parser: check that functions return in all if/else branches

compiler/fn.v

@@ -927,6 +927,7 @@ fn (p mut Parser) fn_call_args(f mut Fn) *Fn {
 	}
 	p.check(.rpar)
 	// p.gen(')')
+	return f // TODO is return f right?
 }
 
 // "fn (int, string) int"

compiler/parser.v

@@ -2928,6 +2928,8 @@ fn (p mut Parser) if_st(is_expr bool, elif_depth int) string {
 	else {
 		typ = p.statements()
 	}
+	if_returns := p.returns
+	p.returns = false
 	// println('IF TYp=$typ')
 	if p.tok == .key_else {
 		p.fgenln('') 
@@ -2959,6 +2961,8 @@ fn (p mut Parser) if_st(is_expr bool, elif_depth int) string {
 		}
 		return typ
 	}
+	else_returns := p.returns
+	p.returns = if_returns && else_returns
 	p.inside_if_expr = false
 	if p.fileis('test_test') {
 		println('if ret typ="$typ" line=$p.scanner.line_nr')

compiler/table.v

@@ -739,6 +739,8 @@ fn (t mut Table) fn_gen_types(fn_name string) []string {
 			return f.types
 		} 
 	} 
+	panic('function $fn_name not found') // TODO panic or return []?
+	return []string // TODO remove return
 } 
 
 // `foo<Bar>()`

compiler/vfmt.v

@@ -45,6 +45,7 @@ fn (p mut Parser) peek() Token {
 			return tok
 		}
 	}
+	return .eof // TODO can never get here - v doesn't know that
 }
 
 fn (p mut Parser) fmt_inc() {

examples/news_fetcher.v

@@ -36,10 +36,12 @@ fn (f mut Fetcher) fetch() {
 		resp := http.get('https://hacker-news.firebaseio.com/v0/item/${id}.json') or {
 			println('failed to fetch data from /v0/item/${id}.json')
 			exit(1)
+			return // TODO remove return
 		}
 		story := json.decode(Story, resp.text) or {
 			println('failed to decode a story')
 			exit(1)
+			return // TODO remove return
 		}
 		f.wg.done()
 		println('#$cursor) $story.title | $story.url')

make_tests.bat

@@ -23,6 +23,7 @@ for /r . %%x in (*_test.v) do (
   v -os msvc -o test.exe -debug %%x
   if !ERRORLEVEL! NEQ 0 goto :fail
 )
+
 for /r . %%x in (*_test.v) do (
   v.msvc.exe -os msvc -o test.exe -debug %%x
   if !ERRORLEVEL! NEQ 0 goto :fail

vlib/builtin/string.v

@@ -462,6 +462,7 @@ pub fn (s string) count(substr string) int {
 		i += substr.len
 		n++
 	}
+	return 0 // TODO can never get here - v doesn't know that
 }
 
 pub fn (s string) contains(p string) bool {

vlib/math/complex/complex.v

@@ -489,8 +489,7 @@ pub fn (c Complex) acsch() Complex {
 		)
 		.divide(c)
 		.ln()
-	}
+	} else {
-	if(c.re > 0) {
 		return one.add(
 			one.add(
 				c.pow(2) 

vlib/math/fractions/fraction.v

@@ -19,6 +19,7 @@ pub fn fraction(n i64, d i64) Fraction{
 	} 
 	else {
 		panic('Denominator cannot be zero')
+		return Fraction{} // TODO remove return
 	}
 }