internal/core: reimplementation of closedness algorithm

Note: there are considerably more test lines, because
there is a) more position information, and b) there are
more tests. Insofar tests have been removed, it is because
the relevant code no longer exits.

So effectively, there are about 500 lines less code
related to closedness as a result of this change!

- Unify and UnifyAccept do all closedness checking wrt
  the parent locally. The AddVertex and UnifyAccept have
  been removed from eval.
- The old fieldSet is replaced with precomputed values in
  StructLit.
- Most optional and closedness logic has either been
  removed or moved from package eval to package adt.
- Instead of a separate Structs slice and closedness information
  there is now just a StructInfo slice with integrated CloseInfo.
- The Acceptor interface has been removed.
- A new algorithm computes closedness bottom up, instead
  of top-down. See closed.go in ADT for details.
- Recorded about a 15% reducing in running time, memory is
  of the same order.

Note that this removes many optimizations of the previous
implementation. Some of these (and others) could be added
later.

Fixes #599
Fixes #618

Change-Id: If6eec0b915b96067bcc4778bf63707827054b4d1
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/7985
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>

cmd/cue/cmd/testdata/script/eval_errs.txt

@@ -7,13 +7,17 @@ cmp stdout expect-stdout
 bar: empty disjunction: 2 related errors:
 bar.a: conflicting values "str" and int (mismatched types string and int):
     ./errs.cue:5:10
+    ./errs.cue:6:6
     ./errs.cue:6:16
 bar.b: conflicting values 2 and string (mismatched types int and string):
     ./errs.cue:5:21
+    ./errs.cue:6:6
     ./errs.cue:6:26
 x.q: conflicting values "goodbye" and "hello":
     ./errs.cue:1:4
     ./errs.cue:2:4
+    ./errs.cue:3:8
+    ./errs.cue:3:14
 -- errs.cue --
 a: "hello"
 b: "goodbye"

cue/testdata/builtins/closed.txtar

@@ -10,6 +10,7 @@ c: a & { a: c: int } // okay (non-recursive close)
 Errors:
 b: field `x` not allowed:
     ./in.cue:1:10
+    ./in.cue:5:4
     ./in.cue:5:10
 
 Result:
@@ -28,6 +29,7 @@ Result:
     x: (_|_){
       // [eval] b: field `x` not allowed:
       //     ./in.cue:1:10
+      //     ./in.cue:5:4
       //     ./in.cue:5:10
     }
   }

cue/testdata/builtins/issue490.txtar

@@ -11,6 +11,7 @@ B: A & {
 Errors:
 B: field `c` not allowed:
     ./test.cue:1:10
+    ./test.cue:6:4
     ./test.cue:7:2
 
 Result:
@@ -27,6 +28,7 @@ Result:
     c: (_|_){
       // [eval] B: field `c` not allowed:
       //     ./test.cue:1:10
+      //     ./test.cue:6:4
       //     ./test.cue:7:2
     }
   }

cue/testdata/cycle/structural.txtar

@@ -399,8 +399,10 @@ b13.root.a.0.0: structural cycle
 b14.root.b.1.1: structural cycle
 b4.x.y.0: structural cycle
 b6.b.a.0: conflicting values 1 and [1] (mismatched types int and list):
+    ./in.cue:63:8
     ./in.cue:63:16
     ./in.cue:63:17
+    ./in.cue:64:12
 b6.b.a.0.0: structural cycle
 b6.x.a.0: structural cycle
 b7.a.0: structural cycle
@@ -417,22 +419,26 @@ e3.a: conflicting values [a] and {c:a} (mismatched types list and struct):
     ./in.cue:290:8
 e3.a.0: conflicting values [a] and {c:a} (mismatched types list and struct):
     ./in.cue:289:8
+    ./in.cue:289:9
     ./in.cue:290:8
 e3.a.0: structural cycle
 e3.a.c: conflicting values [a] and {c:a} (mismatched types list and struct):
     ./in.cue:289:8
     ./in.cue:290:8
+    ./in.cue:290:11
 e3.a.c: structural cycle
 e3.b: conflicting values [b] and {c:b} (mismatched types list and struct):
     ./in.cue:292:8
     ./in.cue:293:8
 e3.b.0: conflicting values [b] and {c:b} (mismatched types list and struct):
     ./in.cue:292:8
+    ./in.cue:292:9
     ./in.cue:293:8
 e3.b.0: structural cycle
 e3.b.c: conflicting values [b] and {c:b} (mismatched types list and struct):
     ./in.cue:292:8
     ./in.cue:293:8
+    ./in.cue:293:11
 e3.b.c: structural cycle
 e4.a.0: conflicting values [{c:1}] and {} (mismatched types list and struct):
     ./in.cue:297:13
@@ -442,6 +448,7 @@ e4.a.0.0: conflicting values [{c:1}] and {c:1} (mismatched types list and struct
     ./in.cue:298:9
     ./in.cue:298:10
 e4.a.0.0: conflicting values [{c:1}] and {} (mismatched types list and struct):
+    ./in.cue:297:9
     ./in.cue:297:13
     ./in.cue:298:9
 e4.a.0.0: empty disjunction: 2 related errors:
@@ -454,6 +461,7 @@ e4.b.0.0: conflicting values [{c:1}] and {c:1} (mismatched types list and struct
     ./in.cue:300:10
 e4.b.0.0: conflicting values [{c:1}] and {} (mismatched types list and struct):
     ./in.cue:300:9
+    ./in.cue:301:9
     ./in.cue:301:13
 e4.b.0.0: empty disjunction: 2 related errors:
 p2.#T.a.b.link: structural cycle
@@ -594,8 +602,10 @@ Result:
         // [eval]
         0: (_|_){
           // [eval] b6.b.a.0: conflicting values 1 and [1] (mismatched types int and list):
+          //     ./in.cue:63:8
           //     ./in.cue:63:16
           //     ./in.cue:63:17
+          //     ./in.cue:64:12
           0: (_|_){
             // [structural cycle] b6.b.a.0.0: structural cycle
           }
@@ -1150,6 +1160,7 @@ Result:
         // [eval] e3.a.c: conflicting values [a] and {c:a} (mismatched types list and struct):
         //     ./in.cue:289:8
         //     ./in.cue:290:8
+        //     ./in.cue:290:11
         // e3.a.c: structural cycle
         c: (_|_){// 〈1;a〉
         }
@@ -1159,6 +1170,7 @@ Result:
       0: (_|_){
         // [eval] e3.a.0: conflicting values [a] and {c:a} (mismatched types list and struct):
         //     ./in.cue:289:8
+        //     ./in.cue:289:9
         //     ./in.cue:290:8
         // e3.a.0: structural cycle
         c: (_|_){// 〈1;a〉
@@ -1175,6 +1187,7 @@ Result:
         // [eval] e3.b.c: conflicting values [b] and {c:b} (mismatched types list and struct):
         //     ./in.cue:292:8
         //     ./in.cue:293:8
+        //     ./in.cue:293:11
         // e3.b.c: structural cycle
         c: (_|_){// 〈1;b〉
         }
@@ -1184,6 +1197,7 @@ Result:
       0: (_|_){
         // [eval] e3.b.0: conflicting values [b] and {c:b} (mismatched types list and struct):
         //     ./in.cue:292:8
+        //     ./in.cue:292:9
         //     ./in.cue:293:8
         // e3.b.0: structural cycle
         c: (_|_){// 〈1;b〉
@@ -1206,6 +1220,7 @@ Result:
         //     ./in.cue:298:9
         //     ./in.cue:298:10
         // e4.a.0.0: conflicting values [{c:1}] and {} (mismatched types list and struct):
+        //     ./in.cue:297:9
         //     ./in.cue:297:13
         //     ./in.cue:298:9
         // e4.a.0.0: empty disjunction: 2 related errors:
@@ -1226,6 +1241,7 @@ Result:
         //     ./in.cue:300:10
         // e4.b.0.0: conflicting values [{c:1}] and {} (mismatched types list and struct):
         //     ./in.cue:300:9
+        //     ./in.cue:301:9
         //     ./in.cue:301:13
         // e4.b.0.0: empty disjunction: 2 related errors:
         0: (struct){

cue/testdata/definitions/033_Issue_#153.txtar

@@ -66,6 +66,7 @@ listOfCloseds.0: field `b` not allowed:
     ./in.cue:2:21
     ./in.cue:5:10
     ./in.cue:13:1
+    ./in.cue:14:18
     ./in.cue:16:4
 
 Result:
@@ -81,6 +82,7 @@ Result:
         //     ./in.cue:2:21
         //     ./in.cue:5:10
         //     ./in.cue:13:1
+        //     ./in.cue:14:18
         //     ./in.cue:16:4
       }
     }

cue/testdata/definitions/037_closing_with_comprehensions.txtar

@@ -107,6 +107,7 @@ Errors:
 #E: field `f3` not allowed:
     ./in.cue:1:5
     ./in.cue:27:5
+    ./in.cue:27:10
     ./in.cue:29:3
 a: field `f3` not allowed:
     ./in.cue:1:5
@@ -137,6 +138,7 @@ Result:
       // [eval] #E: field `f3` not allowed:
       //     ./in.cue:1:5
       //     ./in.cue:27:5
+      //     ./in.cue:27:10
       //     ./in.cue:29:3
     }
   }

cue/testdata/definitions/embed.txtar

@@ -127,7 +127,7 @@ Result:
     a: (#struct){
       x: (int){ int }
       y: (int){ int }
-      b: (#struct){
+      b: (struct){
         c: (int){ int }
       }
     }

cue/testdata/definitions/hidden.txtar

@@ -12,41 +12,83 @@ import "example.com/pkg"
   _name: d: int
 }
 
-d: pkg.#D & { _name: d: int, _val: 4 }
+d: pkg.#D & { _name: d: int, _val: f: 4 }
 
 // TODO: this should fail, as the _name restricting it is in this
 // package.
-e: pkg.#D & #def & { _name: e: int, _val: int }
-f: e._val
+e: pkg.#D & #def & {
+  // This should fail as c is disallowed by the _name defined
+  // in this package
+  _name: c: int
+
+  // This should not fail, as this is a different _val
+  _val: g: int
+}
+
+f: pkg.#D & { _val: f: 4 }
+g: f._val
 
 -- pkg/bar.cue --
 package pkg
 
-#D: { _val: 3 }
+#D: { _val: f: 3 }
 
 -- out/eval --
-(struct){
+Errors:
+e._name: field `c` not allowed:
+    ./in.cue:6:10
+    ./in.cue:13:13
+    ./in.cue:16:10
+
+Result:
+(_|_){
+  // [eval]
   #def: (#struct){
     _name(:foo): (#struct){
       d: (int){ int }
     }
   }
   d: (#struct){
-    _val(example.com:pkg): (int){ 3 }
-    _name(:foo): (#struct){
+    _val(example.com:pkg): (#struct){
+      f: (int){ 3 }
+    }
+    _name(:foo): (struct){
       d: (int){ int }
     }
-    _val(:foo): (int){ 4 }
+    _val(:foo): (struct){
+      f: (int){ 4 }
+    }
   }
-  e: (#struct){
-    _val(example.com:pkg): (int){ 3 }
-    _name(:foo): (#struct){
+  e: (_|_){
+    // [eval]
+    _val(example.com:pkg): (#struct){
+      f: (int){ 3 }
+    }
+    _name(:foo): (_|_){
+      // [eval]
       d: (int){ int }
-      e: (int){ int }
+      c: (_|_){
+        // [eval] e._name: field `c` not allowed:
+        //     ./in.cue:6:10
+        //     ./in.cue:13:13
+        //     ./in.cue:16:10
+      }
     }
-    _val(:foo): (int){ int }
+    _val(:foo): (struct){
+      g: (int){ int }
+    }
+  }
+  f: (#struct){
+    _val(example.com:pkg): (#struct){
+      f: (int){ 3 }
+    }
+    _val(:foo): (struct){
+      f: (int){ 4 }
+    }
+  }
+  g: (struct){
+    f: (int){ 4 }
   }
-  f: (int){ int }
 }
 -- out/compile --
 --- in.cue
@@ -60,13 +102,22 @@ package pkg
     _name: {
       d: int
     }
-    _val: 4
+    _val: {
+      f: 4
+    }
   })
   e: ((〈import;"example.com/pkg"〉.#D & 〈0;#def〉) & {
     _name: {
-      e: int
+      c: int
+    }
+    _val: {
+      g: int
+    }
+  })
+  f: (〈import;"example.com/pkg"〉.#D & {
+    _val: {
+      f: 4
     }
-    _val: int
   })
-  f: 〈0;e〉._val
+  g: 〈0;f〉._val
 }

cue/testdata/definitions/list.txtar

@@ -11,7 +11,7 @@ c: #R & {
     w: (#list){
       0: (#struct){
       }
-      1: (#struct){
+      1: (struct){
         b: (int){ int }
       }
     }

cue/testdata/eval/conflicts.txtar

@@ -23,6 +23,7 @@ Errors:
 t0.v: conflicting values int and string (mismatched types int and string):
     ./in.cue:1:4
     ./in.cue:2:4
+    ./in.cue:5:12
 t1.x.a.b: conflicting values 4 and 3:
     ./in.cue:10:15
     ./in.cue:14:15
@@ -40,6 +41,7 @@ Result:
       // [eval] t0.v: conflicting values int and string (mismatched types int and string):
       //     ./in.cue:1:4
       //     ./in.cue:2:4
+      //     ./in.cue:5:12
     }
   }
   t1: (_|_){

cue/testdata/eval/disjunctions.txtar

@@ -64,9 +64,11 @@ Errors:
 f: empty disjunction: 2 related errors:
 f.name: conflicting values "int" and "str":
     ./in.cue:5:8
+    ./in.cue:15:4
     ./in.cue:15:16
 f.val: conflicting values 3 and string (mismatched types int and string):
     ./in.cue:9:7
+    ./in.cue:15:4
     ./in.cue:15:28
 
 Result:
@@ -97,14 +99,17 @@ Result:
     // [eval] f: empty disjunction: 2 related errors:
     // f.name: conflicting values "int" and "str":
     //     ./in.cue:5:8
+    //     ./in.cue:15:4
     //     ./in.cue:15:16
     // f.val: conflicting values 3 and string (mismatched types int and string):
     //     ./in.cue:9:7
+    //     ./in.cue:15:4
     //     ./in.cue:15:28
     name: (string){ "str" }
     val: (_|_){
       // [eval] f.val: conflicting values 3 and string (mismatched types int and string):
       //     ./in.cue:9:7
+      //     ./in.cue:15:4
       //     ./in.cue:15:28
     }
   }