parser: Ensure the expression types

When assign a variable or returning a value it now ensures that the
expression matches the expected type.

To make this possible a %result_type% field was added to ast_node_t and
this field is used whenever to make the comparison.

Signed-off-by: Carlos Maniero <carlos@maniero.me>
Signed-off-by: Johnny Richard <johnny@johnnyrichard.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/test/parser_test.c b/test/parser_test.c
index 12b2cac..1371453 100644
--- a/test/parser_test.c
+++ b/test/parser_test.c
@@ -268,6 +268,21 @@ test_parse_basic_syntax_errors(const MunitParameter params[], void *user_data_or
   assert_parser_error("fn main(): beff { return 42; }", "type 'beff' is not defined");
   assert_parser_error("fn main(): i32 { return b; }", "identifier 'b' not defined");
   assert_parser_error("fn main(): i32 { b = 1; return b; }", "trying to assign 'b' before defining it.");
+  assert_parser_error("fn main(): i32 { let b: bool = 3; return 1; }",
+                      "incompatible types: expected 'bool', actual 'i32'.");
+  assert_parser_error("fn main(): i32 { let b: i32 = true; return 1; }",
+                      "incompatible types: expected 'i32', actual 'bool'.");
+  assert_parser_error("fn main(): i32 { let b: i32 = 1; b = true; return 1; }",
+                      "incompatible types: expected 'i32', actual 'bool'.");
+  assert_parser_error("fn main(): i32 { let b: bool = true; let c: i32 = b; return 1; }",
+                      "incompatible types: expected 'i32', actual 'bool'.");
+  assert_parser_error("fn main(): i32 { let b: i32 = 1; let c: bool = b; return 1; }",
+                      "incompatible types: expected 'bool', actual 'i32'.");
+  assert_parser_error("fn main(): i32 { let b: bool = 1; b = 42; return 1; }",
+                      "incompatible types: expected 'bool', actual 'i32'.");
+  assert_parser_error("fn main(): i32 { return true; }", "incompatible types: expected 'i32', actual 'bool'.");
+  assert_parser_error("fn main(): i32 { let a: bool = true; return a; }",
+                      "incompatible types: expected 'i32', actual 'bool'.");
   // FIXME: once function calls are implemented, this error should inform that
   // neither a variable or function call was found.
   assert_parser_error("fn main(): i32 { oxi 42; }", "unexpected token 'TOKEN_NAME' value='oxi'");