From 9d8bda9eafd4ce3fbad8d750a213c06d41e7d396 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Tue, 20 Apr 2021 11:49:06 +0300
Subject: [PATCH] v.ast, v.checker: fix absent 'missing return' warning, when a
 function ended with a t.panic() call

---
 vlib/v/ast/table.v                                | 11 +++++++++++
 vlib/v/checker/checker.v                          |  6 +++---
 .../tests/function_missing_return_type.out        |  7 +++++++
 .../checker/tests/function_missing_return_type.vv | 15 +++++++++++++++
 4 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/vlib/v/ast/table.v b/vlib/v/ast/table.v
index 6cafd8ab94..d20a6105b7 100644
--- a/vlib/v/ast/table.v
+++ b/vlib/v/ast/table.v
@@ -431,6 +431,15 @@ pub fn (t &Table) find_type(name string) ?TypeSymbol {
 	return none
 }
 
+pub const invalid_type_symbol = &TypeSymbol{
+	parent_idx: -1
+	language: .v
+	mod: 'builtin'
+	kind: .placeholder
+	name: 'InvalidType'
+	cname: 'InvalidType'
+}
+
 [inline]
 pub fn (t &Table) get_type_symbol(typ Type) &TypeSymbol {
 	// println('get_type_symbol $typ')
@@ -441,6 +450,7 @@ pub fn (t &Table) get_type_symbol(typ Type) &TypeSymbol {
 	// this should never happen
 	t.panic('get_type_symbol: invalid type (typ=$typ idx=$idx). Compiler bug. This should never happen. Please report the bug using `v bug file.v`.
 ')
+	return ast.invalid_type_symbol
 }
 
 // get_final_type_symbol follows aliases until it gets to a "real" Type
@@ -457,6 +467,7 @@ pub fn (t &Table) get_final_type_symbol(typ Type) &TypeSymbol {
 	}
 	// this should never happen
 	t.panic('get_final_type_symbol: invalid type (typ=$typ idx=$idx). Compiler bug. This should never happen. Please report the bug using `v bug file.v`.')
+	return ast.invalid_type_symbol
 }
 
 [inline]
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index a064919618..291f213335 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -2511,7 +2511,7 @@ pub fn (mut c Checker) check_or_expr(or_expr ast.OrExpr, ret_type ast.Type, expr
 
 fn is_expr_panic_or_exit(expr ast.Expr) bool {
 	match expr {
-		ast.CallExpr { return expr.name in ['panic', 'exit'] }
+		ast.CallExpr { return !expr.is_method && expr.name in ['panic', 'exit'] }
 		else { return false }
 	}
 }
@@ -6584,7 +6584,7 @@ fn (mut c Checker) fn_decl(mut node ast.FnDecl) {
 	c.stmts(node.stmts)
 	node.has_return = c.returns || has_top_return(node.stmts)
 	if node.language == .v && !node.no_body && node.return_type != ast.void_type && !node.has_return
-		&& node.name !in ['panic', 'exit'] {
+		&& (node.is_method || node.name !in ['panic', 'exit']) {
 		if c.inside_anon_fn {
 			c.error('missing return at the end of an anonymous function', node.pos)
 		} else {
@@ -6605,7 +6605,7 @@ fn has_top_return(stmts []ast.Stmt) bool {
 			}
 		} else if stmt is ast.ExprStmt {
 			if stmt.expr is ast.CallExpr {
-				if stmt.expr.name in ['panic', 'exit'] {
+				if !stmt.expr.is_method && stmt.expr.name in ['panic', 'exit'] {
 					return true
 				}
 			}
diff --git a/vlib/v/checker/tests/function_missing_return_type.out b/vlib/v/checker/tests/function_missing_return_type.out
index 70c8c0ded1..73292af5ea 100644
--- a/vlib/v/checker/tests/function_missing_return_type.out
+++ b/vlib/v/checker/tests/function_missing_return_type.out
@@ -3,3 +3,10 @@ vlib/v/checker/tests/function_missing_return_type.vv:1:1: error: missing return
       | ~~~~~~~~~~
     2 | }
     3 |
+vlib/v/checker/tests/function_missing_return_type.vv:12:1: error: missing return at end of function `abc`
+   10 | }
+   11 | 
+   12 | fn (s Abc) abc() &int {
+      | ~~~~~~~~~~~~~~~~~~~~~
+   13 |     if true {
+   14 |         return &s.x
diff --git a/vlib/v/checker/tests/function_missing_return_type.vv b/vlib/v/checker/tests/function_missing_return_type.vv
index adaf7b5a5d..74d8cc1e8d 100644
--- a/vlib/v/checker/tests/function_missing_return_type.vv
+++ b/vlib/v/checker/tests/function_missing_return_type.vv
@@ -1,6 +1,21 @@
 fn h() int {
 }
 
+struct Abc {
+	x int
+}
+
+fn (s Abc) panic(message string) {
+	println('called ${@METHOD} with message: $message')
+}
+
+fn (s Abc) abc() &int {
+	if true {
+		return &s.x
+	}
+	s.panic(@FN)
+}
+
 fn main() {
 	d := h()
 	println('$d')