cmd/compile: improve not enough / too many arguments errors

Use "have" and "want" and multiple lines like other similar error
messages. Also, fix handling of ... and multi-value function calls.

Fixes #17650.

Change-Id: I4850e79c080eac8df3b92a4accf9e470dff63c9a
Reviewed-on: https://go-review.googlesource.com/32261Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/compile/internal/gc/typecheck.go

@@ -2692,12 +2692,12 @@ notenough:
 			// Method expressions have the form T.M, and the compiler has
 			// rewritten those to ONAME nodes but left T in Left.
 			if call.Op == ONAME && call.Left != nil && call.Left.Op == OTYPE {
-				yyerror("not enough arguments in call to method expression %v, got %s want %v", call, nl.retsigerr(), tstruct)
+				yyerror("not enough arguments in call to method expression %v\n\thave %s\n\twant %v", call, nl.retsigerr(isddd), tstruct)
 			} else {
-				yyerror("not enough arguments in call to %v, got %s want %v", call, nl.retsigerr(), tstruct)
+				yyerror("not enough arguments in call to %v\n\thave %s\n\twant %v", call, nl.retsigerr(isddd), tstruct)
 			}
 		} else {
-			yyerror("not enough arguments to %v, got %s want %v", op, nl.retsigerr(), tstruct)
+			yyerror("not enough arguments to %v\n\thave %s\n\twant %v", op, nl.retsigerr(isddd), tstruct)
 		}
 		if n != nil {
 			n.Diag = 1
@@ -2708,9 +2708,9 @@ notenough:
 
 toomany:
 	if call != nil {
-		yyerror("too many arguments in call to %v, got %s want %v", call, nl.retsigerr(), tstruct)
+		yyerror("too many arguments in call to %v\n\thave %s\n\twant %v", call, nl.retsigerr(isddd), tstruct)
 	} else {
-		yyerror("too many arguments to %v, got %s want %v", op, nl.retsigerr(), tstruct)
+		yyerror("too many arguments to %v\n\thave %s\n\twant %v", op, nl.retsigerr(isddd), tstruct)
 	}
 	goto out
 }
@@ -2738,17 +2738,27 @@ func (t *Type) sigrepr() string {
 
 // retsigerr returns the signature of the types
 // at the respective return call site of a function.
-func (nl Nodes) retsigerr() string {
+func (nl Nodes) retsigerr(isddd bool) string {
 	if nl.Len() < 1 {
 		return "()"
 	}
 
 	var typeStrings []string
-	for _, n := range nl.Slice() {
-		typeStrings = append(typeStrings, n.Type.sigrepr())
+	if nl.Len() == 1 && nl.First().Type != nil && nl.First().Type.IsFuncArgStruct() {
+		for _, f := range nl.First().Type.Fields().Slice() {
+			typeStrings = append(typeStrings, f.Type.sigrepr())
+		}
+	} else {
+		for _, n := range nl.Slice() {
+			typeStrings = append(typeStrings, n.Type.sigrepr())
+		}
 	}
 
-	return fmt.Sprintf("(%s)", strings.Join(typeStrings, ", "))
+	ddd := ""
+	if isddd {
+		ddd = "..."
+	}
+	return fmt.Sprintf("(%s%s)", strings.Join(typeStrings, ", "), ddd)
 }
 
 // type check composite

test/ddd1.go

@@ -27,9 +27,9 @@ func tuple() (int, int, int) { return 1, 2, 3 }
 
 var (
 	_ = sum(tuple())
-	_ = sum(tuple()...) // ERROR "multiple-value|[.][.][.]"
+	_ = sum(tuple()...) // ERROR "multiple-value"
 	_ = sum3(tuple())
-	_ = sum3(tuple()...) // ERROR "multiple-value|[.][.][.]" "not enough"
+	_ = sum3(tuple()...) // ERROR "multiple-value" "not enough"
 )
 
 type T []T
@@ -59,4 +59,3 @@ func bad(args ...int) {
 	_ = [...]byte("foo") // ERROR "[.][.][.]"
 	_ = [...][...]int{{1,2,3},{4,5,6}}	// ERROR "[.][.][.]"
 }
-

test/fixedbugs/issue4215.go

@@ -7,28 +7,28 @@
 package main
 
 func foo() (int, int) {
-	return 2.3 // ERROR "not enough arguments to return, got \(number\) want \(int, int\)"
+	return 2.3 // ERROR "not enough arguments to return\n\thave \(number\)\n\twant \(int, int\)"
 }
 
 func foo2() {
-	return int(2), 2 // ERROR "too many arguments to return, got \(int, number\) want \(\)"
+	return int(2), 2 // ERROR "too many arguments to return\n\thave \(int, number\)\n\twant \(\)"
 }
 
 func foo3(v int) (a, b, c, d int) {
 	if v >= 0 {
-		return 1 // ERROR "not enough arguments to return, got \(number\) want \(int, int, int, int\)"
+		return 1 // ERROR "not enough arguments to return\n\thave \(number\)\n\twant \(int, int, int, int\)"
 	}
-	return 2, 3 // ERROR "not enough arguments to return, got \(number, number\) want \(int, int, int, int\)"
+	return 2, 3 // ERROR "not enough arguments to return\n\thave \(number, number\)\n\twant \(int, int, int, int\)"
 }
 
 func foo4(name string) (string, int) {
 	switch name {
 	case "cow":
-		return "moo" // ERROR "not enough arguments to return, got \(string\) want \(string, int\)"
+		return "moo" // ERROR "not enough arguments to return\n\thave \(string\)\n\twant \(string, int\)"
 	case "dog":
-		return "dog", 10, true // ERROR "too many arguments to return, got \(string, number, bool\) want \(string, int\)"
+		return "dog", 10, true // ERROR "too many arguments to return\n\thave \(string, number, bool\)\n\twant \(string, int\)"
 	case "fish":
-		return "" // ERROR "not enough arguments to return, got \(string\) want \(string, int\)"
+		return "" // ERROR "not enough arguments to return\n\thave \(string\)\n\twant \(string, int\)"
 	default:
 		return "lizard", 10
 	}
@@ -40,14 +40,14 @@ type U float64
 
 func foo5() (S, T, U) {
 	if false {
-		return "" // ERROR "not enough arguments to return, got \(string\) want \(S, T, U\)"
+		return "" // ERROR "not enough arguments to return\n\thave \(string\)\n\twant \(S, T, U\)"
 	} else {
 		ptr := new(T)
-		return ptr // ERROR "not enough arguments to return, got \(\*T\) want \(S, T, U\)"
+		return ptr // ERROR "not enough arguments to return\n\thave \(\*T\)\n\twant \(S, T, U\)"
 	}
-	return new(S), 12.34, 1 + 0i, 'r', true // ERROR "too many arguments to return, got \(\*S, number, number, number, bool\) want \(S, T, U\)"
+	return new(S), 12.34, 1 + 0i, 'r', true // ERROR "too many arguments to return\n\thave \(\*S, number, number, number, bool\)\n\twant \(S, T, U\)"
 }
 
 func foo6() (T, string) {
-	return "T", true, true // ERROR "too many arguments to return, got \(string, bool, bool\) want \(T, string\)"
+	return "T", true, true // ERROR "too many arguments to return\n\thave \(string, bool, bool\)\n\twant \(T, string\)"
 }

test/fixedbugs/issue6750.go

@@ -18,5 +18,5 @@ func printmany(nums ...int) {
 func main() {
 	printmany(1, 2, 3)
 	printmany([]int{1, 2, 3}...)
-	printmany(1, "abc", []int{2, 3}...) // ERROR "too many arguments in call to printmany, got \(number, string, \[\]int\) want \(...int\)"
+	printmany(1, "abc", []int{2, 3}...) // ERROR "too many arguments in call to printmany\n\thave \(number, string, \[\]int\.\.\.\)\n\twant \(...int\)"
 }