Contract level checker: Disallow free function redefinition and alias

shadowing another free function

Co-authored-by: chriseth <chris@ethereum.org>

test/libsolidity/semanticTests/freeFunctions/free_namesake_contract_function.sol

@@ -0,0 +1,10 @@
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function f() public pure returns (uint) {
+    return f();
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// f() -> FAILURE

test/libsolidity/semanticTests/multiSource/circular_import.sol

@@ -0,0 +1,15 @@
+==== Source: s1.sol ====
+import {f as g} from "s2.sol";
+function f() pure returns (uint) { return 1; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+contract C {
+  function foo() public pure returns (uint) {
+    return f() - g();
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// foo() -> 1

test/libsolidity/semanticTests/multiSource/circular_import_2.sol

@@ -0,0 +1,14 @@
+==== Source: s1.sol ====
+import {f as g, g as h} from "s2.sol";
+function f() pure returns (uint) { return h() - g(); }
+==== Source: s2.sol ====
+import {f as h} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+function g() pure returns (uint) { return 4; }
+contract C {
+  function foo() public pure returns (uint) {
+    return h() - f() - g();
+  }
+}
+// ----
+// foo() -> -4

test/libsolidity/semanticTests/multiSource/circular_reimport.sol

@@ -0,0 +1,16 @@
+==== Source: s1.sol ====
+import {f as g, g as h} from "s2.sol";
+function f() pure returns (uint) { return h() - g(); }
+==== Source: s2.sol ====
+import {f as h} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+function g() pure returns (uint) { return 4; }
+==== Source: s3.sol ====
+import "s1.sol";
+contract C {
+  function foo() public pure returns (uint) {
+    return f() - g() - h();
+  }
+}
+// ----
+// foo() -> -4

test/libsolidity/semanticTests/multiSource/circular_reimport_2.sol

@@ -0,0 +1,16 @@
+==== Source: s1.sol ====
+import {f as g, g as h} from "s2.sol";
+function f() pure returns (uint) { return h() - g(); }
+==== Source: s2.sol ====
+import {f as h} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+function g() pure returns (uint) { return 4; }
+==== Source: s3.sol ====
+import "s2.sol";
+contract C {
+  function foo() public pure returns (uint) {
+    return f() - g() - h();
+  }
+}
+// ----
+// foo() -> -4

test/libsolidity/semanticTests/multiSource/free_different_interger_types.sol

@@ -0,0 +1,14 @@
+==== Source: s1.sol ====
+function f(uint24) pure returns (uint) { return 24; }
+function g(bool) pure returns (bool) { return true; }
+==== Source: s2.sol ====
+import {f as g, g as g} from "s1.sol";
+contract C {
+  function foo() public pure returns (uint, bool) {
+    return (g(2), g(false));
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// foo() -> 24, true

test/libsolidity/semanticTests/multiSource/free_function_resolution_base_contract.sol

@@ -0,0 +1,18 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function g() public pure returns (uint) {
+    return f();
+  }
+}
+==== Source: s2.sol ====
+import "s1.sol";
+contract D is C {
+  function h() public pure returns (uint) {
+    return g();
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// h() -> 1337

test/libsolidity/semanticTests/multiSource/free_function_resolution_override_virtual.sol

@@ -0,0 +1,18 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function g() public pure virtual returns (uint) {
+    return f() + 1;
+  }
+}
+==== Source: s2.sol ====
+import "s1.sol";
+contract D is C {
+  function g() public pure override returns (uint) {
+    return f();
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// g() -> 1337

test/libsolidity/semanticTests/multiSource/free_function_resolution_override_virtual_super.sol

@@ -0,0 +1,18 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function g() public pure virtual returns (uint) {
+    return f();
+  }
+}
+==== Source: s2.sol ====
+import "s1.sol";
+contract D is C {
+  function g() public pure override returns (uint) {
+    return super.g();
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// g() -> 1337

test/libsolidity/semanticTests/multiSource/free_function_resolution_override_virtual_transitive.sol

@@ -0,0 +1,25 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function g() public pure virtual returns (uint) {
+    return f();
+  }
+}
+==== Source: s2.sol ====
+import "s1.sol";
+contract D is C {
+  function g() public pure virtual override returns (uint) {
+    return super.g() + 1;
+  }
+}
+==== Source: s3.sol ====
+import "s2.sol";
+contract E is D {
+  function g() public pure override returns (uint) {
+    return super.g() + 1;
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// g() -> 1339

test/libsolidity/semanticTests/multiSource/free_function_transitive_import.sol

@@ -0,0 +1,27 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function g() public pure returns (uint) {
+    return f();
+  }
+}
+==== Source: s2.sol ====
+import "s1.sol";
+contract D is C {
+  function h() public pure returns (uint) {
+    return g();
+  }
+}
+==== Source: s3.sol ====
+import "s2.sol";
+import {f as f} from "s2.sol";
+contract E is D {
+  function i() public pure returns (uint) {
+    return f();
+  }
+}
+
+// ====
+// compileViaYul: also
+// ----
+// i() -> 1337

test/libsolidity/semanticTests/multiSource/imported_free_function_via_alias.sol

@@ -0,0 +1,19 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function g() public pure virtual returns (uint) {
+    return f();
+  }
+}
+==== Source: s2.sol ====
+import "s1.sol" as M;
+function f() pure returns (uint) { return 6; }
+contract D is M.C {
+  function g() public pure override returns (uint) {
+    return super.g() + f() * 10000;
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// g() -> 61337

test/libsolidity/semanticTests/multiSource/imported_free_function_via_alias_direct_call.sol

@@ -0,0 +1,14 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+function f() pure returns (uint) { return 6; }
+contract D {
+  function h() public pure returns (uint) {
+    return g() + f() * 10000;
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// h() -> 61337

test/libsolidity/semanticTests/multiSource/reimport_imported_function.sol

@@ -0,0 +1,15 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+==== Source: s3.sol ====
+import {g as h} from "s2.sol";
+contract C {
+  function foo() public pure returns (uint) {
+    return h();
+  }
+}
+// ====
+// compileViaYul: also
+// ----
+// foo() -> 1337

test/libsolidity/syntaxTests/freeFunctions/free_different_integer_types.sol

@@ -0,0 +1,4 @@
+function f(uint24) {}
+function f(uint16) {}
+function f(int24) {}
+function f(bool) {}

test/libsolidity/syntaxTests/freeFunctions/free_function_namesake_different_parameter_types.sol

@@ -0,0 +1,11 @@
+function g() pure returns (uint) { return 1; }
+function g() pure returns (string memory) { return "1"; }
+contract C {
+  function foo() public pure returns (uint) {
+    string memory s = g();
+    return 100/g();
+  }
+}
+// ----
+// DeclarationError 1686: (0-46): Function with same name and parameter types defined twice.
+// TypeError 9574: (168-189): Type uint256 is not implicitly convertible to expected type string memory.

test/libsolidity/syntaxTests/freeFunctions/free_identical.sol

@@ -0,0 +1,4 @@
+function f() pure returns (uint) { return 1337; }
+function f() pure returns (uint) { return 42; }
+// ----
+// DeclarationError 1686: (0-49): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/freeFunctions/free_identical_multiple.sol

@@ -0,0 +1,5 @@
+function f() pure returns (uint) { return 1337; }
+function f() pure returns (uint) { return 42; }
+function f() pure returns (uint) { return 1; }
+// ----
+// DeclarationError 1686: (0-49): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/freeFunctions/free_namesake_contract_function.sol

@@ -0,0 +1,8 @@
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function f() public pure returns (uint) {
+    return f();
+  }
+}
+// ----
+// Warning 2519: (65-126): This declaration shadows an existing declaration.

test/libsolidity/syntaxTests/freeFunctions/free_redefinition.sol

@@ -0,0 +1,9 @@
+function f() pure returns (uint) { return 1337; }
+function f() view returns (uint) { return 42; }
+contract C {
+  function g() public pure virtual returns (uint) {
+    return f();
+  }
+}
+// ----
+// DeclarationError 1686: (0-49): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/alias_shadows_another_alias.sol

@@ -0,0 +1,19 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+function g() pure returns (uint) { return 42; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+==== Source: s3.sol ====
+// imports f()->1337 as g()
+import "s2.sol";
+// imports f()->1337 as f() and
+// g()->42 as g
+import {f as f, g as g} from "s1.sol";
+contract C {
+  function foo() public pure returns (uint) {
+    // calls f()->1337 / f()->1337
+    return f() / g();
+  }
+}
+// ----
+// DeclarationError 1686: (s1.sol:0-49): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/alias_shadows_function.sol

@@ -0,0 +1,19 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+function g() pure returns (uint) { return 42; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+==== Source: s3.sol ====
+// imports f()->1337 as g()
+import "s2.sol";
+// imports f()->1337 as f() and
+// g()->42 as g
+import "s1.sol";
+contract C {
+  function foo() public pure returns (uint) {
+    // calls f()->1337 / f()->1337
+    return f() / g();
+  }
+}
+// ----
+// DeclarationError 1686: (s1.sol:0-49): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/circular_import.sol

@@ -0,0 +1,6 @@
+==== Source: s1.sol ====
+import {f as g} from "s2.sol";
+function f() pure returns (uint) { return 1; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+function f() pure returns (uint) { return 2; }

test/libsolidity/syntaxTests/multiSource/circular_import_2.sol

@@ -0,0 +1,7 @@
+==== Source: s1.sol ====
+import {f as g, g as h} from "s2.sol";
+function f() pure returns (uint) { return h() - g(); }
+==== Source: s2.sol ====
+import {f as h} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+function g() pure returns (uint) { return 4; }

test/libsolidity/syntaxTests/multiSource/circular_import_3.sol

@@ -0,0 +1,14 @@
+==== Source: s1.sol ====
+import {f as g, g as h} from "s2.sol";
+function f() pure returns (uint) { return h() - g(); }
+==== Source: s2.sol ====
+import {f as h} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+function g() pure returns (uint) { return 4; }
+==== Source: s3.sol ====
+import "s1.sol";
+import "s2.sol";
+// ----
+// DeclarationError 1686: (s1.sol:39-93): Function with same name and parameter types defined twice.
+// DeclarationError 1686: (s2.sol:31-77): Function with same name and parameter types defined twice.
+// DeclarationError 1686: (s2.sol:78-124): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/circular_import_4.sol

@@ -0,0 +1,9 @@
+==== Source: s1.sol ====
+import {f as g, g as h} from "s2.sol";
+function f() pure returns (uint) { return h() - g(); }
+==== Source: s2.sol ====
+import {f as h} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+function g() pure returns (uint) { return 4; }
+==== Source: s3.sol ====
+import "s1.sol";

test/libsolidity/syntaxTests/multiSource/circular_import_5.sol

@@ -0,0 +1,9 @@
+==== Source: s1.sol ====
+import {f as g, g as h} from "s2.sol";
+function f() pure returns (uint) { return h() - g(); }
+==== Source: s2.sol ====
+import {f as h} from "s1.sol";
+function f() pure returns (uint) { return 2; }
+function g() pure returns (uint) { return 4; }
+==== Source: s3.sol ====
+import "s2.sol";

test/libsolidity/syntaxTests/multiSource/duplicate_import_statement.sol

@@ -0,0 +1,10 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+==== Source: s2.sol ====
+import {f as f} from "s1.sol";
+import {f as f} from "s1.sol";
+contract C {
+  function g() public pure returns (uint) {
+    return f();
+  }
+}

test/libsolidity/syntaxTests/multiSource/free_different_interger_types.sol

@@ -0,0 +1,10 @@
+==== Source: s1.sol ====
+function f(uint) pure returns (uint) { return 24; }
+function g() pure returns (bool) { return true; }
+==== Source: s2.sol ====
+import {f as g, g as g} from "s1.sol";
+contract C {
+  function foo() public pure returns (uint, bool) {
+    return (g(2), g());
+  }
+}

test/libsolidity/syntaxTests/multiSource/free_function_alias_different_parameter_types.sol

@@ -0,0 +1,19 @@
+==== Source: s1.sol ====
+function f() pure returns (uint16) { return 1337; }
+function g() pure returns (uint8) { return 42; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+==== Source: s3.sol ====
+// imports f(uint16)->1337 as g(uint16)
+import "s2.sol";
+// imports f(uint16)->1337 as f(uint16) and
+// g(uint8)->42 as g(uint8)
+import {f as f, g as g} from "s1.sol";
+contract C {
+  function foo() public pure returns (uint) {
+    // calls f()->1337 / f()->1337
+    return f() / g();
+  }
+}
+// ----
+// DeclarationError 1686: (s1.sol:0-51): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/free_function_redefinition_base_derived.sol

@@ -0,0 +1,9 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {}
+==== Source: s2.sol ====
+import "s1.sol";
+function f() pure returns (uint) { return 42; }
+contract D is C {}
+// ----
+// DeclarationError 1686: (s2.sol:17-64): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/free_function_redefinition_transitive.sol

@@ -0,0 +1,12 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {}
+==== Source: s2.sol ====
+import "s1.sol";
+contract D is C {}
+==== Source: s3.sol ====
+import "s2.sol";
+function f() pure returns (uint) { return 42; }
+contract E is D {}
+// ----
+// DeclarationError 1686: (s3.sol:17-64): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/free_function_resolution_override_virtual.sol

@@ -0,0 +1,19 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+contract C {
+  function f() public pure virtual returns (uint) {
+    return f();
+  }
+}
+==== Source: s2.sol ====
+import "s1.sol";
+function f() pure returns (uint) { return 42; }
+contract D is C {
+  function f() public pure override returns (uint) {
+    return f();
+  }
+}
+// ----
+// Warning 2519: (s1.sol:65-134): This declaration shadows an existing declaration.
+// Warning 2519: (s2.sol:85-155): This declaration shadows an existing declaration.
+// DeclarationError 1686: (s2.sol:17-64): Function with same name and parameter types defined twice.

test/libsolidity/syntaxTests/multiSource/import_contract_function_error.sol

@@ -0,0 +1,10 @@
+==== Source: s1.sol ====
+contract C {
+  function f() public pure returns (uint) {
+    return 1337;
+  }
+}
+==== Source: s2.sol ====
+import {C.f as g} from "s1.sol";
+// ----
+// ParserError 2314: (s2.sol:9-10): Expected '}' but got '.'

test/libsolidity/syntaxTests/multiSource/imported_free_function.sol

@@ -0,0 +1,9 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+==== Source: s2.sol ====
+import "s1.sol";
+contract C {
+  function g() public pure returns (uint) {
+    return f();
+  }
+}

test/libsolidity/syntaxTests/multiSource/multiple_imports_same_function.sol

@@ -0,0 +1,9 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+==== Source: s2.sol ====
+import {f as f, f as f, f as f} from "s1.sol";
+contract C {
+  function g() public pure returns (uint) {
+    return f();
+  }
+}

test/libsolidity/syntaxTests/multiSource/reimport_imported_function.sol

@@ -0,0 +1,11 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+==== Source: s2.sol ====
+import {f as g} from "s1.sol";
+==== Source: s3.sol ====
+import {g as h} from "s2.sol";
+contract C {
+  function foo() public pure returns (uint) {
+    return h();
+  }
+}

test/libsolidity/syntaxTests/multiSource/two_imports_same_function.sol

@@ -0,0 +1,9 @@
+==== Source: s1.sol ====
+function f() pure returns (uint) { return 1337; }
+==== Source: s2.sol ====
+import {f as f, f as f} from "s1.sol";
+contract C {
+  function g() public pure returns (uint) {
+    return f();
+  }
+}