go/types, types2: use "assignment mismatch: x variables but y values" error message

This matches current compiler behavior.

For #55326.

Change-Id: I7197cf4ce21e614291a1a2e1048dd78d0a232b64
Reviewed-on: https://go-review.googlesource.com/c/go/+/436175
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Griesemer <gri@google.com>

src/cmd/compile/internal/types2/assignments.go

@@ -353,11 +353,7 @@ func (check *Checker) initVars(lhs []*Var, orig_rhs []syntax.Expr, returnStmt sy
 			check.report(&err)
 			return
 		}
-		if check.conf.CompilerErrorMessages {
-			check.assignError(orig_rhs, len(lhs), len(rhs))
-		} else {
-			check.errorf(rhs[0], _WrongAssignCount, "cannot initialize %d variables with %d values", len(lhs), len(rhs))
-		}
+		check.assignError(orig_rhs, len(lhs), len(rhs))
 		return
 	}
 
@@ -401,11 +397,7 @@ func (check *Checker) assignVars(lhs, orig_rhs []syntax.Expr) {
 				return
 			}
 		}
-		if check.conf.CompilerErrorMessages {
-			check.assignError(orig_rhs, len(lhs), len(rhs))
-		} else {
-			check.errorf(rhs[0], _WrongAssignCount, "cannot assign %d values to %d variables", len(rhs), len(lhs))
-		}
+		check.assignError(orig_rhs, len(lhs), len(rhs))
 		return
 	}
 

src/go/types/assignments.go

@@ -346,11 +346,7 @@ func (check *Checker) initVars(lhs []*Var, origRHS []ast.Expr, returnStmt ast.St
 			check.report(err)
 			return
 		}
-		if compilerErrorMessages {
-			check.assignError(origRHS, len(lhs), len(rhs))
-		} else {
-			check.errorf(rhs[0], _WrongAssignCount, "cannot initialize %d variables with %d values", len(lhs), len(rhs))
-		}
+		check.assignError(origRHS, len(lhs), len(rhs))
 		return
 	}
 
@@ -384,11 +380,7 @@ func (check *Checker) assignVars(lhs, origRHS []ast.Expr) {
 				return
 			}
 		}
-		if compilerErrorMessages {
-			check.assignError(origRHS, len(lhs), len(rhs))
-		} else {
-			check.errorf(rhs[0], _WrongAssignCount, "cannot assign %d values to %d variables", len(rhs), len(lhs))
-		}
+		check.assignError(origRHS, len(lhs), len(rhs))
 		return
 	}
 

src/internal/types/testdata/check/decls1.go

@@ -78,7 +78,7 @@ var (
 	u2 = iface.([]int)
 	u3 = iface.(a /* ERROR "not a type" */ )
 	u4, ok = iface.(int)
-	u5, ok2, ok3 = iface /* ERROR "cannot initialize" */ .(int)
+	u5, ok2, ok3 = iface /* ERROR "assignment mismatch" */ .(int)
 )
 
 // Constant expression initializations

src/internal/types/testdata/check/issues0.go

@@ -105,8 +105,8 @@ func issue10979() {
 // issue11347
 // These should not crash.
 var a1, b1 /* ERROR cycle */ , c1 /* ERROR cycle */ b1 = 0 > 0<<""[""[c1]]>c1
-var a2, b2 /* ERROR cycle */ = 0 /* ERROR cannot initialize */ /* ERROR cannot initialize */ > 0<<""[b2]
-var a3, b3 /* ERROR cycle */ = int /* ERROR cannot initialize */ /* ERROR cannot initialize */ (1<<""[b3])
+var a2, b2 /* ERROR cycle */ = 0 /* ERROR assignment mismatch */ /* ERROR assignment mismatch */ > 0<<""[b2]
+var a3, b3 /* ERROR cycle */ = int /* ERROR assignment mismatch */ /* ERROR assignment mismatch */ (1<<""[b3])
 
 // issue10260
 // Check that error messages explain reason for interface assignment failures.

src/internal/types/testdata/check/stmt0.go

@@ -15,19 +15,19 @@ func assignments0() (int, int) {
 	f3 := func() (int, int, int) { return 1, 2, 3 }
 
 	a, b, c = 1, 2, 3
-	a, b, c = 1 /* ERROR "cannot assign [1-9]+ values to [1-9]+ variables" */ , 2
-	a, b, c = 1 /* ERROR "cannot assign [1-9]+ values to [1-9]+ variables" */ , 2, 3, 4
+	a, b, c = 1 /* ERROR "assignment mismatch: 3 variables but 2 values" */ , 2
+	a, b, c = 1 /* ERROR "assignment mismatch: 3 variables but 4 values" */ , 2, 3, 4
 	_, _, _ = a, b, c
 
 	a = f0 /* ERROR "used as value" */ ()
 	a = f1()
-	a = f2 /* ERROR "cannot assign [1-9]+ values to [1-9]+ variables" */ ()
+	a = f2 /* ERROR "assignment mismatch: 1 variable but f2 returns 2 values" */ ()
 	a, b = f2()
-	a, b, c = f2 /* ERROR "cannot assign [1-9]+ values to [1-9]+ variables" */ ()
+	a, b, c = f2 /* ERROR "assignment mismatch: 3 variables but f2 returns 2 values" */ ()
 	a, b, c = f3()
-	a, b = f3 /* ERROR "cannot assign [1-9]+ values to [1-9]+ variables" */ ()
+	a, b = f3 /* ERROR "assignment mismatch: 2 variables but f3 returns 3 values" */ ()
 
-	a, b, c = <- /* ERROR "cannot assign [1-9]+ values to [1-9]+ variables" */ ch
+	a, b, c = <- /* ERROR "assignment mismatch: 3 variables but 1 value" */ ch
 
 	return /* ERROR "not enough return values\n\thave \(\)\n\twant \(int, int\)" */
 	return 1 /* ERROR "not enough return values\n\thave \(number\)\n\twant \(int, int\)" */
@@ -43,7 +43,7 @@ func assignments1() {
 	c = s /* ERROR "cannot use .* in assignment" */
 	s = b /* ERROR "cannot use .* in assignment" */
 
-	v0, v1, v2 := 1 /* ERROR "cannot initialize" */ , 2, 3, 4
+	v0, v1, v2 := 1 /* ERROR "assignment mismatch" */ , 2, 3, 4
 	_, _, _ = v0, v1, v2
 
 	b = true
@@ -108,7 +108,7 @@ func assignments2() {
 	s, b = m["foo"]
 	_, d = m["bar"]
 	m["foo"] = nil
-	m["foo"] = nil /* ERROR cannot assign [1-9]+ values to [1-9]+ variables */ , false
+	m["foo"] = nil /* ERROR assignment mismatch: 1 variable but 2 values */ , false
 	_ = append(m["foo"])
 	_ = append(m["foo"], true)
 
@@ -116,12 +116,12 @@ func assignments2() {
 	_, b = <-c
 	_, d = <-c
 	<- /* ERROR cannot assign */ c = 0
-	<-c = 0 /* ERROR cannot assign [1-9]+ values to [1-9]+ variables */ , false
+	<-c = 0 /* ERROR assignment mismatch: 1 variable but 2 values */ , false
 
 	var x interface{}
 	_, b = x.(int)
 	x /* ERROR cannot assign */ .(int) = 0
-	x.(int) = 0 /* ERROR cannot assign [1-9]+ values to [1-9]+ variables */ , false
+	x.(int) = 0 /* ERROR assignment mismatch: 1 variable but 2 values */ , false
 
 	assignments2 /* ERROR used as value */ () = nil
 	int /* ERROR not an expression */ = 0

src/internal/types/testdata/check/vardecl.go

@@ -25,39 +25,39 @@ var _ = f /* ERROR "used as value" */ ()
 // Identifier and expression arity must match.
 var _, _ = 1, 2
 var _ = 1, 2 /* ERROR "extra init expr 2" */
-var _, _ = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
+var _, _ = 1 /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */
 var _, _, _ /* ERROR "missing init expr for _" */ = 1, 2
 
 var _ = g /* ERROR "multiple-value g" */ ()
 var _, _ = g()
-var _, _, _ = g /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ()
+var _, _, _ = g /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */ ()
 
 var _ = m["foo"]
 var _, _ = m["foo"]
-var _, _, _ = m  /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ["foo"]
+var _, _, _ = m  /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */ ["foo"]
 
 var _, _ int = 1, 2
 var _ int = 1, 2 /* ERROR "extra init expr 2" */
-var _, _ int = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
+var _, _ int = 1 /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */
 var _, _, _ /* ERROR "missing init expr for _" */ int = 1, 2
 
 var (
 	_, _ = 1, 2
 	_ = 1, 2 /* ERROR "extra init expr 2" */
-	_, _ = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
+	_, _ = 1 /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */
 	_, _, _ /* ERROR "missing init expr for _" */ = 1, 2
 
 	_ = g /* ERROR "multiple-value g" */ ()
 	_, _ = g()
-	_, _, _ = g /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ()
+	_, _, _ = g /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */ ()
 
 	_ = m["foo"]
 	_, _ = m["foo"]
-	_, _, _ = m /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */ ["foo"]
+	_, _, _ = m /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */ ["foo"]
 
 	_, _ int = 1, 2
 	_ int = 1, 2 /* ERROR "extra init expr 2" */
-	_, _ int = 1 /* ERROR "cannot initialize [0-9]+ variables with [0-9]+ values" */
+	_, _ int = 1 /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */
 	_, _, _ /* ERROR "missing init expr for _" */ int = 1, 2
 )
 
@@ -171,7 +171,7 @@ func _() {
 func _() {
 	var a, b, c int
 	var x, y int
-	x, y = a /* ERROR cannot assign [0-9]+ values to [0-9]+ variables */ , b, c
+	x, y = a /* ERROR "assignment mismatch: [1-9]+ variables but.*[1-9]+ value(s)?" */ , b, c
 	_ = x
 	_ = y
 }