features: centralize error semantics, remove maxMiscType, etc.

asm/instruction.go

@@ -20,7 +20,7 @@ const InstructionSize = 8
 type RawInstructionOffset uint64
 
 var ErrUnsatisfiedMapReference = errors.New("unsatisfied map reference")
-var ErrUnsatisfiedReference = errors.New("unsatisfied reference")
+var ErrUnsatisfiedProgramReference = errors.New("unsatisfied program reference")
 
 // Bytes returns the offset of an instruction in bytes.
 func (rio RawInstructionOffset) Bytes() uint64 {
@@ -584,7 +584,7 @@ func (insns Instructions) FixupReferences() error {
 			// no fixup needed
 			continue
 		}
-		return fmt.Errorf("%s at insn %d: symbol %q: %w", ins.OpCode, i, ins.Reference, ErrUnsatisfiedReference)
+		return fmt.Errorf("%s at insn %d: symbol %q: %w", ins.OpCode, i, ins.Reference, ErrUnsatisfiedProgramReference)
 	}
 	return nil
 }

linker_test.go

@@ -74,8 +74,8 @@ func TestForwardFunctionDeclaration(t *testing.T) {
 
 		// This program calls an unimplemented forward function declaration.
 		_, err = NewProgram(spec)
-		if !errors.Is(err, asm.ErrUnsatisfiedReference) {
-			t.Fatal("Expected an error wrapping errUnsatisfiedProgram, got:", err)
+		if !errors.Is(err, asm.ErrUnsatisfiedProgramReference) {
+			t.Fatal("Expected an error wrapping ErrUnsatisfiedProgramReference, got:", err)
 		}
 
 		// Append the implementation of fwd().

prog_test.go

@@ -375,7 +375,7 @@ func TestProgramWithUnsatisfiedMap(t *testing.T) {
 
 	_, err = NewProgram(progSpec)
 	if !errors.Is(err, asm.ErrUnsatisfiedMapReference) {
-		t.Fatal("Expected an error wrapping errUnsatisfiedMapReference, got", err)
+		t.Fatal("Expected an error wrapping asm.ErrUnsatisfiedMapReference, got", err)
 	}
 	t.Log(err)
 }