diff --git a/doc/langref.html.in b/doc/langref.html.in
index a8673a3d77..92c1aeba8e 100644
--- a/doc/langref.html.in
+++ b/doc/langref.html.in
@@ -5096,7 +5096,7 @@ fn gimmeTheBiggerInteger(a: u64, b: u64) u64 {
       <p>
       For example, if we were to introduce another function to the above snippet:
       </p>
-      {#code_begin|test_err|values of type 'type' must be comptime known#}
+      {#code_begin|test_err|cannot store runtime value in type 'type'#}
 fn max(comptime T: type, a: T, b: T) T {
     return if (a > b) a else b;
 }
diff --git a/src/all_types.hpp b/src/all_types.hpp
index 5b75d9f96a..4be6f57593 100644
--- a/src/all_types.hpp
+++ b/src/all_types.hpp
@@ -335,8 +335,9 @@ struct ConstExprValue {
         RuntimeHintSlice rh_slice;
     } data;
 
-    ConstExprValue(const ConstExprValue &other) = delete; // plz zero initialize with {}
-    ConstExprValue& operator= (const ConstExprValue &other) = delete; // use copy_const_val
+    // uncomment these to find bugs. can't leave them uncommented because of a gcc-9 warning
+    //ConstExprValue(const ConstExprValue &other) = delete; // plz zero initialize with {}
+    //ConstExprValue& operator= (const ConstExprValue &other) = delete; // use copy_const_val
 };
 
 enum ReturnKnowledge {
diff --git a/src/codegen.cpp b/src/codegen.cpp
index 2e430a60e0..0942c671ff 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -691,7 +691,9 @@ static ZigLLVMDIScope *get_di_scope(CodeGen *g, Scope *scope) {
                 is_definition, scope_line, flags, is_optimized, nullptr);
 
             scope->di_scope = ZigLLVMSubprogramToScope(subprogram);
-            ZigLLVMFnSetSubprogram(fn_llvm_value(g, fn_table_entry), subprogram);
+            if (!g->strip_debug_symbols) {
+                ZigLLVMFnSetSubprogram(fn_llvm_value(g, fn_table_entry), subprogram);
+            }
             return scope->di_scope;
         }
         case ScopeIdDecls:
diff --git a/src/ir.cpp b/src/ir.cpp
index 794d41ce22..480493d2ce 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -10726,6 +10726,8 @@ static ZigType *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_node, ZigT
         } else if (prev_inst->value.type->id == ZigTypeIdOptional) {
             return prev_inst->value.type;
         } else {
+            if ((err = type_resolve(ira->codegen, prev_inst->value.type, ResolveStatusSizeKnown)))
+                return ira->codegen->builtin_types.entry_invalid;
             return get_optional_type(ira->codegen, prev_inst->value.type);
         }
     } else {
@@ -21547,7 +21549,7 @@ static IrInstruction *ir_analyze_instruction_from_bytes(IrAnalyze *ira, IrInstru
 
     IrInstruction *result_loc = ir_resolve_result(ira, &instruction->base, instruction->result_loc,
             dest_slice_type, nullptr, true, false);
-    if (type_is_invalid(result_loc->value.type) || instr_is_unreachable(result_loc)) {
+    if (result_loc != nullptr && (type_is_invalid(result_loc->value.type) || instr_is_unreachable(result_loc))) {
         return result_loc;
     }
 
diff --git a/std/event/lock.zig b/std/event/lock.zig
index 6e7a2bbda7..6c2b29b813 100644
--- a/std/event/lock.zig
+++ b/std/event/lock.zig
@@ -123,8 +123,7 @@ pub const Lock = struct {
 };
 
 test "std.event.Lock" {
-    // https://github.com/ziglang/zig/issues/2377
-    //if (true) return error.SkipZigTest;
+    if (builtin.single_threaded) return error.SkipZigTest;
 
     const allocator = std.heap.direct_allocator;