Fix NodePattern raising errors on some inputs

lib/rubocop/node_pattern.rb

@@ -180,11 +180,16 @@ def compile_seq(tokens, cur_node, seq_head)
         # temp variable as 'cur_node'
         with_temp_node(cur_node) do |init, temp_node|
           terms = compile_seq_terms(tokens, temp_node)
+          terms.unshift(compile_guard_clause(temp_node))
 
-          join_terms(init, terms, ' && ')
+          join_terms(init, terms, " &&\n")
         end
       end
 
+      def compile_guard_clause(cur_node)
+        "#{cur_node}.is_a?(RuboCop::AST::Node)"
+      end
+
       def compile_seq_terms(tokens, cur_node)
         ret, size =
           compile_seq_terms_with_size(tokens, cur_node) do |token, terms, index|
@@ -444,12 +449,6 @@ def emit_trailing_params
         params.empty? ? '' : ",#{params}"
       end
 
-      def emit_guard_clause
-        <<-RUBY
-          return unless node.is_a?(RuboCop::AST::Node)
-        RUBY
-      end
-
       def emit_method_code
         <<-RUBY
           return unless #{@match_code}
@@ -491,7 +490,6 @@ def def_node_matcher(method_name, pattern_str)
         compiler = Compiler.new(pattern_str, 'node')
         src = "def #{method_name}(node = self" \
               "#{compiler.emit_trailing_params});" \
-              "#{compiler.emit_guard_clause}" \
               "#{compiler.emit_method_code};end"
 
         location = caller_locations(1, 1).first
@@ -556,7 +554,7 @@ def initialize(str)
       compiler = Compiler.new(str)
       src = "def match(node0#{compiler.emit_trailing_params});" \
             "#{compiler.emit_method_code}end"
-      instance_eval(src)
+      instance_eval(src, __FILE__, __LINE__ + 1)
     end
   end
 end

spec/rubocop/node_pattern_spec.rb

@@ -160,6 +160,13 @@
 
       it_behaves_like 'matching'
     end
+
+    context 'against a node pattern (bug #5470)' do
+      let(:pattern) { '(:send (:const ...) ...)' }
+      let(:ruby) { 'foo' }
+
+      it_behaves_like 'nonmatching'
+    end
   end
 
   describe 'simple sequence' do
@@ -435,6 +442,20 @@
       it_behaves_like 'single capture'
     end
 
+    context 'in head position in a sequence against nil (bug #5470)' do
+      let(:pattern) { '($_ ...)' }
+      let(:ruby) { '' }
+
+      it_behaves_like 'nonmatching'
+    end
+
+    context 'in head position in a sequence against literal (bug #5470)' do
+      let(:pattern) { '(int ($_ ...))' }
+      let(:ruby) { '42' }
+
+      it_behaves_like 'nonmatching'
+    end
+
     context 'in non-head position in a sequence' do
       let(:pattern) { '(send $_ ...)' }
       let(:ruby) { 'A.method' }