extract and test

internal/decoder/decoder.go

@@ -7,6 +7,7 @@ import (
 	"context"
 
 	"github.com/hashicorp/hcl-lang/decoder"
+	"github.com/hashicorp/hcl-lang/lang"
 	"github.com/hashicorp/hcl-lang/reference"
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/terraform-ls/internal/codelens"
@@ -92,7 +93,9 @@ func DecoderContext(ctx context.Context) decoder.DecoderContext {
 		}
 	}
 
-	validations := validations.ValidationFuncs()
+	validations := []lang.ValidationFunc{
+		validations.UnReferencedOrigin,
+	}
 	dCtx.Validations = append(dCtx.Validations, validations...)
 
 	return dCtx

internal/decoder/validations/unreferenced_origin.go

@@ -0,0 +1,43 @@
+package validations
+
+import (
+	"context"
+
+	"github.com/hashicorp/hcl-lang/decoder"
+	"github.com/hashicorp/hcl-lang/lang"
+	"github.com/hashicorp/hcl-lang/reference"
+	"github.com/hashicorp/hcl/v2"
+)
+
+func UnReferencedOrigin(ctx context.Context) lang.DiagnosticsMap {
+	pathCtx, err := decoder.PathCtx(ctx)
+	if err != nil {
+		// TODO
+	}
+
+	diagsMap := make(lang.DiagnosticsMap)
+
+	for _, origin := range pathCtx.ReferenceOrigins {
+		matchableOrigin, ok := origin.(reference.MatchableOrigin)
+		if !ok {
+			// TODO: add a diag here
+			continue
+		}
+
+		_, ok = pathCtx.ReferenceTargets.Match(matchableOrigin)
+		if !ok {
+			// target not found
+			diagsMap[origin.OriginRange().Filename] = hcl.Diagnostics{
+				&hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "No reference found", // TODO: Is there more we can state here?
+					Subject:  origin.OriginRange().Ptr(),
+				},
+			}
+			continue
+		}
+
+	}
+
+	return diagsMap
+}

internal/decoder/validations/unreferenced_origin_test.go

@@ -0,0 +1,44 @@
+package validations
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"github.com/hashicorp/hcl-lang/lang"
+	"github.com/hashicorp/hcl/v2"
+)
+
+func TestUnReferencedOrigin(t *testing.T) {
+	ctx := context.Background()
+	// build pathdecoder
+	// set pathctx
+	// ctx = withPathContext(ctx, d.pathCtx)
+
+	tests := []struct {
+		name string
+		ctx  context.Context
+		want lang.DiagnosticsMap
+	}{
+		{
+			name: "unreferenced variable",
+			ctx:  ctx,
+			want: lang.DiagnosticsMap{
+				"test.tf": hcl.Diagnostics{
+					&hcl.Diagnostic{
+						Severity: hcl.DiagError,
+						Summary:  "No reference found",
+						Subject:  &hcl.Range{},
+					},
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := UnReferencedOrigin(tt.ctx); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("UnReferencedOrigin() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}