all: fix four previously ignored errors

Spotted by staticcheck. Most are pretty simple; error variables we never
used, and caused no issues.

The openapi change is a bit trickier, since openapi test files include a
"$version" top-level field. For now, explicitly ignore that field, just
like we do with "-".

Change-Id: Ia062bcfad8d25a6f0d8cc114f4d5aee475775727
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/6863
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

cue/load/config.go

@@ -395,7 +395,7 @@ func (c *Config) absDirFromImportPath(pos token.Pos, p importPath) (absDir, name
 		absDir = filepath.Join(GenPath(c.ModuleRoot), sub)
 	}
 
-	return absDir, name, nil
+	return absDir, name, err
 }
 
 // Complete updates the configuration information. After calling complete,

encoding/openapi/openapi.go

@@ -133,27 +133,29 @@ func (c *Config) compose(inst *cue.Instance, schemas *ast.StructLit) (x *ast.Str
 	var info *ast.StructLit
 
 	for i, _ := inst.Value().Fields(cue.Definitions(true)); i.Next(); {
-		if !i.IsDefinition() {
-			label := i.Label()
-			attr := i.Value().Attribute("openapi")
-			if s, _ := attr.String(0); s != "" {
-				label = s
-			}
-			switch label {
-			case "-":
-			case "info":
-				info, _ = i.Value().Syntax().(*ast.StructLit)
-				if info == nil {
-					errs = errors.Append(errs, errors.Newf(i.Value().Pos(),
-						"info must be a struct"))
-				}
-				title, _ = i.Value().Lookup("title").String()
-				version, _ = i.Value().Lookup("version").String()
-
-			default:
+		if i.IsDefinition() {
+			continue
+		}
+		label := i.Label()
+		attr := i.Value().Attribute("openapi")
+		if s, _ := attr.String(0); s != "" {
+			label = s
+		}
+		switch label {
+		case "$version":
+		case "-":
+		case "info":
+			info, _ = i.Value().Syntax().(*ast.StructLit)
+			if info == nil {
 				errs = errors.Append(errs, errors.Newf(i.Value().Pos(),
-					"openapi: unsupported top-level field %q", x))
+					"info must be a struct"))
 			}
+			title, _ = i.Value().Lookup("title").String()
+			version, _ = i.Value().Lookup("version").String()
+
+		default:
+			errs = errors.Append(errs, errors.Newf(i.Value().Pos(),
+				"openapi: unsupported top-level field %q", label))
 		}
 	}
 
@@ -210,7 +212,7 @@ func (c *Config) compose(inst *cue.Instance, schemas *ast.StructLit) (x *ast.Str
 		"info", info,
 		"paths", ast.NewStruct(),
 		"components", ast.NewStruct("schemas", schemas),
-	), nil
+	), errs
 }
 
 // Schemas extracts component/schemas from the CUE top-level types.

internal/cuetest/sim.go

@@ -65,6 +65,9 @@ func Run(t *testing.T, dir, command string, cfg *Config) {
 		cfg.Stdout = buf
 	}
 	cmd, err := cmd.New(args)
+	if err != nil {
+		t.Fatal(err)
+	}
 	if cfg.Stdout != nil {
 		cmd.SetOutput(cfg.Stdout)
 	} else {

pkg/math/math.go

@@ -386,7 +386,7 @@ func Log2(x *internal.Decimal) (*internal.Decimal, error) {
 		return &d, err
 	}
 	_, err = apdContext.Quo(&d, &d, &ln2)
-	return &d, nil
+	return &d, err
 }
 
 // Log1p returns the natural logarithm of 1 plus its argument x.