From acc5c95f0df9a85ce869bd3f90496487e63a2070 Mon Sep 17 00:00:00 2001
From: Nick Treleaven <n@trelsoft.com>
Date: Mon, 24 Aug 2020 16:19:17 +0100
Subject: [PATCH] checker: error with `*expr` if not a pointer (#6211)

---
 vlib/v/checker/checker.v            | 10 ++++++++--
 vlib/v/checker/tests/prefix_err.out | 24 ++++++++++++++++++++++++
 vlib/v/checker/tests/prefix_err.vv  |  6 ++++++
 vlib/x/net/address.v                |  4 ++--
 4 files changed, 40 insertions(+), 4 deletions(-)
 create mode 100644 vlib/v/checker/tests/prefix_err.out
 create mode 100644 vlib/v/checker/tests/prefix_err.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 1357d66f63..b3fff38ea0 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -2453,8 +2453,14 @@ pub fn (mut c Checker) expr(node ast.Expr) table.Type {
 			if node.op == .amp && !right_type.is_ptr() {
 				return right_type.to_ptr()
 			}
-			if node.op == .mul && right_type.is_ptr() {
-				return right_type.deref()
+			if node.op == .mul {
+				if right_type.is_ptr() {
+					return right_type.deref()
+				}
+				if !right_type.is_pointer() {
+					s := c.table.type_to_str(right_type)
+					c.error('prefix operator `*` not defined for type `$s`', node.pos)
+				}
 			}
 			if node.op == .bit_not && !right_type.is_int() && !c.pref.translated {
 				c.error('operator ~ only defined on int types', node.pos)
diff --git a/vlib/v/checker/tests/prefix_err.out b/vlib/v/checker/tests/prefix_err.out
new file mode 100644
index 0000000000..95dfbb4dfd
--- /dev/null
+++ b/vlib/v/checker/tests/prefix_err.out
@@ -0,0 +1,24 @@
+vlib/v/checker/tests/prefix_err.v:2:5: error: prefix operator `*` not defined for type `int`
+    1 | a := 1
+    2 | _ = *a
+      |     ^
+    3 | a <- 4
+    4 |
+vlib/v/checker/tests/prefix_err.v:3:1: error: cannot push on non-channel `int`
+    1 | a := 1
+    2 | _ = *a
+    3 | a <- 4
+      | ^
+    4 |
+    5 | _ = ~true
+vlib/v/checker/tests/prefix_err.v:5:5: error: operator ~ only defined on int types
+    3 | a <- 4
+    4 |
+    5 | _ = ~true
+      |     ^
+    6 | _ = !4
+vlib/v/checker/tests/prefix_err.v:6:5: error: ! operator can only be used with bool types
+    4 |
+    5 | _ = ~true
+    6 | _ = !4
+      |     ^
diff --git a/vlib/v/checker/tests/prefix_err.vv b/vlib/v/checker/tests/prefix_err.vv
new file mode 100644
index 0000000000..6d5629f08a
--- /dev/null
+++ b/vlib/v/checker/tests/prefix_err.vv
@@ -0,0 +1,6 @@
+a := 1
+_ = *a
+a <- 4
+
+_ = ~true
+_ = !4
diff --git a/vlib/x/net/address.v b/vlib/x/net/address.v
index cf46f26c09..3ca3248559 100644
--- a/vlib/x/net/address.v
+++ b/vlib/x/net/address.v
@@ -63,7 +63,7 @@ pub fn resolve_addr(addr string, family SocketFamily, typ SocketType) ?Addr {
 
 	sport := '$port'
 
-	// This might look silly but is reccomended by MSDN
+	// This might look silly but is recommended by MSDN
 	$if windows {
 		socket_error(0-C.getaddrinfo(address.str, sport.str, &hints, &info))?
 	} $else {
@@ -71,4 +71,4 @@ pub fn resolve_addr(addr string, family SocketFamily, typ SocketType) ?Addr {
 	}
 
 	return new_addr(*info.ai_addr, address, port)
-}
\ No newline at end of file
+}