diff --git a/pkg/eval/builtin_special.go b/pkg/eval/builtin_special.go
index a6e7f0d3..8b8bdb21 100644
--- a/pkg/eval/builtin_special.go
+++ b/pkg/eval/builtin_special.go
@@ -305,9 +305,10 @@ func evalModule(fm *Frame, key string, src *Source) (Ns, error) {
 
 	newFm := &Frame{
 		fm.Evaler, src,
+		diag.Ranging{From: 0, To: len(src.Code)},
 		modGlobal, make(Ns),
 		fm.ports,
-		0, len(src.Code), fm.addTraceback(), false,
+		fm.addTraceback(), false,
 	}
 
 	op, err := compile(newFm.Builtin.static(), modGlobal.static(), n, src)
diff --git a/pkg/eval/compile_effect.go b/pkg/eval/compile_effect.go
index 02457b6f..eb43475b 100644
--- a/pkg/eval/compile_effect.go
+++ b/pkg/eval/compile_effect.go
@@ -232,7 +232,7 @@ func (cp *compiler) formOp(n *parse.Form) effectOp {
 	redirOps := cp.redirOps(n.Redirs)
 	// TODO: n.ErrorRedir
 
-	return makeEffectOp(n, &formOp{saveVarsOps, assignmentOps, redirOps, specialOpFunc, headOp, argOps, optsOp, spaceyAssignOp, n.Range().From, n.Range().To})
+	return makeEffectOp(n, &formOp{saveVarsOps, assignmentOps, redirOps, specialOpFunc, headOp, argOps, optsOp, spaceyAssignOp})
 }
 
 func (cp *compiler) formOps(ns []*parse.Form) []effectOp {
@@ -252,10 +252,12 @@ type formOp struct {
 	argOps         []valuesOp
 	optsOp         valuesOpBody
 	spaceyAssignOp effectOp
-	begin, end     int
 }
 
 func (op *formOp) invoke(fm *Frame) (errRet error) {
+	// Save the range for the entire form.
+	formRange := fm.srcRange
+
 	// ec here is always a subevaler created in compiler.pipeline, so it can
 	// be safely modified.
 
@@ -357,8 +359,7 @@ func (op *formOp) invoke(fm *Frame) (errRet error) {
 		}
 	}
 
-	fm.begin, fm.end = op.begin, op.end
-
+	fm.srcRange = formRange
 	if headFn != nil {
 		return headFn.Call(fm, args, convertedOpts)
 	}
diff --git a/pkg/eval/frame.go b/pkg/eval/frame.go
index 6523bf60..c806728d 100644
--- a/pkg/eval/frame.go
+++ b/pkg/eval/frame.go
@@ -16,13 +16,13 @@ import (
 // shortly after creation; new Frame's are "forked" when needed.
 type Frame struct {
 	*Evaler
-	srcMeta *Source
+	srcMeta  *Source
+	srcRange diag.Ranging
 
 	local, up Ns
 	ports     []*Port
 
-	begin, end int
-	traceback  *stackTrace
+	traceback *stackTrace
 
 	background bool
 }
@@ -33,9 +33,10 @@ type Frame struct {
 func NewTopFrame(ev *Evaler, src *Source, ports []*Port) *Frame {
 	return &Frame{
 		ev, src,
+		diag.Ranging{From: 0, To: len(src.Code)},
 		ev.Global, make(Ns),
 		ports,
-		0, len(src.Code), nil, false,
+		nil, false,
 	}
 }
 
@@ -125,10 +126,10 @@ func (fm *Frame) fork(name string) *Frame {
 		}
 	}
 	return &Frame{
-		fm.Evaler, fm.srcMeta,
+		fm.Evaler, fm.srcMeta, fm.srcRange,
 		fm.local, fm.up,
 		newPorts,
-		fm.begin, fm.end, fm.traceback, fm.background,
+		fm.traceback, fm.background,
 	}
 }
 
@@ -201,7 +202,7 @@ func (fm *Frame) makeException(e error) error {
 func (fm *Frame) addTraceback() *stackTrace {
 	return &stackTrace{
 		entry: diag.NewContext(
-			fm.srcMeta.Name, fm.srcMeta.Code, fm.begin, fm.end),
+			fm.srcMeta.Name, fm.srcMeta.Code, fm.srcRange.From, fm.srcRange.To),
 		next: fm.traceback,
 	}
 }
@@ -209,6 +210,6 @@ func (fm *Frame) addTraceback() *stackTrace {
 // Amends the being and end of the current frame and returns the result of
 // fmt.Errorf.
 func (fm *Frame) errorpf(begin, end int, format string, args ...interface{}) error {
-	fm.begin, fm.end = begin, end
+	fm.srcRange = diag.Ranging{From: begin, To: end}
 	return fmt.Errorf(format, args...)
 }
diff --git a/pkg/eval/op.go b/pkg/eval/op.go
index 52cbee22..b98ad9de 100644
--- a/pkg/eval/op.go
+++ b/pkg/eval/op.go
@@ -29,7 +29,7 @@ type effectOpBody interface {
 
 // Executes an effectOp for side effects.
 func (op effectOp) exec(fm *Frame) error {
-	fm.begin, fm.end = op.From, op.To
+	fm.srcRange = op.Ranging
 	return op.body.invoke(fm)
 }
 
@@ -50,7 +50,7 @@ type valuesOpBody interface {
 
 // Executes a ValuesOp and produces values.
 func (op valuesOp) exec(fm *Frame) ([]interface{}, error) {
-	fm.begin, fm.end = op.From, op.To
+	fm.srcRange = op.Ranging
 	return op.body.invoke(fm)
 }
 
@@ -71,6 +71,6 @@ func (op lvaluesOp) exec(fm *Frame) ([]vars.Var, error) {
 	if op.body == nil {
 		return []vars.Var{}, nil
 	}
-	fm.begin, fm.end = op.From, op.To
+	fm.srcRange = op.Ranging
 	return op.body.invoke(fm)
 }