cleanup recent code change and clarified the name of test cases

ast/let_statement.go

@@ -18,7 +18,9 @@ func (ls *LetStatement) String() string {
 	var out bytes.Buffer
 
 	out.WriteString(ls.TokenLiteral() + " ")
-	out.WriteString(ls.Name.String())
+	if ls.Name != nil {
+		out.WriteString(ls.Name.String())
+	}
 	out.WriteString(" = ")
 
 	if ls.Value != nil {

parser/parser.go

@@ -156,13 +156,14 @@ func (p *parser) noPrefixParseFnError(t token.Type) {
 }
 
 func (p *parser) parseStatement() ast.Statement {
+	// Warning: ast.Statement is an interface so please make sure all callee
+	// methods do not return nil from themselves.
+	// If you are adding another case here, please make sure the callee does
+	// not return nil or you should add nil checking and explicitly return
+	// concrete nil. (https://github.com/gobuffalo/plush/pull/171)
 	switch p.curToken.Type {
 	case token.LET:
-		l := p.parseLetStatement()
-		if l == nil {
-			return nil
-		}
-		return l
+		return p.parseLetStatement()
 	case token.S_START:
 		p.nextToken()
 		return p.parseStatement()
@@ -196,7 +197,7 @@ func (p *parser) parseLetStatement() *ast.LetStatement {
 	stmt := &ast.LetStatement{TokenAble: ast.TokenAble{Token: p.curToken}}
 
 	if !p.expectPeek(token.IDENT) {
-		return nil
+		return stmt
 	}
 
 	stmt.Name = &ast.Identifier{TokenAble: ast.TokenAble{Token: p.curToken}, Value: p.curToken.Literal}

variables_test.go

@@ -28,18 +28,24 @@ func Test_Let_Reassignment(t *testing.T) {
 	r.Equal("bar\n    \n  \nbaz", strings.TrimSpace(s))
 }
 
-func Test_Let_Ident_NotInitialized(t *testing.T) {
+func Test_Let_SyntaxError_NoEqualSign(t *testing.T) {
 	r := require.New(t)
-	input := `<% let foo
-		if (foo){
-			foo = 1
-		}
-	%>`
+	input := `<% let foo %>`
 
 	ctx := NewContext()
 
 	_, err := Render(input, ctx)
-	r.Error(err)
+	r.ErrorContains(err, "expected next token to be =")
+}
+
+func Test_Let_SyntaxError_NoIdentifier(t *testing.T) {
+	r := require.New(t)
+	input := `<% let = %>`
+
+	ctx := NewContext()
+
+	_, err := Render(input, ctx)
+	r.ErrorContains(err, "expected next token to be IDENT")
 }
 
 func Test_Let_Reassignment_UnknownIdent(t *testing.T) {
@@ -50,7 +56,7 @@ func Test_Let_Reassignment_UnknownIdent(t *testing.T) {
 	ctx.Set("myArray", []string{"a", "b"})
 
 	_, err := Render(input, ctx)
-	r.Error(err)
+	r.ErrorContains(err, "\"foo\": unknown identifier")
 }
 
 func Test_Let_Inside_Helper(t *testing.T) {