Fix unit expression

compiler/ast/src/passes/consumer.rs

@@ -61,9 +61,7 @@ pub trait ExpressionConsumer {
 
     fn consume_unary(&mut self, _input: UnaryExpression) -> Self::Output;
 
-    fn consume_unit(&mut self, _input: UnitExpression) -> Self::Output {
+    fn consume_unit(&mut self, _input: UnitExpression) -> Self::Output;
-        unreachable!("`UnitExpression`s should not be in the AST at this phase of compilation.")
-    }
 }
 
 /// A Consumer trait for statements in the AST.

compiler/parser/src/parser/statement.rs

@@ -117,12 +117,10 @@ impl ParserContext<'_> {
     fn parse_return_statement(&mut self) -> Result<ReturnStatement> {
         let start = self.expect(&Token::Return)?;
         let expression = match self.token.token {
-            Token::Semicolon => {
+            Token::Semicolon => Expression::Unit(UnitExpression { span: self.token.span }),
-                let span = self.expect(&Token::Semicolon)?;
-                Expression::Unit(UnitExpression { span })
-            }
             _ => self.parse_expression()?,
         };
+        self.expect(&Token::Semicolon)?;
         let span = start + expression.span();
         Ok(ReturnStatement { span, expression })
     }

compiler/passes/src/code_generation/visit_statements.rs

@@ -44,7 +44,7 @@ impl<'a> CodeGenerator<'a> {
     fn visit_return(&mut self, input: &'a ReturnStatement) -> String {
         match input.expression {
             // Skip empty return statements.
-            Expression::Tuple(ref tuple) if tuple.elements.is_empty() => String::new(),
+            Expression::Unit(_) => String::new(),
             _ => {
                 let (operand, mut expression_instructions) = self.visit_expression(&input.expression);
                 // Get the output type of the function.

compiler/passes/src/static_single_assignment/rename_expression.rs

@@ -19,7 +19,7 @@ use crate::StaticSingleAssigner;
 use leo_ast::{
     AccessExpression, AssociatedFunction, BinaryExpression, CallExpression, Expression, ExpressionConsumer, Identifier,
     Literal, MemberAccess, Statement, Struct, StructExpression, StructVariableInitializer, TernaryExpression,
-    TupleAccess, TupleExpression, UnaryExpression,
+    TupleAccess, TupleExpression, UnaryExpression, UnitExpression,
 };
 use leo_span::{sym, Symbol};
 
@@ -322,4 +322,8 @@ impl ExpressionConsumer for StaticSingleAssigner<'_> {
 
         (Expression::Identifier(place), statements)
     }
+
+    fn consume_unit(&mut self, input: UnitExpression) -> Self::Output {
+        (Expression::Unit(input), Default::default())
+    }
 }

compiler/passes/src/type_checking/check_expressions.rs

@@ -627,10 +627,7 @@ impl<'a> ExpressionVisitor<'a> for TypeChecker<'a> {
 
     fn visit_tuple(&mut self, input: &'a TupleExpression, expected: &Self::AdditionalInput) -> Self::Output {
         match input.elements.len() {
-            0 => {
+            0 => unreachable!("Tuple expressions must have at least one element."),
-                self.emit_err(TypeCheckerError::unit_tuple(input.span()));
-                None
-            }
             1 => {
                 self.emit_err(TypeCheckerError::singleton_tuple(input.span()));
                 None

tests/compiler/tuple/function_return_unit.leo

@@ -1,6 +1,6 @@
 /*
 namespace: Compile
-expectation: Fail
+expectation: Pass
 input_file:
  - inputs/bool_bool.in
 */

tests/expectations/compiler/tuple/assign_unit_fail.out

@@ -2,4 +2,4 @@
 namespace: Compile
 expectation: Fail
 outputs:
-  - "Error [ETYC0372054]: Empty tuple expressions and tuple types are not allowed.\n    --> compiler-test:7:9\n     |\n   7 |         let b: () = ();\n     |         ^^^^^^^^^^^^^^\nError [ETYC0372054]: Empty tuple expressions and tuple types are not allowed.\n    --> compiler-test:7:21\n     |\n   7 |         let b: () = ();\n     |                     ^^\nError [ETYC0372054]: Empty tuple expressions and tuple types are not allowed.\n    --> compiler-test:12:9\n     |\n  12 |         let b: () = bar();\n     |         ^^^^^^^^^^^^^^^^^\nError [ETYC0372048]: Cannot call a local transition function from a transition function.\n    --> compiler-test:12:21\n     |\n  12 |         let b: () = bar();\n     |                     ^^^^^\nError [ETYC0372006]: Call expected `1` args, but got `0`\n    --> compiler-test:12:21\n     |\n  12 |         let b: () = bar();\n     |                     ^^^^^\n"
+  - "Error [ETYC0372054]: Empty tuple expressions and tuple types are not allowed.\n    --> compiler-test:6:9\n     |\n   6 |         let b: () = ();\n     |         ^^^^^^^^^^^^^^\nError [ETYC0372054]: Empty tuple expressions and tuple types are not allowed.\n    --> compiler-test:11:9\n     |\n  11 |         let b: () = bar();\n     |         ^^^^^^^^^^^^^^^^^\nError [ETYC0372048]: Cannot call a local transition function from a transition function.\n    --> compiler-test:11:21\n     |\n  11 |         let b: () = bar();\n     |                     ^^^^^\nError [ETYC0372006]: Call expected `1` args, but got `0`\n    --> compiler-test:11:21\n     |\n  11 |         let b: () = bar();\n     |                     ^^^^^\n"

tests/expectations/compiler/tuple/function_return_nothing.out

@@ -0,0 +1,10 @@
+---
+namespace: Compile
+expectation: Pass
+outputs:
+  - output:
+      - initial_input_ast: 1a81fc79fbd61a51db3d300d5eb64e9108b60f0c83abecf946ab6a43aa05abee
+    initial_ast: 2b8b08ac0834c20e30e5aac2d39f2a1d60aef024587b62209708638986053de1
+    unrolled_ast: 2b8b08ac0834c20e30e5aac2d39f2a1d60aef024587b62209708638986053de1
+    ssa_ast: 2b8b08ac0834c20e30e5aac2d39f2a1d60aef024587b62209708638986053de1
+    flattened_ast: eaed8b8a1a24eb23ec384fbd27c885db1c2437a398c304bd2f9b6ed9de2e9fa5

tests/expectations/compiler/tuple/function_return_unit.out

@@ -1,5 +1,10 @@
 ---
 namespace: Compile
-expectation: Fail
+expectation: Pass
 outputs:
-  - "Error [ETYC0372054]: Empty tuple expressions and tuple types are not allowed.\n    --> compiler-test:5:16\n     |\n   5 |         return ();\n     |                ^^\n"
+  - output:
+      - initial_input_ast: ba75ac7ea183c8a86596b63c2dcc42bdc2d7a02cfa8f1d2e16f3c2c33bfe4f2e
+    initial_ast: 2b8b08ac0834c20e30e5aac2d39f2a1d60aef024587b62209708638986053de1
+    unrolled_ast: 2b8b08ac0834c20e30e5aac2d39f2a1d60aef024587b62209708638986053de1
+    ssa_ast: 2b8b08ac0834c20e30e5aac2d39f2a1d60aef024587b62209708638986053de1
+    flattened_ast: eaed8b8a1a24eb23ec384fbd27c885db1c2437a398c304bd2f9b6ed9de2e9fa5

tests/expectations/compiler/tuple/tuple_access.out

@@ -2,4 +2,9 @@
 namespace: Compile
 expectation: Pass
 outputs:
-  - "Error [ETYC0372058]: A function cannot take in tuples as input.\n    --> compiler-test:5:20\n     |\n   5 |     transition baz(a: (u8, u8)) -> u8 {\n     |                    ^\n"
+  - output:
+      - initial_input_ast: no input
+    initial_ast: a81aefbb2dc5b4c4bf25415c244be3c753794f27878087e513caf99a62eb2b6e
+    unrolled_ast: a81aefbb2dc5b4c4bf25415c244be3c753794f27878087e513caf99a62eb2b6e
+    ssa_ast: 3ef50f2cfca9dd0d0af10810aa4f7767f3adf8fd4c3f54f6d1c503901510a6b7
+    flattened_ast: 50f5304628172ecd7e6d19c53f4fc57a4df3f4e76df18152804f34f42ac81e7d

tests/expectations/compiler/tuple/tuple_in_assignment.out

@@ -0,0 +1,10 @@
+---
+namespace: Compile
+expectation: Pass
+outputs:
+  - output:
+      - initial_input_ast: no input
+    initial_ast: dd0977ae1402bb8fa7c3531c42389adc291dd730f3aacdd567dbdbef321e958a
+    unrolled_ast: dd0977ae1402bb8fa7c3531c42389adc291dd730f3aacdd567dbdbef321e958a
+    ssa_ast: f13ee06db150eecf24ef65504fb8b36f055a962c328b1c1fbb7bd15edc6050bd
+    flattened_ast: 7152760b06956005659ff36441463b342a22cc27ece042f8be4c60b82e933de0

tests/expectations/compiler/tuple/tuple_in_function_param.out

@@ -2,4 +2,4 @@
 namespace: Compile
 expectation: Fail
 outputs:
-  - "Error [ETYC0372058]: A function cannot take in tuples as input.\n    --> compiler-test:4:20\n     |\n   4 |     transition foo(a: (u8, u16)) -> (u8, u16) {\n     |                    ^\nError [ETYC0372058]: A function cannot take in tuples as input.\n    --> compiler-test:10:20\n     |\n  10 |     transition bar(a: (u8, (u8, u8))) -> (u8, (u8, u8)) {\n     |                    ^\nError [ETYC0372055]: A tuple type cannot contain a tuple.\n    --> compiler-test:10:47\n     |\n  10 |     transition bar(a: (u8, (u8, u8))) -> (u8, (u8, u8)) {\n     |                                               ^^^^^^^^\n"
+  - "Error [ETYC0372058]: A function cannot take in tuples as input.\n    --> compiler-test:4:20\n     |\n   4 |     transition foo(a: (u8, u16)) -> (u8, u16) {\n     |                    ^\n"

tests/expectations/compiler/tuple/tuple_in_record_fail.out

@@ -0,0 +1,5 @@
+---
+namespace: Compile
+expectation: Fail
+outputs:
+  - "Error [ETYC0372057]: A record cannot contain a tuple.\n    --> compiler-test:7:9\n     |\n   7 |         amounts: (u64, u64),\n     |         ^^^^^^^\n"

tests/expectations/compiler/tuple/tuple_in_return_type.out

@@ -0,0 +1,5 @@
+---
+namespace: Compile
+expectation: Fail
+outputs:
+  - "Error [ETYC0372055]: A tuple type cannot contain a tuple.\n    --> compiler-test:4:35\n     |\n   4 |     transition bar(a: u8) -> (u8, (u8, u8)) {\n     |                                   ^^^^^^^^\nError [ETYC0372060]: A tuple expression cannot contain another tuple expression.\n    --> compiler-test:5:20\n     |\n   5 |         return (a, (a + a, a * a));\n     |                    ^^^^^^^^^^^^^^\nError [ETYC0372060]: A tuple expression cannot contain another tuple expression.\n    --> compiler-test:5:20\n     |\n   5 |         return (a, (a + a, a * a));\n     |                    ^^^^^^^^^^^^^^\n"

tests/expectations/compiler/tuple/tuple_in_struct_fail.out

@@ -0,0 +1,5 @@
+---
+namespace: Compile
+expectation: Fail
+outputs:
+  - "Error [ETYC0372056]: A struct cannot contain a tuple.\n    --> compiler-test:5:9\n     |\n   5 |         mem: (u8, u16)\n     |         ^^^\nError [ETYC0372056]: A struct cannot contain a tuple.\n    --> compiler-test:9:9\n     |\n   9 |         mems: (A, A)\n     |         ^^^^\n"

tests/expectations/compiler/tuple/tuple_not_allowed_fail.out

@@ -0,0 +1,5 @@
+---
+namespace: Compile
+expectation: Fail
+outputs:
+  - "Error [ETYC0372056]: A struct cannot contain a tuple.\n    --> compiler-test:22:9\n     |\n  22 |         mem: (u8, u16)\n     |         ^^^\nError [ETYC0372058]: A function cannot take in tuples as input.\n    --> compiler-test:8:18\n     |\n   8 |     function foo(a: (u8, u16)) -> (u8, u16) {\n     |                  ^\nError [ETYC0372055]: A tuple type cannot contain a tuple.\n    --> compiler-test:12:28\n     |\n  12 |     function bar() -> (u8, (u16, u32)) {\n     |                            ^^^^^^^^^^\nError [ETYC0372060]: A tuple expression cannot contain another tuple expression.\n    --> compiler-test:13:22\n     |\n  13 |         return (1u8, (2u16, 3u32));\n     |                      ^^^^^^^^^^^^\nError [ETYC0372060]: A tuple expression cannot contain another tuple expression.\n    --> compiler-test:13:22\n     |\n  13 |         return (1u8, (2u16, 3u32));\n     |                      ^^^^^^^^^^^^\nError [ETYC0372007]: Expected one type from `i8, i16, i32, i64, i128, u8, u16, u32, u64, u128`, but got `(u8,u16)`\n    --> compiler-test:17:13\n     |\n  17 |         for i: (u8, u16) in 0u8..2u8 {}\n     |             ^\nError [ETYC0372003]: Expected type `(u8,u16)` but type `u8` was found\n    --> compiler-test:17:29\n     |\n  17 |         for i: (u8, u16) in 0u8..2u8 {}\n     |                             ^^^\nError [ETYC0372003]: Expected type `(u8,u16)` but type `u8` was found\n    --> compiler-test:17:34\n     |\n  17 |         for i: (u8, u16) in 0u8..2u8 {}\n     |                                  ^^^\n"