checker: disallow import names and import aliases, shadowing the module name (#18431)

vlib/crypto/hmac/hmac_test.v

@@ -1,7 +1,6 @@
 // tests are taken from https://tools.ietf.org/html/rfc2202
 module hmac
 
-import crypto.hmac
 import crypto.md5
 import crypto.sha1
 import crypto.sha256
@@ -67,7 +66,7 @@ fn test_hmac_md5() {
 	]
 	mut result := ''
 	for i, key in hmac.keys {
-		result = hmac.new(key, hmac.data[i], md5.sum, md5.block_size).hex()
+		result = new(key, hmac.data[i], md5.sum, md5.block_size).hex()
 		assert result == md5_expected_results[i]
 	}
 }
@@ -84,7 +83,7 @@ fn test_hmac_sha1() {
 	]
 	mut result := ''
 	for i, key in hmac.keys {
-		result = hmac.new(key, hmac.data[i], sha1.sum, sha1.block_size).hex()
+		result = new(key, hmac.data[i], sha1.sum, sha1.block_size).hex()
 		assert result == sha1_expected_results[i]
 	}
 }
@@ -101,7 +100,7 @@ fn test_hmac_sha224() {
 	]
 	mut result := ''
 	for i, key in hmac.keys {
-		result = hmac.new(key, hmac.data[i], sha256.sum224, sha256.block_size).hex()
+		result = new(key, hmac.data[i], sha256.sum224, sha256.block_size).hex()
 		assert result == sha224_expected_results[i]
 	}
 }
@@ -118,7 +117,7 @@ fn test_hmac_sha256() {
 	]
 	mut result := ''
 	for i, key in hmac.keys {
-		result = hmac.new(key, hmac.data[i], sha256.sum, sha256.block_size).hex()
+		result = new(key, hmac.data[i], sha256.sum, sha256.block_size).hex()
 		assert result == sha256_expected_results[i]
 	}
 }
@@ -135,7 +134,7 @@ fn test_hmac_sha384() {
 	]
 	mut result := ''
 	for i, key in hmac.keys {
-		result = hmac.new(key, hmac.data[i], sha512.sum384, sha512.block_size).hex()
+		result = new(key, hmac.data[i], sha512.sum384, sha512.block_size).hex()
 		assert result == sha384_expected_results[i]
 	}
 }
@@ -152,7 +151,7 @@ fn test_hmac_sha512() {
 	]
 	mut result := ''
 	for i, key in hmac.keys {
-		result = hmac.new(key, hmac.data[i], sha512.sum512, sha512.block_size).hex()
+		result = new(key, hmac.data[i], sha512.sum512, sha512.block_size).hex()
 		assert result == sha512_expected_results[i]
 	}
 }
@@ -162,10 +161,10 @@ fn test_hmac_equal() {
 	mac1_2 := '7641c48a3b4aa8f887c07b3e83f96affb89c978fed8c96fcbbf4ad596eebfe496f9f16da6cd080ba393c6f365ad72b50d15c71bfb1d6b81f66a911786c6ce932'.bytes()
 	mac2_1 := '164b7a7bfcf819e2e395fbe73b56e0a387bd64222e831fd610270cd7ea2505549758bf75c05a994a6d034f65f8f0e6fdcaeab1a34d4a6b4b636e070a38bce737'.bytes()
 	mac2_2 := '164b7a7bfcf819e2e395fbe73b56e0a387bd64222e831fd610270cd7ea2505549758bf75c05a994a6d034f65f8f0e6fdcaeab1a34d4a6b4b636e070a38bce737'.bytes()
-	assert hmac.equal(mac1_1, mac1_2)
-	assert hmac.equal(mac2_1, mac2_2)
-	assert !hmac.equal(mac1_1, mac2_1)
-	assert !hmac.equal(mac1_1, mac2_2)
+	assert equal(mac1_1, mac1_2)
+	assert equal(mac2_1, mac2_2)
+	assert !equal(mac1_1, mac2_1)
+	assert !equal(mac1_1, mac2_2)
 }
 
 // not yet supported by crypto module

vlib/v/checker/checker.v

@@ -169,6 +169,20 @@ pub fn (mut c Checker) check(ast_file_ &ast.File) {
 	c.reset_checker_state_at_start_of_new_file()
 	c.change_current_file(ast_file)
 	for i, ast_import in ast_file.imports {
+		// Imports with the same path and name (self-imports and module name conflicts with builtin module imports)
+		if c.mod == ast_import.mod {
+			c.error('cannot import `${ast_import.mod}` into a module with the same name',
+				ast_import.mod_pos)
+		}
+		// Duplicates of regular imports with the default alias (modname) and `as` imports with a custom alias
+		if c.mod == ast_import.alias {
+			if c.mod == ast_import.mod.all_after_last('.') {
+				c.error('cannot import `${ast_import.mod}` into a module with the same name',
+					ast_import.mod_pos)
+			}
+			c.error('cannot import `${ast_import.mod}` as `${ast_import.alias}` into a module with the same name',
+				ast_import.alias_pos)
+		}
 		for sym in ast_import.syms {
 			full_name := ast_import.mod + '.' + sym.name
 			if full_name in c.const_names {

vlib/v/checker/tests/import_mod_as_duplicate_err.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/import_mod_as_duplicate_err.vv:3:16: error: cannot import `json` as `json2` into a module with the same name
+    1 | module json2
+    2 | 
+    3 | import json as json2
+      |                ~~~~~
+    4 | 
+    5 | const used = true
+vlib/v/checker/tests/import_mod_as_duplicate_err.vv:1:1: error: project must include a `main` module or be a shared library (compile with `v -shared`)
+    1 | module json2
+      | ^
+    2 | 
+    3 | import json as json2

vlib/v/checker/tests/import_mod_as_duplicate_err.vv

@@ -0,0 +1,7 @@
+module json2
+
+import json as json2
+
+const used = true
+
+println(json2.used)

vlib/v/checker/tests/import_mod_duplicate_as_sub_err.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/import_mod_duplicate_as_sub_err.vv:3:8: error: cannot import `json` into a module with the same name
+    1 | module json
+    2 | 
+    3 | import json as vjson
+      |        ~~~~
+    4 | 
+    5 | const used = true
+vlib/v/checker/tests/import_mod_duplicate_as_sub_err.vv:1:1: error: project must include a `main` module or be a shared library (compile with `v -shared`)
+    1 | module json
+      | ^
+    2 | 
+    3 | import json as vjson

vlib/v/checker/tests/import_mod_duplicate_as_sub_err.vv

@@ -0,0 +1,8 @@
+module json
+
+import json as vjson
+
+const used = true
+
+println(json.used)
+println(vjson.used)

vlib/v/checker/tests/import_mod_duplicate_err.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/import_mod_duplicate_err.vv:3:8: error: cannot import `json` into a module with the same name
+    1 | module json
+    2 | 
+    3 | import json
+      |        ~~~~
+    4 | 
+    5 | const used = true
+vlib/v/checker/tests/import_mod_duplicate_err.vv:1:1: error: project must include a `main` module or be a shared library (compile with `v -shared`)
+    1 | module json
+      | ^
+    2 | 
+    3 | import json

vlib/v/checker/tests/import_mod_duplicate_err.vv

@@ -0,0 +1,7 @@
+module json
+
+import json
+
+const used = true
+
+println(json.used)

vlib/v/checker/tests/import_mod_sub_as_duplicate_err.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/import_mod_sub_as_duplicate_err.vv:3:19: error: cannot import `x.json2` as `json` into a module with the same name
+    1 | module json
+    2 | 
+    3 | import x.json2 as json
+      |                   ~~~~
+    4 | 
+    5 | println(json.Any(json.null))
+vlib/v/checker/tests/import_mod_sub_as_duplicate_err.vv:1:1: error: project must include a `main` module or be a shared library (compile with `v -shared`)
+    1 | module json
+      | ^
+    2 | 
+    3 | import x.json2 as json

vlib/v/checker/tests/import_mod_sub_as_duplicate_err.vv

@@ -0,0 +1,5 @@
+module json
+
+import x.json2 as json
+
+println(json.Any(json.null))

vlib/v/checker/tests/import_mod_sub_duplicate_as_mod.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/import_mod_sub_duplicate_as_mod.vv:1:1: error: project must include a `main` module or be a shared library (compile with `v -shared`)
+    1 | module json2
+      | ^
+    2 | 
+    3 | import x.json2 as json

vlib/v/checker/tests/import_mod_sub_duplicate_as_mod.vv

@@ -0,0 +1,7 @@
+module json2
+
+import x.json2 as json
+
+any := json.Any(json.null)
+
+println(any)

vlib/v/checker/tests/import_mod_sub_duplicate_err.out

@@ -0,0 +1,12 @@
+vlib/v/checker/tests/import_mod_sub_duplicate_err.vv:3:8: error: cannot import `x.json2` into a module with the same name
+    1 | module json2
+    2 | 
+    3 | import x.json2
+      |        ~~~~~~~
+    4 | 
+    5 | println(json2.Any(json2.null))
+vlib/v/checker/tests/import_mod_sub_duplicate_err.vv:1:1: error: project must include a `main` module or be a shared library (compile with `v -shared`)
+    1 | module json2
+      | ^
+    2 | 
+    3 | import x.json2

vlib/v/checker/tests/import_mod_sub_duplicate_err.vv

@@ -0,0 +1,5 @@
+module json2
+
+import x.json2
+
+println(json2.Any(json2.null))