Merge pull request #329 from PLC-lang/issue-273-Validation_Invalid_Fu…

…nction_return_types

added validation for function return types (#273)

src/lib.rs

@@ -21,7 +21,7 @@ use std::fs;
 use std::ops::Range;
 use std::path::Path;
 
-use ast::{PouType, SourceRange};
+use ast::{DataTypeDeclaration, PouType, SourceRange};
 use codespan_reporting::diagnostic::{self, Label};
 use codespan_reporting::files::SimpleFiles;
 use codespan_reporting::term::termcolor::{ColorChoice, StandardStream};
@@ -82,6 +82,7 @@ pub enum ErrNo {
     // pou related
     pou__missing_return_type,
     pou__unexpected_return_type,
+    pou__unsupported_return_type,
     pou__empty_variable_block,
 
     //variable related
@@ -141,6 +142,17 @@ impl Diagnostic {
         }
     }
 
+    pub fn function_unsupported_return_type(data_type: &DataTypeDeclaration) -> Diagnostic {
+        Diagnostic::SyntaxError {
+            message: format!(
+                "Data Type {:?} not supported as a function return type!",
+                data_type
+            ),
+            range: data_type.get_location(),
+            err_no: ErrNo::pou__unsupported_return_type,
+        }
+    }
+
     pub fn function_return_missing(range: SourceRange) -> Diagnostic {
         Diagnostic::SyntaxError {
             message: "Function Return type missing".into(),

src/parser.rs

@@ -268,6 +268,17 @@ fn parse_return_type(lexer: &mut ParseSession, pou_type: &PouType) -> Option<Dat
                     SourceRange::new(start_return_type..lexer.last_range.end),
                 ));
             }
+
+            if let DataTypeDeclaration::DataTypeDefinition { data_type, .. } = &declaration {
+                if matches!(
+                    data_type,
+                    DataType::EnumType { .. } | DataType::StructType { .. }
+                ) {
+                    lexer.accept_diagnostic(Diagnostic::function_unsupported_return_type(
+                        &declaration,
+                    ))
+                }
+            }
             Some(declaration)
         } else {
             //missing return type

src/parser/tests/function_parser_tests.rs

@@ -163,3 +163,195 @@ fn varargs_parameters_can_be_parsed() {
     };
     assert_eq!(format!("{:#?}", expected), format!("{:#?}", x).as_str());
 }
+
+// Tests for function return types
+// supported return types
+#[test]
+fn function_array_return_supported() {
+    //GIVEN FUNCTION returning an ARRAY
+    let function = "FUNCTION foo : ARRAY[0..3] OF INT VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_subrange_return_supported() {
+    //GIVEN FUNCTION returning a SubRange
+    let function = "FUNCTION foo : INT(0..10) VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_pointer_return_supported() {
+    //GIVEN FUNCTION returning a POINTER
+    let function = "FUNCTION foo : REF_TO INT VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+// STRING types
+#[test]
+fn function_string_return_supported() {
+    //GIVEN FUNCTION returning a STRING
+    let function = "FUNCTION foo : STRING VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_string_len_return_supported() {
+    //GIVEN FUNCTION returning a STRING[10]
+    let function = "FUNCTION foo : STRING[10] VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_wstring_return_supported() {
+    //GIVEN FUNCTION returning a WSTRING
+    let function = "FUNCTION foo : WSTRING VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_wstring_len_return_supported() {
+    //GIVEN FUNCTION returning a WSTRING[10]
+    let function = "FUNCTION foo : WSTRING[10] VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+// SCALAR types
+#[test]
+fn function_int_return_supported() {
+    //GIVEN FUNCTION returning an INT
+    let function = "FUNCTION foo : INT VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_bool_return_supported() {
+    //GIVEN FUNCTION returning a BOOL
+    let function = "FUNCTION foo : BOOL VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_type_enum_return_supported() {
+    // GIVEN FUNCTION returning a type ENUM
+    let function = "TYPE MyEnum: (green, yellow, red); END_TYPE
+	FUNCTION foo : MyEnum VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+#[test]
+fn function_type_struct_return_supported() {
+    // GIVEN FUNCTION returning a type STRUCT
+    let function = "TYPE MyStruct: STRUCT x : INT; y : INT; END_STRUCT END_TYPE
+	FUNCTION foo : MyStruct VAR_INPUT END_VAR END_FUNCTION";
+    //WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    //THEN there shouldn't be any diagnostics -> valid return type
+    assert_eq!(diagnostics, vec![]);
+}
+
+// unsupported return types
+#[test]
+fn function_inline_enum_return_unsupported() {
+    // GIVEN FUNCTION returning an inline ENUM
+    let function = "FUNCTION foo : (green, yellow, red) VAR_INPUT END_VAR END_FUNCTION";
+    // WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    // THEN there should be one diagnostic -> unsupported return type
+    assert_eq!(
+        diagnostics,
+        vec![Diagnostic::function_unsupported_return_type(
+            &DataTypeDeclaration::DataTypeDefinition {
+                data_type: DataType::EnumType {
+                    name: None,
+                    elements: vec!["green".into(), "yellow".into(), "red".into()]
+                },
+                location: (15..35).into()
+            }
+        )]
+    );
+}
+
+#[test]
+fn function_inline_struct_return_unsupported() {
+    // GIVEN FUNCTION returning an inline STRUCT
+    let function =
+        "FUNCTION foo : STRUCT x : INT; y : INT; END_STRUCT VAR_INPUT END_VAR END_FUNCTION";
+    // WHEN parsing is done
+    let lexer = lex(function);
+    let (_parse_result, diagnostics) = parse(lexer);
+    // THEN there should be one diagnostic -> unsupported return type
+    assert_eq!(
+        true,
+        diagnostics.contains(&Diagnostic::function_unsupported_return_type(
+            &DataTypeDeclaration::DataTypeDefinition {
+                data_type: DataType::StructType {
+                    name: None,
+                    variables: vec![
+                        Variable {
+                            name: "x".into(),
+                            location: SourceRange::undefined(),
+                            data_type: DataTypeDeclaration::DataTypeReference {
+                                location: SourceRange::undefined(),
+                                referenced_type: "INT".into()
+                            },
+                            initializer: None
+                        },
+                        Variable {
+                            name: "y".into(),
+                            location: SourceRange::undefined(),
+                            data_type: DataTypeDeclaration::DataTypeReference {
+                                location: SourceRange::undefined(),
+                                referenced_type: "INT".into()
+                            },
+                            initializer: None
+                        }
+                    ],
+                },
+                location: (15..50).into()
+            }
+        ))
+    );
+}

src/validation.rs

@@ -112,7 +112,7 @@ impl Validator {
     }
 
     pub fn visit_pou(&mut self, pou: &Pou, context: &ValidationContext) {
-        self.pou_validator.validate_pou(pou);
+        self.pou_validator.validate_pou(pou, context);
 
         for block in &pou.variable_blocks {
             self.visit_variable_container(context, block);

src/validation/pou_validator.rs

@@ -1,4 +1,5 @@
-use crate::{ast::Pou, Diagnostic};
+use super::ValidationContext;
+use crate::{ast::Pou, Diagnostic, PouType};
 
 /// validates POUs
 pub struct PouValidator {
@@ -12,5 +13,18 @@ impl PouValidator {
         }
     }
 
-    pub fn validate_pou(&mut self, _pou: &Pou) {}
+    pub fn validate_pou(&mut self, pou: &Pou, context: &ValidationContext) {
+        if pou.pou_type == PouType::Function {
+            self.validate_function(pou, context);
+        };
+    }
+
+    pub fn validate_function(&mut self, pou: &Pou, context: &ValidationContext) {
+        let return_type = context.index.find_return_type(&pou.name);
+        // functions must have a return type
+        if return_type.is_none() {
+            self.diagnostics
+                .push(Diagnostic::function_return_missing(pou.location.to_owned()));
+        }
+    }
 }

src/validation/tests.rs

@@ -16,6 +16,8 @@ mod variable_validation_tests;
 
 mod statement_validation_tests;
 
+mod pou_validation_tests;
+
 pub fn parse_and_validate(src: &str) -> Vec<Diagnostic> {
     let mut idx = Index::new();
     let (mut ast, _) = parse(lex(src));

src/validation/tests/pou_validation_tests.rs

@@ -0,0 +1,14 @@
+use crate::{validation::tests::parse_and_validate, Diagnostic};
+
+// unsupported return types
+#[test]
+fn function_no_return_unsupported() {
+    // GIVEN FUNCTION with no return type
+    // WHEN parse_and_validate is done
+    let diagnostics = parse_and_validate("FUNCTION foo VAR_INPUT END_VAR END_FUNCTION");
+    // THEN there should be one diagnostic -> missing return type
+    assert_eq!(
+        diagnostics,
+        vec![Diagnostic::function_return_missing((0..43).into())]
+    );
+}