Relax restrictions on immutable initialization

test/libsolidity/semanticTests/immutable/delete.sol

@@ -0,0 +1,15 @@
+contract C {
+    uint8 immutable public a;
+    uint8 immutable public b = 0x42;
+    uint public c;
+
+    constructor() {
+        delete a;
+        delete b;
+        c = b * 2 + a;
+    }
+}
+// ----
+// a() -> 0
+// b() -> 0
+// c() -> 0

test/libsolidity/semanticTests/immutable/increment_decrement.sol

@@ -0,0 +1,18 @@
+contract C {
+    int immutable x = 1;
+    int immutable y = 3;
+
+    constructor() {
+        x--;
+        --x;
+        y++;
+        ++y;
+        --y;
+    }
+
+    function f() public view returns (int, int) {
+        return (x, y);
+    }
+}
+// ----
+// f() -> -1, 4

test/libsolidity/semanticTests/immutable/multiple_initializations.sol

@@ -0,0 +1,27 @@
+contract A {
+    uint immutable x = x + 1;
+    uint immutable y = x += 2;
+
+    constructor(uint) m(x += 16) m(x += 32) {
+        x += 64;
+        x += 128;
+    }
+
+    modifier m(uint) {
+        _;
+    }
+
+    function get() public returns (uint) {
+        return x;
+    }
+}
+
+contract B is A(A.x += 8) {
+    constructor(uint) {}
+}
+
+contract C is B {
+    constructor() B(x += 4) {}
+}
+// ----
+// get() -> 0xff

test/libsolidity/semanticTests/immutable/uninitialized.sol

@@ -0,0 +1,11 @@
+contract C {
+    uint immutable u;
+    bool immutable b;
+    address immutable a;
+
+    function get() public returns (uint, bool, address) {
+        return (u, b, a);
+    }
+}
+// ----
+// get() -> 0, false, 0x0

test/libsolidity/syntaxTests/immutable/conditional_return_uninitialized.sol

@@ -7,5 +7,3 @@ contract C {
         x = 1;
     }
 }
-// ----
-// TypeError 2658: (86-93): Construction control flow ends without initializing all immutable state variables.

test/libsolidity/syntaxTests/immutable/conditionally_initialized.sol

@@ -5,5 +5,3 @@ contract C {
             x = 1;
     }
 }
-// ----
-// TypeError 4599: (86-87): Cannot write to immutable here: Immutable variables cannot be initialized inside an if statement.

test/libsolidity/syntaxTests/immutable/ctor_initialization_indirect_reading.sol

@@ -6,5 +6,3 @@ contract C {
 
     function f() public view returns (uint) { return 3 + x; }
 }
-// ----
-// TypeError 7733: (136-137): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/ctor_initialization_reading.sol

@@ -4,5 +4,3 @@ contract C {
         x = 3 + x;
     }
 }
-// ----
-// TypeError 7733: (71-72): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/ctor_modifier_args.sol

@@ -9,4 +9,3 @@ contract C {
     function f(uint a) internal pure {}
 }
 // ----
-// TypeError 1581: (59-60): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/ctor_modifier_reading.sol

@@ -10,5 +10,3 @@ contract C {
 
     function f(uint a) internal pure {}
 }
-// ----
-// TypeError 7733: (119-120): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/decrement.sol

@@ -4,5 +4,3 @@ contract C {
         x--;
     }
 }
-// ----
-// TypeError 3969: (63-64): Immutable variables must be initialized using an assignment.

test/libsolidity/syntaxTests/immutable/delete.sol

@@ -1,8 +0,0 @@
-contract C {
-    uint immutable x;
-    constructor() {
-        delete x;
-    }
-}
-// ----
-// TypeError 3969: (70-71): Immutable variables must be initialized using an assignment.

test/libsolidity/syntaxTests/immutable/delete_and_initialize.sol

@@ -1,8 +0,0 @@
-contract C {
-    uint immutable x = 3;
-    constructor() {
-        delete x;
-    }
-}
-// ----
-// TypeError 2718: (74-75): Immutable variables cannot be modified after initialization.

test/libsolidity/syntaxTests/immutable/function_initialization_reading.sol

@@ -3,5 +3,3 @@ contract C {
 
     function f() public view returns (uint) { return 3 + x; }
 }
-// ----
-// TypeError 7733: (99-100): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/function_pointer_initializing.sol

@@ -11,4 +11,3 @@ contract C is B(C.f) {
 }
 // ----
 // TypeError 1581: (200-201): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.
-// TypeError 1574: (109-110): Immutable state variable already initialized.

test/libsolidity/syntaxTests/immutable/function_pointer_reading.sol

@@ -10,4 +10,3 @@ contract C is B(C.f) {
     function f() internal view returns(uint) { return x + 2; }
 }
 // ----
-// TypeError 7733: (205-206): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/increment.sol

@@ -4,5 +4,3 @@ contract C {
         x++;
     }
 }
-// ----
-// TypeError 3969: (63-64): Immutable variables must be initialized using an assignment.

test/libsolidity/syntaxTests/immutable/increment_decrement.sol

@@ -1,11 +0,0 @@
-contract C {
-  uint immutable x;
-  uint immutable y;
-  constructor() {
-    ++x;
-    --y;
-  }
-}
-// ----
-// TypeError 3969: (77-78): Immutable variables must be initialized using an assignment.
-// TypeError 3969: (86-87): Immutable variables must be initialized using an assignment.

test/libsolidity/syntaxTests/immutable/indirect_reading_during_statevar_init.sol

@@ -5,4 +5,3 @@ contract C {
     function f() internal pure returns(uint) { return x; }
 }
 // ----
-// TypeError 7733: (112-113): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/inheritance_ctor_argument.sol

@@ -10,5 +10,3 @@ contract C is B {
     uint immutable y;
     constructor() B(y = 3) { }
 }
-// ----
-// TypeError 1581: (148-149): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/inheritance_ctor_inherit_specifier_argument_init.sol

@@ -9,5 +9,3 @@ contract B {
 contract C is B(C.y = 3) {
     uint immutable y;
 }
-// ----
-// TypeError 1581: (104-107): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/inheritance_ctor_inherit_specifier_argument_reading.sol

@@ -12,5 +12,3 @@ contract C is B(C.y) {
         y = 3;
     }
 }
-// ----
-// TypeError 7733: (104-107): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/inheritance_virtual_functions.sol

@@ -16,4 +16,3 @@ contract C is B {
     }
 }
 // ----
-// TypeError 7733: (263-264): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/inheritance_virtual_modifiers.sol

@@ -17,5 +17,3 @@ contract C is B {
         _; f(x);
     }
 }
-// ----
-// TypeError 7733: (245-246): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/inheritance_wrong_ctor.sol

@@ -7,5 +7,3 @@ contract C is B {
         x = 3;
     }
 }
-// ----
-// TypeError 7484: (88-89): Cannot write to immutable here: Immutable variables must be initialized in the constructor of the contract they are defined in.

test/libsolidity/syntaxTests/immutable/init_in_constructor_modifier_param.sol

@@ -4,4 +4,3 @@ contract D {
     constructor() m(t = 2) {}
 }
 // ----
-// TypeError 1581: (83-84): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/init_in_ctor_param.sol

@@ -3,5 +3,3 @@ contract D is C {
   uint immutable t;
   constructor() C(t=2) {}
 }
-// ----
-// TypeError 1581: (92-93): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/init_in_function_modifier_param.sol

@@ -0,0 +1,7 @@
+contract D {
+    uint immutable t;
+    modifier m(uint) { _; }
+    function f() public m(t = 2) {}
+}
+// ----
+// TypeError 1581: (89-90): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/init_in_function_via_contract_name.sol

@@ -0,0 +1,11 @@
+contract B {
+    uint immutable x;
+}
+
+contract C is B {
+    function f() public {
+        B.x = 42;
+    }
+}
+// ----
+// TypeError 1581: (90-93): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/init_in_function_via_super.sol

@@ -0,0 +1,13 @@
+contract B {
+    uint immutable x;
+
+    function g() public {}
+}
+
+contract C is B {
+    function f() public {
+        super.x = 42;
+    }
+}
+// ----
+// TypeError 9582: (118-125): Member "x" not found or not visible after argument-dependent lookup in type(contract super C).

test/libsolidity/syntaxTests/immutable/init_in_inheritance_specifier_param.sol

@@ -2,5 +2,3 @@ contract C { constructor(uint) {} }
 contract D is C(D.t = 2) {
     uint immutable t;
 }
-// ----
-// TypeError 1581: (52-55): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/loop_initialized.sol

@@ -5,5 +5,3 @@ contract C {
             x = 1;
     }
 }
-// ----
-// TypeError 6672: (88-89): Cannot write to immutable here: Immutable variables cannot be initialized inside a loop.

test/libsolidity/syntaxTests/immutable/multiple_inheritance_virtual_functions.sol

@@ -26,4 +26,3 @@ contract C is A, B {
     }
 }
 // ----
-// TypeError 7733: (499-500): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/multiple_inheritance_virtual_functions_with_super.sol

@@ -26,4 +26,3 @@ contract C is A, B {
     }
 }
 // ----
-// TypeError 7733: (503-504): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/multiple_initializations.sol

@@ -5,5 +5,3 @@ contract C {
         x = 4;
     }
 }
-// ----
-// TypeError 1574: (78-79): Immutable state variable already initialized.

test/libsolidity/syntaxTests/immutable/private_state_var.sol

@@ -16,5 +16,3 @@ contract C is B {
     function f() internal view override returns(uint) { return readX(); }
 
 }
-// ----
-// TypeError 7733: (202-203): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/read_in_function_before_init.sol

@@ -8,5 +8,3 @@ contract B is A {
 	uint immutable x = 2;
 	function f() override pure internal returns (uint) { return x; }
 }
-// ----
-// TypeError 7733: (223-224): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/read_in_function_before_init2.sol

@@ -3,5 +3,3 @@ contract C {
   uint x = f();
   function f() internal pure returns (uint) { return t; }
 }
-// ----
-// TypeError 7733: (106-107): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/reading_after_initialization_function.sol

@@ -13,4 +13,3 @@ contract C {
 	}
 }
 // ----
-// TypeError 7733: (141-142): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/reading_during_statevar_init.sol

@@ -2,5 +2,3 @@ contract C {
     uint immutable x = 0;
     uint y = x;
 }
-// ----
-// TypeError 7733: (52-53): Immutable variables cannot be read before they are initialized.

test/libsolidity/syntaxTests/immutable/return_uninitialized.sol

@@ -7,4 +7,4 @@ contract C {
     }
 }
 // ----
-// TypeError 2658: (63-70): Construction control flow ends without initializing all immutable state variables.
+// Warning 5740: (80-85): Unreachable code.

test/libsolidity/syntaxTests/immutable/state_var_external_access_read.sol

@@ -0,0 +1,13 @@
+contract C {
+    uint immutable public x = 42;
+
+    function g() external view returns (uint) {}
+
+    function f() public view returns (uint) {
+        return this.x();
+    }
+
+    function h() public view returns (function () external view returns (uint)) {
+        return this.x;
+    }
+}

test/libsolidity/syntaxTests/immutable/state_var_external_access_write.sol

@@ -0,0 +1,11 @@
+contract C {
+    uint immutable public x = 42;
+
+    function g() external view returns (uint) {}
+
+    function f() public view {
+        this.x = this.g;
+    }
+}
+// ----
+// TypeError 4247: (137-143): Expression has to be an lvalue.

test/libsolidity/syntaxTests/immutable/try_catch_initialized.sol

@@ -33,9 +33,3 @@ contract B
 }
 // ====
 // EVMVersion: >=byzantium
-// ----
-// TypeError 4130: (108-116): Cannot write to immutable here: Immutable variables cannot be initialized inside a try/catch statement.
-// TypeError 4130: (144-152): Cannot write to immutable here: Immutable variables cannot be initialized inside a try/catch statement.
-// TypeError 4130: (216-224): Cannot write to immutable here: Immutable variables cannot be initialized inside a try/catch statement.
-// TypeError 4130: (297-305): Cannot write to immutable here: Immutable variables cannot be initialized inside a try/catch statement.
-// TypeError 4130: (357-365): Cannot write to immutable here: Immutable variables cannot be initialized inside a try/catch statement.

test/libsolidity/syntaxTests/immutable/uninitialized.sol

@@ -1,5 +1,3 @@
 contract C {
     uint immutable x;
 }
-// ----
-// TypeError 2658: (0-36): Construction control flow ends without initializing all immutable state variables.

test/libsolidity/syntaxTests/immutable/uninitialized_private_state_var.sol

@@ -16,6 +16,3 @@ contract C is B {
     function f() internal view override returns(uint) { return readX(); }
 
 }
-// ----
-// TypeError 2658: (0-202): Construction control flow ends without initializing all immutable state variables.
-// TypeError 2658: (204-361): Construction control flow ends without initializing all immutable state variables.

test/libsolidity/syntaxTests/immutable/variable_declaration_already.sol

@@ -3,6 +3,3 @@ contract C {
     uint immutable x = z = y = 3;
     uint immutable y = 5;
 }
-// ----
-// TypeError 1581: (66-67): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.
-// TypeError 1581: (62-63): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.

test/libsolidity/syntaxTests/immutable/variable_declaration_value.sol

@@ -1,5 +1,3 @@
 contract C {
     int immutable x = x = 5;
 }
-// ----
-// TypeError 1581: (35-36): Cannot write to immutable here: Immutable variables can only be initialized inline or assigned directly in the constructor.