From 13ff341447ed1624e26edd13ec97ffb534f1bb1c Mon Sep 17 00:00:00 2001
From: Pam Selle <204372+pselle@users.noreply.github.com>
Date: Tue, 22 Oct 2019 15:16:43 -0400
Subject: [PATCH 1/2] Add a special error for each.value

---
 terraform/context_apply_test.go |  2 +-
 terraform/evaluate.go           | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/terraform/context_apply_test.go b/terraform/context_apply_test.go
index 203bd015d6..e4f9aafee6 100644
--- a/terraform/context_apply_test.go
+++ b/terraform/context_apply_test.go
@@ -2079,7 +2079,7 @@ func TestContext2Apply_provisionerDestroyForEach(t *testing.T) {
 	if diags == nil {
 		t.Fatal("should error")
 	}
-	if !strings.Contains(diags.Err().Error(), `Reference to "each" in context without for_each`) {
+	if !strings.Contains(diags.Err().Error(), "each.value is unknown and cannot be used in this context") {
 		t.Fatal("unexpected error:", diags.Err())
 	}
 }
diff --git a/terraform/evaluate.go b/terraform/evaluate.go
index 6681f8ddcb..a842f7bdc5 100644
--- a/terraform/evaluate.go
+++ b/terraform/evaluate.go
@@ -185,6 +185,16 @@ func (d *evaluationStateData) GetForEachAttr(addr addrs.ForEachAttr, rng tfdiags
 		returnVal = d.InstanceKeyData.EachKey
 	case "value":
 		returnVal = d.InstanceKeyData.EachValue
+
+		if returnVal == cty.NilVal {
+			diags = diags.Append(&hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  `each.value is unknown and cannot be used in this context`,
+				Detail:   fmt.Sprintf(`A reference to "each.value" has been used in a context in which it unavailable, such as after the config no longer contains the value in its "for_each" expression. Remove this reference to each.value in your config to work around this error.`),
+				Subject:  rng.ToHCL().Ptr(),
+			})
+			return cty.UnknownVal(cty.DynamicPseudoType), diags
+		}
 	default:
 		diags = diags.Append(&hcl.Diagnostic{
 			Severity: hcl.DiagError,

From 86d69bbe1868269677359c58679acb11686c2c74 Mon Sep 17 00:00:00 2001
From: Pam Selle <204372+pselle@users.noreply.github.com>
Date: Wed, 23 Oct 2019 11:18:10 -0400
Subject: [PATCH 2/2] Tweak the message mildly

---
 terraform/evaluate.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/terraform/evaluate.go b/terraform/evaluate.go
index a842f7bdc5..9e71d3efa8 100644
--- a/terraform/evaluate.go
+++ b/terraform/evaluate.go
@@ -189,8 +189,8 @@ func (d *evaluationStateData) GetForEachAttr(addr addrs.ForEachAttr, rng tfdiags
 		if returnVal == cty.NilVal {
 			diags = diags.Append(&hcl.Diagnostic{
 				Severity: hcl.DiagError,
-				Summary:  `each.value is unknown and cannot be used in this context`,
-				Detail:   fmt.Sprintf(`A reference to "each.value" has been used in a context in which it unavailable, such as after the config no longer contains the value in its "for_each" expression. Remove this reference to each.value in your config to work around this error.`),
+				Summary:  `each.value cannot be used in this context`,
+				Detail:   fmt.Sprintf(`A reference to "each.value" has been used in a context in which it unavailable, such as when the configuration no longer contains the value in its "for_each" expression. Remove this reference to each.value in your configuration to work around this error.`),
 				Subject:  rng.ToHCL().Ptr(),
 			})
 			return cty.UnknownVal(cty.DynamicPseudoType), diags