Fix + test for assignment in value but not tail position

Author: c42f

src/linear_ir.jl

@@ -666,7 +666,6 @@ function compile(ctx::LinearIRContext, ex, needs_value, in_tail_pos)
                 if in_tail_pos
                     emit_return(ctx, ex, r)
                 else
-                    @assert false "If this code is reachable, add a test case"
                     r
                 end
             else

test/assignments.jl

@@ -23,6 +23,16 @@ let
 end
 """) == 42
 
+# Assignment in value but not tail position
+@test JuliaLowering.include_string(test_mod, """
+let
+    x = begin
+        y = 42
+    end
+    x
+end
+""") == 42
+
 @test JuliaLowering.include_string(test_mod, """
 let
     x = []

test/assignments_ir.jl

@@ -23,6 +23,21 @@ end
 5   (= slot₃/c %₂)
 6   (return %₂)
 
+########################################
+# Assignment in value but not tail position
+let
+    x = begin
+        y = 42
+    end
+    x
+end
+#---------------------
+1   42
+2   (= slot₂/y %₁)
+3   (= slot₁/x %₁)
+4   slot₁/x
+5   (return %₄)
+
 ########################################
 # short form function def, not chain of assignments
 begin