPosf(pos, msg, args...)
 	c.addErr(code, err)
 }
@@ -453,17 +441,17 @@
 // msg is used to mention the context in which an error occurred, if any.
 func (c *OpContext) Concrete(env *Environment, x Expr, msg interface{}) (result Value, complete bool) {
 
-	v, complete := c.Evaluate(env, x)
+	w, complete := c.Evaluate(env, x)
 
-	v, ok := c.getDefault(v)
+	w, ok := c.getDefault(w)
 	if !ok {
-		return v, false
+		return w, false
 	}
-	v = Unwrap(v)
+	v := Unwrap(w)
 
 	if !IsConcrete(v) {
 		complete = false
-		b := c.NewErrf("non-concrete value %v in operand to %s", c.Str(v), msg)
+		b := c.NewErrf("non-concrete value %v in operand to %s", w, msg)
 		b.Code = IncompleteError
 		v = b
 	}
@@ -504,7 +492,7 @@
 
 	if d.NumDefaults != 1 {
 		c.addErrf(IncompleteError, c.pos(),
-			"unresolved disjunction %s (type %s)", c.Str(d), d.Kind())
+			"unresolved disjunction %s (type %s)", d, d.Kind())
 		return nil, false
 	}
 	return c.getDefault(d.Values[0])
@@ -752,7 +740,7 @@
 		}
 
 	case nil:
-		// c.addErrf(IncompleteError, pos, "incomplete value %s", c.Str(x))
+		// c.addErrf(IncompleteError, pos, "incomplete value %s", x)
 		// return nil
 
 	case *Bottom:
@@ -847,10 +835,9 @@
 		return
 	}
 	if !IsConcrete(v) && v.Kind()&k != 0 {
-		c.addErrf(IncompleteError, pos(v),
-			"incomplete %s value '%s'", k, c.Str(v))
+		c.addErrf(IncompleteError, pos(v), "incomplete %s value '%s'", k, v)
 	} else {
-		c.AddErrf("cannot use %s (type %s) as type %s", c.Str(v), v.Kind(), k)
+		c.AddErrf("cannot use %s (type %s) as type %s", v, v.Kind(), k)
 	}
 }
 
@@ -864,10 +851,9 @@
 	}
 	if !IsConcrete(v) && v.Kind()&k != 0 {
 		c.addErrf(IncompleteError, pos(v),
-			"incomplete %s value '%s' in as", k, c.Str(v), as)
+			"incomplete %s value '%s' in as", k, v, as)
 	} else {
-		c.AddErrf("cannot use %s (type %s) as type %s in %v",
-			c.Str(v), v.Kind(), k, as)
+		c.AddErrf("cannot use %s (type %s) as type %s in %v", v, v.Kind(), k, as)
 	}
 }
 
@@ -912,11 +898,10 @@
 		switch orig.(type) {
 		case *ForClause:
 			c.addErrf(IncompleteError, pos(x),
-				"cannot range over %s (incomplete)",
-				c.Str(x))
+				"cannot range over %s (incomplete)", x)
 		default:
 			c.addErrf(IncompleteError, pos(x),
-				"%s undefined (%s is incomplete)", c.Str(orig), c.Str(x))
+				"%s undefined (%s is incomplete)", orig, x)
 		}
 		return emptyNode
 
@@ -937,12 +922,10 @@
 			switch orig.(type) {
 			case *ForClause:
 				c.addErrf(IncompleteError, pos(x),
-					"cannot range over %s (incomplete type %s)",
-					c.Str(x), kind)
+					"cannot range over %s (incomplete type %s)", x, kind)
 			default:
 				c.addErrf(IncompleteError, pos(x),
-					"%s undefined as %s is incomplete (type %s)",
-					c.Str(orig), c.Str(x), kind)
+					"%s undefined as %s is incomplete (type %s)", orig, x, kind)
 			}
 			return emptyNode
 
@@ -1108,7 +1091,7 @@
 
 	default:
 		c.addErrf(IncompleteError, c.pos(),
-			"non-concrete value %s (type %s)", c.Str(v), v.Kind())
+			"non-concrete value %s (type %s)", v, v.Kind())
 	}
 	return ""
 }
diff --git a/internal/core/adt/errors.go b/internal/core/adt/errors.go
index 1b20606..c990092 100644
--- a/internal/core/adt/errors.go
+++ b/internal/core/adt/errors.go
@@ -34,6 +34,7 @@
 import (
 	"cuelang.org/go/cue/ast"
 	"cuelang.org/go/cue/errors"
+	cueformat "cuelang.org/go/cue/format"
 	"cuelang.org/go/cue/token"
 )
 
@@ -260,20 +261,38 @@
 	return c.NewPosf(c.pos(), format, args...)
 }
 
+func appendNodePositions(a []token.Pos, n Node) []token.Pos {
+	if p := pos(n); p != token.NoPos {
+		a = append(a, p)
+	} else if v, ok := n.(*Vertex); ok {
+		for _, c := range v.Conjuncts {
+			a = appendNodePositions(a, c.x)
+		}
+	}
+	return a
+}
+
 func (c *OpContext) NewPosf(p token.Pos, format string, args ...interface{}) *ValueError {
 	var a []token.Pos
 	if len(c.positions) > 0 {
 		a = make([]token.Pos, 0, len(c.positions))
 		for _, n := range c.positions {
-			if p := pos(n); p != token.NoPos {
+			a = appendNodePositions(a, n)
+		}
+	}
+	for i, arg := range args {
+		switch x := arg.(type) {
+		case Node:
+			a = appendNodePositions(a, x)
+			args[i] = c.Str(x)
+		case ast.Node:
+			b, _ := cueformat.Node(x)
+			if p := x.Pos(); p != token.NoPos {
 				a = append(a, p)
-			} else if v, ok := n.(*Vertex); ok {
-				for _, c := range v.Conjuncts {
-					if p := pos(c.x); p != token.NoPos {
-						a = append(a, p)
-					}
-				}
 			}
+			args[i] = string(b)
+		case Feature:
+			args[i] = x.SelectorString(c.Runtime)
 		}
 	}
 	return &ValueError{
diff --git a/internal/core/adt/eval.go b/internal/core/adt/eval.go
index d2086cb..fa00b20 100644
--- a/internal/core/adt/eval.go
+++ b/internal/core/adt/eval.go
@@ -974,12 +974,11 @@
 
 	var err *ValueError
 	if k1 == k2 {
-		err = ctx.NewPosf(token.NoPos,
-			"conflicting values %s and %s", ctx.Str(v1), ctx.Str(v2))
+		err = ctx.NewPosf(token.NoPos, "conflicting values %s and %s", v1, v2)
 	} else {
 		err = ctx.NewPosf(token.NoPos,
 			"conflicting values %s and %s (mismatched types %s and %s)",
-			ctx.Str(v1), ctx.Str(v2), k1, k2)
+			v1, v2, k1, k2)
 	}
 
 	err.AddPosition(v1)
@@ -1005,7 +1004,7 @@
 		} else {
 			n.addErr(ctx.Newf(
 				"conflicting value %s (mismatched types %s and %s)",
-				ctx.Str(v), n.kind, k))
+				v, n.kind, k))
 		}
 	}
 
diff --git a/internal/core/adt/expr.go b/internal/core/adt/expr.go
index 648b74d..2e44ce8 100644
--- a/internal/core/adt/expr.go
+++ b/internal/core/adt/expr.go
@@ -477,13 +477,12 @@
 			mask |= NullKind
 		}
 		if k&mask != 0 {
-			ctx.addErrf(IncompleteError, ctx.pos(),
-				"non-concrete value %s for bound %s", ctx.Str(x.Expr), x.Op)
+			ctx.addErrf(IncompleteError, token.NoPos, // TODO(errors): use ctx.pos()?
+				"non-concrete value %s for bound %s", x.Expr, x.Op)
 			return nil
 		}
 		err := ctx.NewPosf(pos(x.Expr),
-			"invalid value %s (type %s) for bound %s",
-			ctx.Str(v), k, x.Op)
+			"invalid value %s (type %s) for bound %s", v, k, x.Op)
 		return &Bottom{Err: err}
 	}
 
@@ -565,8 +564,8 @@
 	}
 	if v.Concreteness() > Concrete {
 		// TODO(errors): analyze dependencies of x.Expr to get positions.
-		ctx.addErrf(IncompleteError, ctx.pos(),
-			"non-concrete value %s for bound %s", ctx.Str(x.Expr), x.Op)
+		ctx.addErrf(IncompleteError, token.NoPos, // TODO(errors): use ctx.pos()?
+			"non-concrete value %s for bound %s", x.Expr, x.Op)
 		return nil
 	}
 	return &BoundValue{x.Src, x.Op, v}
@@ -616,8 +615,7 @@
 		}
 		// TODO(errors): use "invalid value %v (not an %s)" if x is a
 		// predeclared identifier such as `int`.
-		err := c.Newf("invalid value %v (out of bound %s)",
-			c.Str(y), c.Str(x))
+		err := c.Newf("invalid value %v (out of bound %s)", y, x)
 		err.AddPosition(y)
 		return &Bottom{Src: c.src, Err: err, Code: EvalError}
 
@@ -934,8 +932,7 @@
 
 	switch v := v.(type) {
 	case nil:
-		c.addErrf(IncompleteError, c.pos(),
-			"non-concrete slice subject %s", c.Str(x.X))
+		c.addErrf(IncompleteError, c.pos(), "non-concrete slice subject %s", x.X)
 		return nil
 	case *Vertex:
 		if !v.IsList() {
@@ -997,7 +994,7 @@
 	if isError(v) {
 		return v
 	}
-	return c.NewErrf("cannot slice %v (type %s)", c.Str(v), v.Kind())
+	return c.NewErrf("cannot slice %v (type %s)", v, v.Kind())
 }
 
 // An Interpolation is a string interpolation.
@@ -1097,10 +1094,10 @@
 	}
 	if k&expectedKind != BottomKind {
 		c.addErrf(IncompleteError, pos(x.X),
-			"operand %s of '%s' not concrete (was %s)", c.Str(x.X), op, k)
+			"operand %s of '%s' not concrete (was %s)", x.X, op, k)
 		return nil
 	}
-	return c.NewErrf("invalid operation %s (%s %s)", c.Str(x), op, k)
+	return c.NewErrf("invalid operation %s (%s %s)", x, op, k)
 }
 
 // BinaryExpr is a binary expression.
@@ -1244,8 +1241,7 @@
 		// value to be called with zero arguments.
 		switch {
 		case f.Src != nil:
-			c.addErrf(0, pos(x.Fun),
-				"cannot call previously called validator %s", c.Str(x.Fun))
+			c.AddErrf("cannot call previously called validator %s", x.Fun)
 
 		case f.Builtin.IsValidator(len(x.Args)):
 			v := *f
@@ -1257,8 +1253,7 @@
 		}
 
 	default:
-		c.addErrf(0, pos(x.Fun), "cannot call non-function %s (type %s)",
-			c.Str(x.Fun), kind(fun))
+		c.AddErrf("cannot call non-function %s (type %s)", x.Fun, kind(fun))
 		return nil
 	}
 	args := []Value{}
@@ -1269,7 +1264,7 @@
 			// There SHOULD be an error in the context. If not, we generate
 			// one.
 			c.Assertf(pos(x.Fun), c.HasErr(),
-				"argument %d to function %s is incomplete", i, c.Str(x.Fun))
+				"argument %d to function %s is incomplete", i, x.Fun)
 
 		case *Bottom:
 			// TODO(errors): consider adding an argument index for this errors.
@@ -1488,7 +1483,7 @@
 		buf.WriteString(")")
 	}
 
-	vErr := c.NewPosf(src, "invalid value %s (does not satisfy %s)", c.Str(args[0]), buf.String())
+	vErr := c.NewPosf(src, "invalid value %s (does not satisfy %s)", args[0], buf.String())
 	vErr.err = err
 
 	for _, v := range args {
diff --git a/internal/core/adt/feature.go b/internal/core/adt/feature.go
index 29585c5..2df3656 100644
--- a/internal/core/adt/feature.go
+++ b/internal/core/adt/feature.go
@@ -196,7 +196,7 @@
 			if src == nil {
 				src = v
 			}
-			c.AddErrf("invalid index %v: %v", c.Str(src), err)
+			c.AddErrf("invalid index %v: %v", src, err)
 			return InvalidLabel
 		}
 		if i < 0 {
@@ -204,11 +204,10 @@
 			case nil, *Num, *UnaryExpr:
 				// If the value is a constant, we know it is always an error.
 				// UnaryExpr is an approximation for a constant value here.
-				c.AddErrf("invalid index %s (index must be non-negative)",
-					c.Str(x))
+				c.AddErrf("invalid index %s (index must be non-negative)", x)
 			default:
 				// Use a different message is it is the result of evaluation.
-				c.AddErrf("index %s out of range [%s]", c.Str(src), c.Str(x))
+				c.AddErrf("index %s out of range [%s]", src, x)
 			}
 			return InvalidLabel
 		}
@@ -224,8 +223,7 @@
 
 	default:
 		if src != nil {
-			c.AddErrf("invalid index %s (invalid type %v)",
-				c.Str(src), v.Kind())
+			c.AddErrf("invalid index %s (invalid type %v)", src, v.Kind())
 		} else {
 			c.AddErrf("invalid index type %v", v.Kind())
 		}
diff --git a/internal/core/adt/simplify.go b/internal/core/adt/simplify.go
index 4bf0876..0d1d76b 100644
--- a/internal/core/adt/simplify.go
+++ b/internal/core/adt/simplify.go
@@ -154,7 +154,7 @@
 			fallthrough
 
 		case d.Negative:
-			return ctx.NewErrf("incompatible bounds %v and %v", ctx.Str(x), ctx.Str(y))
+			return ctx.NewErrf("incompatible bounds %v and %v", x, y)
 		}
 
 	case x.Op == NotEqualOp:
diff --git a/internal/core/compile/builtin.go b/internal/core/compile/builtin.go
index feb7ade..a36531f 100644
--- a/internal/core/compile/builtin.go
+++ b/internal/core/compile/builtin.go
@@ -69,7 +69,7 @@
 			if k&supportedByLen == adt.BottomKind {
 				return c.NewErrf("invalid argument type %v", k)
 			}
-			b := c.NewErrf("incomplete argument %s (type %v)", c.Str(v), k)
+			b := c.NewErrf("incomplete argument %s (type %v)", v, k)
 			b.Code = adt.IncompleteError
 			return b
 		}
diff --git a/internal/core/subsume/vertex.go b/internal/core/subsume/vertex.go
index 3d183f8..cb9d7c2 100644
--- a/internal/core/subsume/vertex.go
+++ b/internal/core/subsume/vertex.go
@@ -52,7 +52,7 @@
 
 	case *adt.ListMarker:
 		if !y.IsList() {
-			s.errf("list does not subsume %s (type %s)", ctx.Str(y), y.Kind())
+			s.errf("list does not subsume %s (type %s)", y, y.Kind())
 			return false
 		}
 		if !s.listVertices(x, y) {
@@ -157,8 +157,7 @@
 		s.gt = a
 		s.lt = y
 
-		s.errf("field %s not present in %s",
-			f.SelectorString(ctx), ctx.Str(y))
+		s.errf("field %s not present in %s", f, y)
 		return false
 	}
 
@@ -195,8 +194,7 @@
 			if s.Profile.IgnoreClosedness {
 				continue
 			}
-			s.errf("field %s not allowed in closed struct",
-				f.SelectorString(ctx))
+			s.errf("field %s not allowed in closed struct", f)
 			return false
 		}
 
diff --git a/internal/core/validate/validate.go b/internal/core/validate/validate.go
index 1af60c4..4b1fdbe 100644
--- a/internal/core/validate/validate.go
+++ b/internal/core/validate/validate.go
@@ -92,7 +92,7 @@
 			x := x.Value()
 			v.add(&adt.Bottom{
 				Code: adt.IncompleteError,
-				Err:  v.ctx.Newf("incomplete value %v", v.ctx.Str(x)),
+				Err:  v.ctx.Newf("incomplete value %v", x),
 			})
 		}
 	}
diff --git a/internal/core/validate/validate_test.go b/internal/core/validate/validate_test.go
index 9d395a2..1e56edb 100644
--- a/internal/core/validate/validate_test.go
+++ b/internal/core/validate/validate_test.go
@@ -100,7 +100,7 @@
 		y: 2 + x
 		x: string
 		`,
-		out: "incomplete\ny: non-concrete value string in operand to +:\n    test:2:6",
+		out: "incomplete\ny: non-concrete value string in operand to +:\n    test:2:6\n    test:3:3",
 	}, {
 		desc: "allowed incomplete cycle",
 		in: `
diff --git a/pkg/struct/testdata/gen.txtar b/pkg/struct/testdata/gen.txtar
index a73f573..0476429 100644
--- a/pkg/struct/testdata/gen.txtar
+++ b/pkg/struct/testdata/gen.txtar
@@ -15,6 +15,7 @@
     ./in.cue:3:27
 t4: invalid value {a:1} (does not satisfy struct.MaxFields(0)):
     ./in.cue:6:5
+    ./in.cue:6:1
     ./in.cue:6:22
 
 Result: