checker: revise logic for reporting import conflicts with module names (#24539)

Author: ctkjose

vlib/v/checker/checker.v

@@ -239,16 +239,21 @@ pub fn (mut c Checker) check(mut ast_file ast.File) {
 					sym.pos)
 			}
 		}
+
+		cmp_mod_name := if ast_import.mod != ast_import.alias && ast_import.alias != '_' {
+			ast_import.alias
+		} else {
+			ast_import.mod
+		}
 		for j in 0 .. i {
-			if ast_import.mod == ast_file.imports[j].mod {
-				c.error('`${ast_import.mod}` was already imported on line ${
-					ast_file.imports[j].mod_pos.line_nr + 1}', ast_import.mod_pos)
-			} else if ast_import.mod == ast_file.imports[j].alias {
-				c.error('`${ast_file.imports[j].mod}` was already imported as `${ast_import.alias}` on line ${
-					ast_file.imports[j].mod_pos.line_nr + 1}', ast_import.mod_pos)
-			} else if ast_import.alias != '_' && ast_import.alias == ast_file.imports[j].alias {
-				c.error('`${ast_file.imports[j].mod}` was already imported on line ${
-					ast_file.imports[j].alias_pos.line_nr + 1}', ast_import.alias_pos)
+			if cmp_mod_name == if ast_file.imports[j].mod != ast_file.imports[j].alias
+				&& ast_file.imports[j].alias != '_' {
+				ast_file.imports[j].alias
+			} else {
+				ast_file.imports[j].mod
+			} {
+				c.error('A module `${cmp_mod_name}` was already imported on line ${
+					ast_file.imports[j].mod_pos.line_nr + 1}`.', ast_import.mod_pos)
 			}
 		}
 	}

vlib/v/checker/tests/import_mod_as_import_alias_duplicate_err.out

@@ -1,6 +1,6 @@
-vlib/v/checker/tests/import_mod_as_import_alias_duplicate_err.vv:2:19: error: `json` was already imported on line 1
+vlib/v/checker/tests/import_mod_as_import_alias_duplicate_err.vv:2:8: error: A module `json` was already imported on line 1`.
     1 | import json
     2 | import x.json2 as json
-      |                   ~~~~
+      |        ~~~~~~~
     3 | 
     4 | numbers := {

vlib/v/checker/tests/import_mod_as_import_duplicate_err.out

@@ -1,4 +1,4 @@
-vlib/v/checker/tests/import_mod_as_import_duplicate_err.vv:2:8: error: `x.json2` was already imported as `json` on line 1
+vlib/v/checker/tests/import_mod_as_import_duplicate_err.vv:2:8: error: A module `json` was already imported on line 1`.
     1 | import x.json2 as json
     2 | import json
       |        ~~~~

vlib/v/tests/import_order_1_test.v

@@ -0,0 +1,13 @@
+// NOTE: the order of these import statements is the opposite of the one in import_order_2_test.v,
+// but *both* should compile and work:
+import x.benchmark
+import benchmark as jj
+
+fn test_runs() {
+	mut b := jj.start()
+	mut action := benchmark.setup(fn () ! {
+		return error('no')
+	})!
+	action.run()
+	b.measure('nothing')
+}

vlib/v/tests/import_order_2_test.v

@@ -0,0 +1,13 @@
+// NOTE: the order of these import statements is the opposite of the one in import_order_1_test.v,
+// but *both* should compile and work:
+import benchmark as jj
+import x.benchmark
+
+fn test_runs() {
+	mut b := jj.start()
+	mut action := benchmark.setup(fn () ! {
+		return error('no')
+	})!
+	action.run()
+	b.measure('nothing')
+}