diff --git a/terraform/eval_diff.go b/terraform/eval_diff.go
index 3ce4adbee..b675253e7 100644
--- a/terraform/eval_diff.go
+++ b/terraform/eval_diff.go
@@ -1,7 +1,6 @@
 package terraform
 
 import (
-	"bytes"
 	"fmt"
 	"log"
 	"strings"
@@ -567,49 +566,6 @@ func processIgnoreChangesIndividual(prior, proposed cty.Value, ignoreChanges []h
 	return ret, diags
 }
 
-// legacyFlagmapKeyForTraversal constructs a key string compatible with what
-// the flatmap package would generate for an attribute addressable by the given
-// traversal.
-//
-// This is used only to shim references to attributes within the diff and
-// state structures, which have not (at the time of writing) yet been updated
-// to use the newer HCL-based representations.
-func legacyFlatmapKeyForTraversal(traversal hcl.Traversal) string {
-	var buf bytes.Buffer
-	first := true
-	for _, step := range traversal {
-		if !first {
-			buf.WriteByte('.')
-		}
-		switch ts := step.(type) {
-		case hcl.TraverseRoot:
-			buf.WriteString(ts.Name)
-		case hcl.TraverseAttr:
-			buf.WriteString(ts.Name)
-		case hcl.TraverseIndex:
-			val := ts.Key
-			switch val.Type() {
-			case cty.Number:
-				bf := val.AsBigFloat()
-				buf.WriteString(bf.String())
-			case cty.String:
-				s := val.AsString()
-				buf.WriteString(s)
-			default:
-				// should never happen, since no other types appear in
-				// traversals in practice.
-				buf.WriteByte('?')
-			}
-		default:
-			// should never happen, since we've covered all of the types
-			// that show up in parsed traversals in practice.
-			buf.WriteByte('?')
-		}
-		first = false
-	}
-	return buf.String()
-}
-
 // a group of key-*ResourceAttrDiff pairs from the same flatmapped container
 type flatAttrDiff map[string]*ResourceAttrDiff
 
@@ -630,33 +586,6 @@ func (f flatAttrDiff) keepDiff(ignoreChanges map[string]bool) bool {
 	return false
 }
 
-// sets, lists and maps need to be compared for diff inclusion as a whole, so
-// group the flatmapped keys together for easier comparison.
-func groupContainers(d *InstanceDiff) map[string]flatAttrDiff {
-	isIndex := multiVal.MatchString
-	containers := map[string]flatAttrDiff{}
-	attrs := d.CopyAttributes()
-	// we need to loop once to find the index key
-	for k := range attrs {
-		if isIndex(k) {
-			// add the key, always including the final dot to fully qualify it
-			containers[k[:len(k)-1]] = flatAttrDiff{}
-		}
-	}
-
-	// loop again to find all the sub keys
-	for prefix, values := range containers {
-		for k, attrDiff := range attrs {
-			// we include the index value as well, since it could be part of the diff
-			if strings.HasPrefix(k, prefix) {
-				values[k] = attrDiff
-			}
-		}
-	}
-
-	return containers
-}
-
 // EvalDiffDestroy is an EvalNode implementation that returns a plain
 // destroy diff.
 type EvalDiffDestroy struct {