internal/shader: bug fix: check the type for composite literal

Closes #2348

internal/shader/expr.go

@@ -1048,6 +1048,10 @@ func (cs *compileState) parseExpr(block *block, fname string, expr ast.Expr, mar
 		if !ok {
 			return nil, nil, nil, false
 		}
+		if t.Main != shaderir.Array {
+			cs.addError(e.Pos(), fmt.Sprintf("invalid composite literal type %s", t.String()))
+			return nil, nil, nil, false
+		}
 		if t.Main == shaderir.Array && t.Length == -1 {
 			t.Length = len(e.Elts)
 		}

internal/shader/syntax_test.go

@@ -2724,7 +2724,7 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 	}
 }
 
-func TestTypeRedeclaration(t *testing.T) {
+func TestSyntaxTypeRedeclaration(t *testing.T) {
 	cases := []struct {
 		stmt string
 		err  bool
@@ -2752,7 +2752,7 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 	}
 }
 
-func TestSwizzling(t *testing.T) {
+func TestSyntaxSwizzling(t *testing.T) {
 	cases := []struct {
 		stmt string
 		err  bool
@@ -2841,7 +2841,7 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 	}
 }
 
-func TestConstType(t *testing.T) {
+func TestSyntaxConstType(t *testing.T) {
 	cases := []struct {
 		stmt string
 		err  bool
@@ -2970,7 +2970,7 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 }
 
 // Issue #2549
-func TestConstType2(t *testing.T) {
+func TestSyntaxConstType2(t *testing.T) {
 	cases := []struct {
 		stmt string
 		err  bool
@@ -2999,3 +2999,31 @@ func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
 		}
 	}
 }
+
+// Issue #2348
+func TestSyntaxCompositeLit(t *testing.T) {
+	cases := []struct {
+		stmt string
+		err  bool
+	}{
+		{stmt: "_ = undefined{1, 2, 3, 4}", err: true},
+		{stmt: "_ = int{1, 2, 3, 4}", err: true},
+		{stmt: "_ = vec4{1, 2, 3, 4}", err: true},
+	}
+
+	for _, c := range cases {
+		stmt := c.stmt
+		src := fmt.Sprintf(`package main
+
+func Fragment(position vec4, texCoord vec2, color vec4) vec4 {
+	%s
+	return position
+}`, stmt)
+		_, err := compileToIR([]byte(src))
+		if err == nil && c.err {
+			t.Errorf("%s must return an error but does not", stmt)
+		} else if err != nil && !c.err {
+			t.Errorf("%s must not return nil but returned %v", stmt, err)
+		}
+	}
+}