From 1b09954622a09eb2072883738b89331e0bf77424 Mon Sep 17 00:00:00 2001
From: zakuro <z@kuro.red>
Date: Fri, 22 Jan 2021 16:38:37 +0900
Subject: [PATCH] parser: improve the position of mut receiver warning / error
 (#8240)

---
 vlib/v/checker/tests/mut_receiver.out              | 14 ++++++++++++++
 .../{mut_receiver_warning.vv => mut_receiver.vv}   |  3 +++
 vlib/v/checker/tests/mut_receiver_warning.out      |  7 -------
 vlib/v/parser/fn.v                                 |  6 ++++--
 4 files changed, 21 insertions(+), 9 deletions(-)
 create mode 100644 vlib/v/checker/tests/mut_receiver.out
 rename vlib/v/checker/tests/{mut_receiver_warning.vv => mut_receiver.vv} (71%)
 delete mode 100644 vlib/v/checker/tests/mut_receiver_warning.out

diff --git a/vlib/v/checker/tests/mut_receiver.out b/vlib/v/checker/tests/mut_receiver.out
new file mode 100644
index 0000000000..fb160a4f2c
--- /dev/null
+++ b/vlib/v/checker/tests/mut_receiver.out
@@ -0,0 +1,14 @@
+vlib/v/checker/tests/mut_receiver.vv:5:4: warning: use `(mut f Foo)` instead of `(f mut Foo)`
+    3 |     name string
+    4 | }
+    5 | fn (f mut Foo) info() {
+      |    ~~~~~~~~~~~
+    6 |     f.name = 'foo'
+    7 | }
+vlib/v/checker/tests/mut_receiver.vv:8:4: error: use `(mut f Foo)` or `(f &Foo)` instead of `(mut f &Foo)`
+    6 |     f.name = 'foo'
+    7 | }
+    8 | fn (mut f &Foo) info2() {
+      |    ~~~~~~~~~~~~
+    9 |     f.name = 'foo'
+   10 | }
diff --git a/vlib/v/checker/tests/mut_receiver_warning.vv b/vlib/v/checker/tests/mut_receiver.vv
similarity index 71%
rename from vlib/v/checker/tests/mut_receiver_warning.vv
rename to vlib/v/checker/tests/mut_receiver.vv
index e01bb499e3..fae05df9ba 100644
--- a/vlib/v/checker/tests/mut_receiver_warning.vv
+++ b/vlib/v/checker/tests/mut_receiver.vv
@@ -5,6 +5,9 @@ mut:
 fn (f mut Foo) info() {
 	f.name = 'foo'
 }
+fn (mut f &Foo) info2() {
+	f.name = 'foo'
+}
 fn main() {
 	println('hello, world')
 }
diff --git a/vlib/v/checker/tests/mut_receiver_warning.out b/vlib/v/checker/tests/mut_receiver_warning.out
deleted file mode 100644
index 90aaf0eb80..0000000000
--- a/vlib/v/checker/tests/mut_receiver_warning.out
+++ /dev/null
@@ -1,7 +0,0 @@
-vlib/v/checker/tests/mut_receiver_warning.vv:5:7: warning: use `(mut f Foo)` instead of `(f mut Foo)`
-    3 |     name string
-    4 | }
-    5 | fn (f mut Foo) info() {
-      |       ~~~
-    6 |     f.name = 'foo'
-    7 | }
\ No newline at end of file
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index 4e6407dfdc..17a14e1b75 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -195,6 +195,7 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 	mut rec_mut := false
 	mut params := []table.Param{}
 	if p.tok.kind == .lpar {
+		lpar_pos := p.tok.position()
 		p.next() // (
 		is_method = true
 		is_shared := p.tok.kind == .key_shared
@@ -208,7 +209,7 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 		if !rec_mut {
 			rec_mut = p.tok.kind == .key_mut
 			if rec_mut {
-				p.warn_with_pos('use `(mut f Foo)` instead of `(f mut Foo)`', p.tok.position())
+				p.warn_with_pos('use `(mut f Foo)` instead of `(f mut Foo)`', lpar_pos.extend(p.peek_tok2.position()))
 			}
 		}
 		receiver_pos = rec_start_pos.extend(p.tok.position())
@@ -231,7 +232,8 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 		}
 		rec_type_pos = rec_type_pos.extend(p.prev_tok.position())
 		if is_amp && rec_mut {
-			p.error('use `(mut f Foo)` or `(f &Foo)` instead of `(mut f &Foo)`')
+			p.error_with_pos('use `(mut f Foo)` or `(f &Foo)` instead of `(mut f &Foo)`',
+				lpar_pos.extend(p.tok.position()))
 			return ast.FnDecl{
 				scope: 0
 			}