feat(validation): Struct initializers within arrays (PLC-lang#996)

Previously we accepted `arr := [foo := 0, bar := 1]` where `foo` and `bar` are struct fields. Doing so resulted in weird codegen issues documented in PLC-lang#965. This commit disallows this behavior and instead forces users to use parentheses when initializing structs within arrays, e.g. `arr := [(foo := 0, bar := 1), (...)]`.

compiler/plc_ast/src/ast.rs

@@ -553,7 +553,7 @@ fn replace_reference(
     Some(*old_data_type)
 }
 
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum ReferenceAccess {
     /**
      * a, a.b

compiler/plc_ast/src/literals.rs

@@ -38,14 +38,14 @@ pub enum AstLiteral {
     Array(Array),
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Date {
     year: i32,
     month: u32,
     day: u32,
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct DateAndTime {
     year: i32,
     month: u32,
@@ -56,15 +56,15 @@ pub struct DateAndTime {
     nano: u32,
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct TimeOfDay {
     hour: u32,
     min: u32,
     sec: u32,
     nano: u32,
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Time {
     pub day: f64,
     pub hour: f64,
@@ -76,13 +76,13 @@ pub struct Time {
     pub negative: bool,
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct StringValue {
     pub value: String,
     pub is_wide: bool,
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct Array {
     pub elements: Option<Box<AstNode>>, // expression-list
 }

compiler/plc_diagnostics/src/diagnostics.rs

@@ -664,6 +664,14 @@ impl Diagnostic {
         }
     }
 
+    pub fn array_struct_assignment(range: SourceLocation) -> Diagnostic {
+        Diagnostic::SyntaxError {
+            message: "Struct initializers within arrays have to be wrapped by `()`".to_string(),
+            range: vec![range],
+            err_no: ErrNo::arr__invalid_array_assignment,
+        }
+    }
+
     pub fn array_size(name: &str, len_lhs: usize, len_rhs: usize, range: SourceLocation) -> Diagnostic {
         Diagnostic::SemanticError {
             message: format!("Array {name} has a size of {len_lhs}, but {len_rhs} elements were provided"),

src/codegen/generators/expression_generator.rs

@@ -1774,6 +1774,7 @@ impl<'ink, 'b> ExpressionCodeGenerator<'ink, 'b> {
             AstStatement::MultipliedStatement { .. } => {
                 self.generate_literal_array(literal_statement).map(ExpressionValue::RValue)
             }
+            AstStatement::ParenExpression(expr) => self.generate_literal(expr),
             // if there is an expression-list this might be a struct-initialization or array-initialization
             AstStatement::ExpressionList { .. } => {
                 let type_hint = self.get_type_hint_info_for(literal_statement)?;