diff --git a/builtin/providers/aws/tags_test.go b/builtin/providers/aws/tags_test.go
index eb30f346e..6e89492ca 100644
--- a/builtin/providers/aws/tags_test.go
+++ b/builtin/providers/aws/tags_test.go
@@ -53,10 +53,10 @@ func TestDiffTags(t *testing.T) {
 		cm := tagsToMap(c)
 		rm := tagsToMap(r)
 		if !reflect.DeepEqual(cm, tc.Create) {
-			t.Fatalf("%i: bad create: %#v", i, cm)
+			t.Fatalf("%d: bad create: %#v", i, cm)
 		}
 		if !reflect.DeepEqual(rm, tc.Remove) {
-			t.Fatalf("%i: bad remove: %#v", i, rm)
+			t.Fatalf("%d: bad remove: %#v", i, rm)
 		}
 	}
 }
diff --git a/config/config_test.go b/config/config_test.go
index 1574ba83a..7b7348fd9 100644
--- a/config/config_test.go
+++ b/config/config_test.go
@@ -98,7 +98,7 @@ func TestConfigValidate_countUserVar(t *testing.T) {
 func TestConfigValidate_countVar(t *testing.T) {
 	c := testConfig(t, "validate-count-var")
 	if err := c.Validate(); err != nil {
-		t.Fatal("err: %s", err)
+		t.Fatalf("err: %s", err)
 	}
 }
 
@@ -154,7 +154,7 @@ func TestConfigValidate_outputBadField(t *testing.T) {
 func TestConfigValidate_pathVar(t *testing.T) {
 	c := testConfig(t, "validate-path-var")
 	if err := c.Validate(); err != nil {
-		t.Fatal("err: %s", err)
+		t.Fatalf("err: %s", err)
 	}
 }
 
diff --git a/config/module/get_file_test.go b/config/module/get_file_test.go
index 7cc69bccb..4c9f6126a 100644
--- a/config/module/get_file_test.go
+++ b/config/module/get_file_test.go
@@ -88,7 +88,7 @@ func TestFileGetter_dirSymlink(t *testing.T) {
 
 	// Make a symlink
 	if err := os.Symlink(dst2, dst); err != nil {
-		t.Fatalf("err: %s")
+		t.Fatalf("err: %s", err)
 	}
 
 	// With a dir that exists that isn't a symlink
diff --git a/helper/schema/schema.go b/helper/schema/schema.go
index 7cd0fe711..be5a56aa3 100644
--- a/helper/schema/schema.go
+++ b/helper/schema/schema.go
@@ -338,7 +338,7 @@ func (m schemaMap) Input(
 		case TypeString:
 			value, err = m.inputString(input, k, v)
 		default:
-			panic(fmt.Sprintf("Unknown type for input: %s", v.Type))
+			panic(fmt.Sprintf("Unknown type for input: %#v", v.Type))
 		}
 
 		if err != nil {
@@ -653,7 +653,7 @@ func (m schemaMap) diffString(
 			var err error
 			n, err = schema.DefaultFunc()
 			if err != nil {
-				return fmt.Errorf("%s, error loading default: %s", err)
+				return fmt.Errorf("%s, error loading default: %s", k, err)
 			}
 		}
 	}
@@ -909,7 +909,7 @@ func (m schemaMap) validatePrimitive(
 			return nil, []error{err}
 		}
 	default:
-		panic(fmt.Sprintf("Unknown validation type: %s", schema.Type))
+		panic(fmt.Sprintf("Unknown validation type: %#v", schema.Type))
 	}
 
 	return nil, nil
diff --git a/terraform/context.go b/terraform/context.go
index e2d8bbd33..81735063f 100644
--- a/terraform/context.go
+++ b/terraform/context.go
@@ -175,7 +175,7 @@ func (c *Context) Input(mode InputMode) error {
 			case config.VariableTypeString:
 				// Good!
 			default:
-				panic(fmt.Sprintf("Unknown variable type: %s", v.Type()))
+				panic(fmt.Sprintf("Unknown variable type: %#v", v.Type()))
 			}
 
 			var defaultString string
@@ -483,7 +483,7 @@ func (c *walkContext) Walk() error {
 	case walkValidate:
 		walkFn = c.validateWalkFn()
 	default:
-		panic(fmt.Sprintf("unknown operation: %s", c.Operation))
+		panic(fmt.Sprintf("unknown operation: %#v", c.Operation))
 	}
 
 	if err := g.Walk(walkFn); err != nil {
diff --git a/terraform/diff_test.go b/terraform/diff_test.go
index dcee2b335..47e78c5e8 100644
--- a/terraform/diff_test.go
+++ b/terraform/diff_test.go
@@ -97,7 +97,7 @@ func TestModuleDiff_ChangeType(t *testing.T) {
 	for i, tc := range cases {
 		actual := tc.Diff.ChangeType()
 		if actual != tc.Result {
-			t.Fatalf("%d: %s", i, actual)
+			t.Fatalf("%d: %#v", i, actual)
 		}
 	}
 }
@@ -232,7 +232,7 @@ func TestInstanceDiff_ChangeType(t *testing.T) {
 	for i, tc := range cases {
 		actual := tc.Diff.ChangeType()
 		if actual != tc.Result {
-			t.Fatalf("%d: %s", i, actual)
+			t.Fatalf("%d: %#v", i, actual)
 		}
 	}
 }