Ensure all case are exhaustive

samples/brainfuck.cr

@@ -45,6 +45,7 @@ class Program
       when '.'; print tape.get.chr
       when '['; pc = @bracket_map[pc] if tape.get == 0
       when ']'; pc = @bracket_map[pc] if tape.get != 0
+      else # skip
       end
       pc += 1
     end

samples/llvm/brainfuck.cr

@@ -145,7 +145,7 @@ class Program
     program = [] of Instruction
     i = from
     while i < to
-      case source[i]
+      case char = source[i]
       when '+'
         program << Increment.new(1)
       when '-'
@@ -167,6 +167,8 @@ class Program
         i = matching_close_index
       when ']'
         abort "Unmatched ']' at position #{i}"
+      else
+        # skip
       end
       i += 1
     end
@@ -181,6 +183,8 @@ class Program
         open_count += 1
       when ']'
         open_count -= 1
+      else
+        # go on
       end
 
       if open_count == 0

samples/mt_gc_test.cr

@@ -195,10 +195,16 @@ def run(threads_num, fibers_num, loops_num, log)
   context.log "Done"
 end
 
+enum Mode
+  Run
+  Ips
+  Measure
+end
+
 threads_num = 4
 fibers_num = 1_000
 loops_num = 20
-mode = :run
+mode : Mode = :run
 
 OptionParser.parse do |parser|
   parser.on("-i", "--ips", "Benchmark with ips") { mode = :ips }
@@ -218,12 +224,12 @@ OptionParser.parse do |parser|
 end
 
 case mode
-when :run
+when .run?
   run(threads_num, fibers_num, loops_num, true)
-when :ips
+when .ips?
   Benchmark.ips do |x|
     x.report("run") { run(threads_num, fibers_num, loops_num, false) }
   end
-when :measure
+when .measure?
   puts Benchmark.measure { run(threads_num, fibers_num, loops_num, false) }
 end

samples/pretty_json.cr

@@ -20,32 +20,34 @@ class PrettyPrinter
 
   def read_any
     case @pull.kind
-    when :null
+    when .null?
       with_color.bold.surround(@output) do
         @pull.read_null.to_json(@output)
       end
-    when :bool
+    when .bool?
       with_color.light_blue.surround(@output) do
         @pull.read_bool.to_json(@output)
       end
-    when :int
+    when .int?
       with_color.red.surround(@output) do
         @pull.read_int.to_json(@output)
       end
-    when :float
+    when .float?
       with_color.red.surround(@output) do
         @pull.read_float.to_json(@output)
       end
-    when :string
+    when .string?
       with_color.yellow.surround(@output) do
         @pull.read_string.to_json(@output)
       end
-    when :begin_array
+    when .begin_array?
       read_array
-    when :begin_object
+    when .begin_object?
       read_object
-    when :EOF
+    when .eof?
       # We are done
+    when .end_array?, .end_object?
+      raise "Bug: shouldn't happen"
     end
   end
 

samples/sdl/fire.cr

@@ -386,6 +386,8 @@ while true
         speed_down[3] = true
       when LibSDL::Key::L
         turn_right[3] = true
+      else
+        # ignore
       end
     when LibSDL::KEYUP
       case event.key.key_sym.sym
@@ -421,7 +423,11 @@ while true
         speed_down[3] = false
       when LibSDL::Key::L
         turn_right[3] = false
+      else
+        # ignore
       end
+    else
+      # ignore
     end
   end
 

samples/sdl/tv.cr

@@ -1,6 +1,17 @@
 require "./sdl/sdl"
 
 class ColorMaker
+  enum State
+    BlueUp
+    BlueDown
+    GreenUp
+    GreenDown
+    RedUp
+    RedDown
+  end
+
+  @state : State
+
   def initialize(@delay : Int32)
     @r = 0
     @g = 255
@@ -19,22 +30,22 @@ class ColorMaker
 
   def next_state
     case @state
-    when :green_up
+    when .green_up?
       @g += 1
       @state = :red_down if @g == 255
-    when :red_down
+    when .red_down?
       @r -= 1
       @state = :blue_up if @r == 0
-    when :blue_up
+    when .blue_up?
       @b += 1
       @state = :green_down if @b == 255
-    when :green_down
+    when .green_down?
       @g -= 1
       @state = :red_up if @g == 0
-    when :red_up
+    when .red_up?
       @r += 1
       @state = :blue_down if @r == 255
-    when :blue_down
+    when .blue_down?
       @b -= 1
       @state = :green_up if @b == 0
     end

spec/compiler/semantic/splat_spec.cr

@@ -539,6 +539,8 @@ describe "Semantic: splat" do
           expect_splat "x", 0, 10, 0
         when 1
           expect_splat "y", 1, 20, 1
+        else
+          fail "shouldn't happen"
         end
         i += 1
       end
@@ -560,6 +562,8 @@ describe "Semantic: splat" do
           expect_splat "a1", 0, 10, 0
         when 1
           expect_splat "a2", 1, 20, 1
+        else
+          fail "shouldn't happen"
         end
         i += 1
       end
@@ -576,6 +580,8 @@ describe "Semantic: splat" do
           expect_splat "a3", 2, 50, 4
         when 3
           expect_splat "a3", 2, 60, 5
+        else
+          fail "shouldn't happen"
         end
         i += 1
       end