Sema: add error for dereferencing comptime value at runtime

src/Sema.zig

@@ -20961,6 +20961,9 @@ fn analyzeLoad(
         }
     }
 
+    const valid_rt = try sema.validateRunTimeType(block, src, elem_ty, false);
+    if (!valid_rt) return sema.failWithNeededComptime(block, src);
+
     try sema.requireRuntimeBlock(block, src);
     return block.addTyOp(.load, elem_ty, ptr);
 }

test/cases/compile_errors/dereference_anyopaque.zig

@@ -0,0 +1,50 @@
+const std = @import("std");
+
+const Error = error{Something};
+
+fn next() Error!void {
+    return;
+}
+
+fn parse(comptime T: type, allocator: std.mem.Allocator) !void {
+    parseFree(T, undefined, allocator);
+    _ = (try next()) != null;
+}
+
+fn parseFree(comptime T: type, value: T, allocator: std.mem.Allocator) void {
+    switch (@typeInfo(T)) {
+        .Struct => |structInfo| {
+            inline for (structInfo.fields) |field| {
+                if (!field.is_comptime)
+                    parseFree(field.field_type, undefined, allocator);
+            }
+        },
+        .Pointer => |ptrInfo| {
+            switch (ptrInfo.size) {
+                .One => {
+                    parseFree(ptrInfo.child, value.*, allocator);
+                },
+                .Slice => {
+                    for (value) |v|
+                        parseFree(ptrInfo.child, v, allocator);
+                },
+                else => unreachable,
+            }
+        },
+        else => unreachable,
+    }
+}
+
+pub export fn entry() void {
+    const allocator = std.testing.allocator_instance.allocator();
+    _ = parse(std.StringArrayHashMap(bool), allocator) catch return;
+}
+
+// error
+// backend=llvm
+//
+// :11:22: error: comparison of 'void' with null
+// :25:51: error: unable to resolve comptime value
+// :25:51: error: unable to resolve comptime value
+// :25:51: error: unable to resolve comptime value
+// :25:51: error: unable to resolve comptime value