diff --git a/cmd/eg/eg.go b/cmd/eg/eg.go
index 01dd5a9182..8d2342ab1b 100644
--- a/cmd/eg/eg.go
+++ b/cmd/eg/eg.go
@@ -1,4 +1,6 @@
 // The eg command performs example-based refactoring.
+// For documentation, run the command, or see Help in
+// code.google.com/p/go.tools/refactor/eg.
 package main
 
 import (
diff --git a/container/intsets/sparse.go b/container/intsets/sparse.go
index 4866aaa9ce..0ba7cb2346 100644
--- a/container/intsets/sparse.go
+++ b/container/intsets/sparse.go
@@ -15,6 +15,7 @@ package intsets
 
 // TODO(adonovan):
 // - Add SymmetricDifference(x, y *Sparse), i.e. x ∆ y.
+// - Add SubsetOf (x∖y=∅) and Intersects (x∩y≠∅) predicates.
 // - Add InsertAll(...int), RemoveAll(...int)
 // - Add 'bool changed' results for {Intersection,Difference}With too.
 //
@@ -25,6 +26,9 @@ package intsets
 // TODO(adonovan): experiment with making the root block indirect (nil
 // iff IsEmpty).  This would reduce the memory usage when empty and
 // might simplify the aliasing invariants.
+//
+// TODO(adonovan): opt: make UnionWith and Difference faster.
+// These are the hot-spots for go/pointer.
 
 import (
 	"bytes"
@@ -641,7 +645,7 @@ func (s *Sparse) Difference(x, y *Sparse) {
 			if sum != 0 {
 				sb = sb.next
 			} else {
-				// sb will be overrwritten or removed
+				// sb will be overwritten or removed
 			}
 
 			yb = yb.next
@@ -707,7 +711,7 @@ func (s *Sparse) String() string {
 //
 // Examples:
 //              {}.BitString() =      "0"
-//	     {4,5}.BitString() = "110000"
+//           {4,5}.BitString() = "110000"
 //            {-3}.BitString() =      "0.001"
 //      {-3,0,4,5}.BitString() = "110001.001"
 //
diff --git a/container/intsets/sparse_test.go b/container/intsets/sparse_test.go
index a00cbb3290..2338201903 100644
--- a/container/intsets/sparse_test.go
+++ b/container/intsets/sparse_test.go
@@ -458,6 +458,7 @@ func TestFailFastOnShallowCopy(t *testing.T) {
 // -- Benchmarks -------------------------------------------------------
 
 // TODO(adonovan):
+// - Add benchmarks of each method.
 // - Gather set distributions from pointer analysis.
 // - Measure memory usage.
 
diff --git a/go/loader/loader.go b/go/loader/loader.go
index 566108fa5e..82165a9f9e 100644
--- a/go/loader/loader.go
+++ b/go/loader/loader.go
@@ -297,6 +297,7 @@ func (conf *Config) fset() *token.FileSet {
 // the Config's FileSet, which is initialized if nil.
 //
 func (conf *Config) ParseFile(filename string, src interface{}) (*ast.File, error) {
+	// TODO(adonovan): use conf.build() etc like parseFiles does.
 	return parser.ParseFile(conf.fset(), filename, src, conf.ParserMode)
 }
 
diff --git a/oracle/describe.go b/oracle/describe.go
index 0f2ea4b9ac..01b245c44c 100644
--- a/oracle/describe.go
+++ b/oracle/describe.go
@@ -465,6 +465,9 @@ func (r *describeTypeResult) display(printf printfFunc) {
 		if len(r.methods) > 0 {
 			printf(r.node, "Method set:")
 			for _, meth := range r.methods {
+				// TODO(adonovan): print these relative
+				// to the owning package, not the
+				// query package.
 				printf(meth.Obj(), "\t%s", r.qpos.SelectionString(meth))
 			}
 		} else {
diff --git a/oracle/serial/serial.go b/oracle/serial/serial.go
index 631d9bc554..677687228e 100644
--- a/oracle/serial/serial.go
+++ b/oracle/serial/serial.go
@@ -124,8 +124,8 @@ type ImplementsType struct {
 // a "what" query.
 type SyntaxNode struct {
 	Description string `json:"desc"`  // description of syntax tree
-	Start       int    `json:"start"` // start offset (0-based)
-	End         int    `json:"end"`   // end offset
+	Start       int    `json:"start"` // start byte offset, 0-based
+	End         int    `json:"end"`   // end byte offset
 }
 
 // A What is the result of the "what" query, which quickly identifies