diff --git a/terraform/context_plan_test.go b/terraform/context_plan_test.go
index b488d5776b..1a4efde4f4 100644
--- a/terraform/context_plan_test.go
+++ b/terraform/context_plan_test.go
@@ -1887,6 +1887,66 @@ func TestContext2Plan_computedDataResource(t *testing.T) {
 	)
 }
 
+func TestContext2Plan_computedInFunction(t *testing.T) {
+	m := testModule(t, "plan-computed-in-function")
+	p := testProvider("aws")
+	p.GetSchemaReturn = &ProviderSchema{
+		ResourceTypes: map[string]*configschema.Block{
+			"aws_instance": {
+				Attributes: map[string]*configschema.Attribute{
+					"attr": {Type: cty.Number, Optional: true},
+				},
+			},
+		},
+		DataSources: map[string]*configschema.Block{
+			"aws_data_source": {
+				Attributes: map[string]*configschema.Attribute{
+					"computed": {Type: cty.List(cty.String), Computed: true},
+				},
+			},
+		},
+	}
+	p.DiffFn = testDiffFn
+
+	ctx := testContext2(t, &ContextOpts{
+		Config: m,
+		ProviderResolver: providers.ResolverFixed(
+			map[string]providers.Factory{
+				"aws": testProviderFuncFixed(p),
+			},
+		),
+	})
+
+	defer ctx.acquireRun("validate")()
+
+	pgb := &PlanGraphBuilder{
+		Config:     ctx.config,
+		State:      ctx.state,
+		Components: ctx.components,
+		Schemas:    ctx.schemas,
+		Targets:    ctx.targets,
+	}
+	graph, _ := pgb.Build(addrs.RootModuleInstance)
+
+	// walk
+	walker := &ContextGraphWalker{
+		Context:            ctx,
+		State:              ctx.state.SyncWrapper(),
+		Changes:            ctx.changes.SyncWrapper(),
+		Operation:          walkPlan,
+		StopContext:        ctx.runContext,
+		RootVariableValues: ctx.variables,
+	}
+	watchStop, watchWait := ctx.watchStop(walker)
+	diags := graph.Walk(walker)
+	close(watchStop)
+	<-watchWait
+
+	if diags.HasErrors() {
+		t.Fatalf("unexpected errors: %s", diags.Err())
+	}
+}
+
 func TestContext2Plan_computedDataCountResource(t *testing.T) {
 	m := testModule(t, "plan-computed-data-count")
 	p := testProvider("aws")
diff --git a/terraform/context_validate_test.go b/terraform/context_validate_test.go
index bac7bfa5b1..ddf3a679d3 100644
--- a/terraform/context_validate_test.go
+++ b/terraform/context_validate_test.go
@@ -174,6 +174,42 @@ func TestContext2Validate_computedVar(t *testing.T) {
 	}
 }
 
+func TestContext2Validate_computedInFunction(t *testing.T) {
+	p := testProvider("aws")
+	p.GetSchemaReturn = &ProviderSchema{
+		ResourceTypes: map[string]*configschema.Block{
+			"aws_instance": {
+				Attributes: map[string]*configschema.Attribute{
+					"attr": {Type: cty.Number, Optional: true},
+				},
+			},
+		},
+		DataSources: map[string]*configschema.Block{
+			"aws_data_source": {
+				Attributes: map[string]*configschema.Attribute{
+					"optional_attr": {Type: cty.String, Optional: true},
+					"computed":      {Type: cty.String, Computed: true},
+				},
+			},
+		},
+	}
+
+	m := testModule(t, "validate-computed-in-function")
+	c := testContext2(t, &ContextOpts{
+		Config: m,
+		ProviderResolver: providers.ResolverFixed(
+			map[string]providers.Factory{
+				"aws": testProviderFuncFixed(p),
+			},
+		),
+	})
+
+	diags := c.Validate()
+	if diags.HasErrors() {
+		t.Fatalf("unexpected error: %s", diags.Err())
+	}
+}
+
 // Test that validate allows through computed counts. We do this and allow
 // them to fail during "plan" since we can't know if the computed values
 // can be realized during a plan.
diff --git a/terraform/test-fixtures/plan-computed-in-function/main.tf b/terraform/test-fixtures/plan-computed-in-function/main.tf
new file mode 100644
index 0000000000..554394de6a
--- /dev/null
+++ b/terraform/test-fixtures/plan-computed-in-function/main.tf
@@ -0,0 +1,7 @@
+data "aws_data_source" "foo" {
+
+}
+
+resource "aws_instance" "bar" {
+    attr = "${length(data.aws_data_source.foo.computed)}"
+}
diff --git a/terraform/test-fixtures/validate-computed-in-function/main.tf b/terraform/test-fixtures/validate-computed-in-function/main.tf
new file mode 100644
index 0000000000..504e194261
--- /dev/null
+++ b/terraform/test-fixtures/validate-computed-in-function/main.tf
@@ -0,0 +1,7 @@
+data "aws_data_source" "foo" {
+    optional_attr = "value"
+}
+
+resource "aws_instance" "bar" {
+    attr = "${length(data.aws_data_source.foo.computed)}"
+}