always report condition errors

The status in the face of errors didn't matter before, because we never
wrote out a plan with errors.

internal/terraform/context_plan2_test.go

@@ -3379,10 +3379,15 @@ func TestContext2Plan_preconditionErrors(t *testing.T) {
 			`, tc.condition)
 			m := testModuleInline(t, map[string]string{"main.tf": main})
 
-			_, diags := ctx.Plan(m, states.NewState(), DefaultPlanOpts)
+			plan, diags := ctx.Plan(m, states.NewState(), DefaultPlanOpts)
 			if !diags.HasErrors() {
 				t.Fatal("succeeded; want errors")
 			}
+
+			if !plan.Errored {
+				t.Fatal("plan failed to record error")
+			}
+
 			diag := diags[0]
 			if got, want := diag.Description().Summary, tc.wantSummary; got != want {
 				t.Errorf("unexpected summary\n got: %s\nwant: %s", got, want)
@@ -3390,6 +3395,13 @@ func TestContext2Plan_preconditionErrors(t *testing.T) {
 			if got, want := diag.Description().Detail, tc.wantDetail; !strings.Contains(got, want) {
 				t.Errorf("unexpected summary\ngot: %s\nwant to contain %q", got, want)
 			}
+
+			for _, kv := range plan.Checks.ConfigResults.Elements() {
+				// All these are configuration or evaluation errors
+				if kv.Value.Status != checks.StatusError {
+					t.Errorf("incorrect status, got %s", kv.Value.Status)
+				}
+			}
 		})
 	}
 }

internal/terraform/eval_conditions.go

@@ -103,6 +103,7 @@ func evalCheckRule(typ addrs.CheckType, rule *configs.CheckRule, ctx EvalContext
 
 	if diags.HasErrors() {
 		log.Printf("[TRACE] evalCheckRule: %s: %s", typ, diags.Err().Error())
+		return checkResult{Status: checks.StatusError}, diags
 	}
 
 	if !resultVal.IsKnown() {