Keep in a pick only what reads of its name address, look frames up on the stack alone, and refuse a name read once whole

draws.go

@@ -7,9 +7,9 @@ import "strings"
 // so the same read written twice reads one value; and the frame of each name scope a read
 // entered past its owner.
 type drawMemo struct {
-	variant map[string]node
-	value   map[string]readValue
-	frames  map[*nameScope]*pickFrame
+	variant       map[string]node
+	value         map[string]readValue
+	enteredFrames map[*nameScope]*pickFrame
 }
 
 // groupDraws is what one render's draw group has drawn for its reference paths: a memo, and the
@@ -31,10 +31,10 @@ type renderTrace func(group string, row renderedRow, a arm)
 // renderDraws is one render's reference draws: the unnamed draw group's, and each named one's;
 // a test's trace of its reads; and the frames of the name scopes rendering.
 type renderDraws struct {
-	unnamed groupDraws
-	named   map[string]*groupDraws
-	trace   renderTrace
-	frames  *frameStack
+	unnamed    groupDraws
+	named      map[string]*groupDraws
+	trace      renderTrace
+	frameStack *frameStack
 }
 
 // renderScope is where a render reads its reference paths: its reference draws, in the draw group of the
@@ -45,11 +45,9 @@ type renderScope struct {
 	draws *renderDraws
 	group string
 	row   renderedRow
-	// entry is the memo of the read that entered the category rendering, nil where none did;
-	// base, the depth of the frame stack when it entered, below which no frame is the
-	// category's.
-	entry *drawMemo
-	base  int
+	// base is the depth of the frame stack when the read rendering the category entered it,
+	// below which no frame is the category's.
+	base int
 	// pick is the named pick what renders is part of, at pickKey, its path from the name; nil
 	// outside one.
 	pick    *namedPick