hclwrite: Fix panic for dotted full splat (foo.*)

The following expression caused a panic in hclwrite:

  a = foo.*

This was due to the unusual dotted form of a full splat (where the splat
operator is at the end of the expression) being generated with an
invalid source range. In the full splat case, the end of the range was
uninitialized, which caused the token slice to be empty, and thus the
panic.

This commit fixes the bug, adds test coverage, and includes some bonus
tests for other splat expression cases.

hclsyntax/parser.go

@@ -670,6 +670,7 @@ Traversal:
 				trav := make(hcl.Traversal, 0, 1)
 				var firstRange, lastRange hcl.Range
 				firstRange = p.NextRange()
+				lastRange = marker.Range
 				for p.Peek().Type == TokenDot {
 					dot := p.Read()
 

hclwrite/parser_test.go

@@ -618,6 +618,222 @@ func TestParse(t *testing.T) {
 				},
 			},
 		},
+		{
+			"a = foo.*\n",
+			TestTreeNode{
+				Type: "Body",
+				Children: []TestTreeNode{
+					{
+						Type: "Attribute",
+						Children: []TestTreeNode{
+							{
+								Type: "comments",
+							},
+							{
+								Type: "identifier",
+								Val:  "a",
+							},
+							{
+								Type: "Tokens",
+								Val:  " =",
+							},
+							{
+								Type: "Expression",
+								Children: []TestTreeNode{
+									{
+										Type: "Traversal",
+										Children: []TestTreeNode{
+											{
+												Type: "TraverseName",
+												Children: []TestTreeNode{
+													{
+														Type: "identifier",
+														Val:  " foo",
+													},
+												},
+											},
+										},
+									},
+									{
+										Type: "Tokens",
+										Val:  ".*",
+									},
+								},
+							},
+							{
+								Type: "comments",
+							},
+							{
+								Type: "Tokens",
+								Val:  "\n",
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			"a = foo.*.bar\n",
+			TestTreeNode{
+				Type: "Body",
+				Children: []TestTreeNode{
+					{
+						Type: "Attribute",
+						Children: []TestTreeNode{
+							{
+								Type: "comments",
+							},
+							{
+								Type: "identifier",
+								Val:  "a",
+							},
+							{
+								Type: "Tokens",
+								Val:  " =",
+							},
+							{
+								Type: "Expression",
+								Children: []TestTreeNode{
+									{
+										Type: "Traversal",
+										Children: []TestTreeNode{
+											{
+												Type: "TraverseName",
+												Children: []TestTreeNode{
+													{
+														Type: "identifier",
+														Val:  " foo",
+													},
+												},
+											},
+										},
+									},
+									{
+										Type: "Tokens",
+										Val:  ".*.bar",
+									},
+								},
+							},
+							{
+								Type: "comments",
+							},
+							{
+								Type: "Tokens",
+								Val:  "\n",
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			"a = foo[*]\n",
+			TestTreeNode{
+				Type: "Body",
+				Children: []TestTreeNode{
+					{
+						Type: "Attribute",
+						Children: []TestTreeNode{
+							{
+								Type: "comments",
+							},
+							{
+								Type: "identifier",
+								Val:  "a",
+							},
+							{
+								Type: "Tokens",
+								Val:  " =",
+							},
+							{
+								Type: "Expression",
+								Children: []TestTreeNode{
+									{
+										Type: "Traversal",
+										Children: []TestTreeNode{
+											{
+												Type: "TraverseName",
+												Children: []TestTreeNode{
+													{
+														Type: "identifier",
+														Val:  " foo",
+													},
+												},
+											},
+										},
+									},
+									{
+										Type: "Tokens",
+										Val:  "[*]",
+									},
+								},
+							},
+							{
+								Type: "comments",
+							},
+							{
+								Type: "Tokens",
+								Val:  "\n",
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			"a = foo[*].bar\n",
+			TestTreeNode{
+				Type: "Body",
+				Children: []TestTreeNode{
+					{
+						Type: "Attribute",
+						Children: []TestTreeNode{
+							{
+								Type: "comments",
+							},
+							{
+								Type: "identifier",
+								Val:  "a",
+							},
+							{
+								Type: "Tokens",
+								Val:  " =",
+							},
+							{
+								Type: "Expression",
+								Children: []TestTreeNode{
+									{
+										Type: "Traversal",
+										Children: []TestTreeNode{
+											{
+												Type: "TraverseName",
+												Children: []TestTreeNode{
+													{
+														Type: "identifier",
+														Val:  " foo",
+													},
+												},
+											},
+										},
+									},
+									{
+										Type: "Tokens",
+										Val:  "[*].bar",
+									},
+								},
+							},
+							{
+								Type: "comments",
+							},
+							{
+								Type: "Tokens",
+								Val:  "\n",
+							},
+						},
+					},
+				},
+			},
+		},
 		{
 			"a = foo[bar]\n",
 			TestTreeNode{