From 5a231326d70ac92d9331274d4e9016603c46c9bb Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Thu, 11 Mar 2021 10:40:09 +0200
Subject: [PATCH] parser: improve syntax errors in module declarations

---
 vlib/v/checker/tests/module_multiple_names_err.out     |  5 -----
 vlib/v/checker/tests/module_syntax_err.out             |  5 -----
 vlib/v/parser/parser.v                                 | 10 ++++++----
 vlib/v/parser/tests/module_multiple_names_err.out      |  5 +++++
 .../tests/module_multiple_names_err.vv                 |  0
 vlib/v/parser/tests/module_syntax_err.out              |  5 +++++
 vlib/v/{checker => parser}/tests/module_syntax_err.vv  |  0
 7 files changed, 16 insertions(+), 14 deletions(-)
 delete mode 100644 vlib/v/checker/tests/module_multiple_names_err.out
 delete mode 100644 vlib/v/checker/tests/module_syntax_err.out
 create mode 100644 vlib/v/parser/tests/module_multiple_names_err.out
 rename vlib/v/{checker => parser}/tests/module_multiple_names_err.vv (100%)
 create mode 100644 vlib/v/parser/tests/module_syntax_err.out
 rename vlib/v/{checker => parser}/tests/module_syntax_err.vv (100%)

diff --git a/vlib/v/checker/tests/module_multiple_names_err.out b/vlib/v/checker/tests/module_multiple_names_err.out
deleted file mode 100644
index 5c195ef29..000000000
--- a/vlib/v/checker/tests/module_multiple_names_err.out
+++ /dev/null
@@ -1,5 +0,0 @@
-vlib/v/checker/tests/module_multiple_names_err.vv:1:13: error: `module x` can only declare one module
-    1 | module main os
-      |             ~~
-    2 | fn main() {
-    3 |     println('hello, world')
diff --git a/vlib/v/checker/tests/module_syntax_err.out b/vlib/v/checker/tests/module_syntax_err.out
deleted file mode 100644
index 4f3dcb4d1..000000000
--- a/vlib/v/checker/tests/module_syntax_err.out
+++ /dev/null
@@ -1,5 +0,0 @@
-vlib/v/checker/tests/module_syntax_err.vv:1:12: error: `module x` syntax error
-    1 | module main.os
-      |            ^
-    2 | fn main() {
-    3 |     println('hello, world')
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index 01773c9c5..5e20e5ac7 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -1835,12 +1835,14 @@ fn (mut p Parser) module_decl() ast.Module {
 		// as it creates a wrong position when extended
 		// to module_pos
 		n_pos := p.tok.position()
-		if module_pos.line_nr == n_pos.line_nr && p.tok.kind != .comment {
-			if p.tok.kind != .name {
-				p.error_with_pos('`module x` syntax error', n_pos)
+		if module_pos.line_nr == n_pos.line_nr && p.tok.kind != .comment && p.tok.kind != .eof {
+			if p.tok.kind == .name {
+				p.error_with_pos('`module $name`, you can only declare one module, unexpected `$p.tok.lit`',
+					n_pos)
 				return mod_node
 			} else {
-				p.error_with_pos('`module x` can only declare one module', n_pos)
+				p.error_with_pos('`module $name`, unexpected `$p.tok.kind` after module name',
+					n_pos)
 				return mod_node
 			}
 		}
diff --git a/vlib/v/parser/tests/module_multiple_names_err.out b/vlib/v/parser/tests/module_multiple_names_err.out
new file mode 100644
index 000000000..6ae53a873
--- /dev/null
+++ b/vlib/v/parser/tests/module_multiple_names_err.out
@@ -0,0 +1,5 @@
+vlib/v/parser/tests/module_multiple_names_err.vv:1:13: error: `module main`, you can only declare one module, unexpected `os`
+    1 | module main os
+      |             ~~
+    2 | fn main() {
+    3 |     println('hello, world')
diff --git a/vlib/v/checker/tests/module_multiple_names_err.vv b/vlib/v/parser/tests/module_multiple_names_err.vv
similarity index 100%
rename from vlib/v/checker/tests/module_multiple_names_err.vv
rename to vlib/v/parser/tests/module_multiple_names_err.vv
diff --git a/vlib/v/parser/tests/module_syntax_err.out b/vlib/v/parser/tests/module_syntax_err.out
new file mode 100644
index 000000000..38a1905e1
--- /dev/null
+++ b/vlib/v/parser/tests/module_syntax_err.out
@@ -0,0 +1,5 @@
+vlib/v/parser/tests/module_syntax_err.vv:1:12: error: `module main`, unexpected `.` after module name
+    1 | module main.os
+      |            ^
+    2 | fn main() {
+    3 |     println('hello, world')
diff --git a/vlib/v/checker/tests/module_syntax_err.vv b/vlib/v/parser/tests/module_syntax_err.vv
similarity index 100%
rename from vlib/v/checker/tests/module_syntax_err.vv
rename to vlib/v/parser/tests/module_syntax_err.vv
-- 
2.39.5